Body mass index and risk of tuberculosis and death

Effectiveness of food supplement on treatment outcomes and quality of life in pulmonary tuberculosis: Phased implementation approach

BACKGROUND

By encouraging treatment adherence and lowering mortality, dietary supplements can serve as adjuvant therapy for the success of medical interventions. We determined the effect of locally accessible food supplements on treatment outcomes, and health-related quality of life in patients with pulmonary tuberculosis initiating anti-tuberculosis treatment (ATT) in Odisha, India.

METHOD

Between September 2017 and December 2018, implementation research in patients with newly diagnosed sputum smear-positive pulmonary tuberculosis initiating ATT in five districts of the tribal belt of Odisha, offered food supplements along with ATT in a phased manner. Clinical symptoms, anthropometry, sputum for M. tuberculosis (M. tb), health-related quality of life and return to normal function were assessed periodically, and favourable treatment outcome (cure or treatment completed) was measured at the end of treatment. The effect of the food supplement on unfavorable outcomes (treatment failure, death, or lost-to-follow-up) was modelled using mixed-effects Poisson regression to determine the risk factors.

RESULTS

Among the 761 participants enrolled, 614 participants received the food supplement and 147 did not receive the food supplement. Among the 614 participants in the supplement group, 537 (87%) had a favorable outcome and among the 147 participants in the no-supplement group, 113 (77%) had a favorable outcome (p = 0.0017). Higher age (>55 years) [aRR = 2.1(95% CI: 1.1-3.8)], male gender [aRR = 1.7(95% CI: 1.2-2.9)], and smear grading ≥2+ [aRR = 1.5 (95% CI: 1.1-2.2)] were associated with unfavorable treatment outcomes. Nutritional status, quality of life and lung health showed significant improvement from baseline in the supplement group.

CONCLUSION

Improvement in the nutritional status of the patient can be considered a predictor of treatment success rates. Early food supplementation has a positive impact on the nutritional status.

Undernutrition as a risk factor for tuberculosis disease

BACKGROUND

Tuberculosis (TB) is a leading cause of mortality due to an infectious disease, with an estimated 1.6 million deaths due to TB in 2022. Approximately 25% of the global population has TB infection, giving rise to 10.6 million episodes of TB disease in 2022. Undernutrition is a key risk factor for TB and was linked to an estimated 2.2 million TB episodes in 2022, as outlined in the World Health Organization (WHO) Global Tuberculosis Report.

OBJECTIVES

To determine the prognostic value of undernutrition in the general population of adults, adolescents, and children for predicting tuberculosis disease over any time period.

SEARCH METHODS

We searched the literature databases MEDLINE (via PubMed) and WHO Global Index Medicus, as well as the WHO International Clinical Trials Registry Platform (ICTRP) on 3 May 2023 (date of last search for all databases). We placed no restrictions on the language of publication.

SELECTION CRITERIA

We included retrospective and prospective cohort studies, irrespective of publication status or language. The target population comprised adults, adolescents, and children from diverse settings, encompassing outpatient and inpatient cohorts, with varying comorbidities and risk of exposure to tuberculosis.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology and the Quality In Prognosis Studies (QUIPS) tool to assess the risk of bias of the studies. Prognostic factors included undernutrition, defined as wasting, stunting, and underweight, with specific measures such as body mass index (BMI) less than two standard deviations below the median for children and adolescents and low BMI scores (< 18.5) for adults and adolescents. Prognostication occurred at enrolment/baseline. The primary outcome was the incidence of TB disease. The secondary outcome was recurrent TB disease. We performed a random-effects meta-analysis for the adjusted hazard ratios (HR), risk ratios (RR), or odds ratios (OR), employing the restricted maximum likelihood estimation. We rated the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 51 cohort studies with over 27 million participants from the six WHO regions. Sixteen large population-based studies were conducted in China, Singapore, South Korea, and the USA, and 25 studies focused on people living with HIV, which were mainly conducted in the African region. Most studies were in adults, four in children, and three in children and adults. Undernutrition as an exposure was usually defined according to standard criteria; however, the diagnosis of TB did not include a confirmatory culture or molecular diagnosis using a WHO-approved rapid diagnostic test in eight studies. The median follow-up time was 3.5 years, and the studies primarily reported an adjusted hazard ratio from a multivariable Cox-proportional hazard model. Hazard ratios (HR) The HR estimates represent the highest certainty of the evidence, explored through sensitivity analyses and excluding studies at high risk of bias. We present 95% confidence intervals (CI) and prediction intervals, which present between-study heterogeneity represented in a measurement of the variability of effect sizes (i.e. the interval within which the effect size of a new study would fall considering the same population of studies included in the meta-analysis). Undernutrition may increase the risk of TB disease (HR 2.23, 95% CI 1.83 to 2.72; prediction interval 0.98 to 5.05; 23 studies; 2,883,266 participants). The certainty of the evidence is low due to a moderate risk of bias across studies and inconsistency. When stratified by follow-up time, the results are more consistent across < 10 years follow-up (HR 2.02, 95% CI 1.74 to 2.34; prediction interval 1.20 to 3.39; 22 studies; 2,869,077 participants). This results in a moderate certainty of evidence due to a moderate risk of bias across studies. However, at 10 or more years of follow-up, we found only one study with a wider CI and higher HR (HR 12.43, 95% CI 5.74 to 26.91; 14,189 participants). The certainty of the evidence is low due to the moderate risk of bias and indirectness. Odds ratio (OR) Undernutrition may increase the odds of TB disease, but the results are uncertain (OR 1.56, 95% CI 1.13 to 2.17; prediction interval 0.61 to 3.99; 8 studies; 173,497 participants). Stratification by follow-up was not possible as all studies had a follow-up of < 10 years. The certainty of the evidence is very low due to the high risk of bias and inconsistency. Contour-enhanced funnel plots were not reported due to the few studies included. Risk ratio (RR) Undernutrition may increase the risk of TB disease (RR 1.95, 95% CI 1.72 to 2.20; prediction interval 1.49 to 2.55; 4 studies; 1,475,867 participants). Stratification by follow-up was not possible as all studies had a follow-up of < 10 years. The certainty of the evidence is low due to the high risk of bias. Contour-enhanced funnel plots were not reported due to the few studies included.

AUTHORS' CONCLUSIONS

Undernutrition probably increases the risk of TB two-fold in the short term (< 10 years) and may also increase the risk in the long term (> 10 years). Policies targeted towards the reduction of the burden of undernutrition are not only needed to alleviate human suffering due to undernutrition and its many adverse consequences, but are also an important part of the critical measures for ending the TB epidemic by 2030. Large population-based cohorts, including those derived from high-quality national registries of exposures (undernutrition) and outcomes (TB disease), are needed to provide high-certainty estimates of this risk across different settings and populations, including low and middle-income countries from different WHO regions. Moreover, studies including children and adolescents and state-of-the-art methods for diagnosing TB would provide more up-to-date information relevant to practice and policy.

FUNDING

World Health Organization (203256442).

REGISTRATION

PROSPERO registration: CRD42023408807 Protocol: https://doi.org/10.1002/14651858.CD015890.

Relationship between metformin use and mortality in tuberculosis patients with diabetes: a nationwide cohort study

BACKGROUND/AIMS

To determine whether metformin, which is considered a host-directed therapy for tuberculosis (TB), is effective in improving the prognosis of patients with TB and diabetes mellitus (DM), who have higher mortality than those without DM.

METHODS

This cohort study included patients who were registered as having TB in the National Tuberculosis Surveillance System. The medical and death records of matched patients were obtained from the National Health Information Database and Statistics Korea, respectively, and data from 2011 to 2017 were collected retrospectively. We classified patients according to metformin use among participants who used diabetes drugs for more than 28 days. The primary outcome was all-cause mortality during TB treatment. Double propensity score adjustment was applied to reduce the effects of confounding and multivariable Cox proportional hazard models were used to estimate adjusted hazard ratio (aHR) with 95% confidence interval (CI).

RESULTS

The all-cause mortality rate during TB treatment was lower (9.5% vs. 12.4%, p < 0.01) in the metformin user group. The hazard of death due to all causes after double propensity score adjustment was also lower in the metformin user group (aHR 0.76, 95% CI 0.67-0.86, p < 0.01). There was no significant difference in mortality between metformin users and non-users for TB-related deaths (p = 0.22); however, there was a significant difference in the non-TB-related deaths (p < 0.01).

CONCLUSION

Metformin use in patients with TB-DM co-prevalence is associated with reduced all-cause mortality, suggesting the potential for metformin adjuvant therapy in these patients.

Models of body weight and fatness regulation

Body weight and fatness appear to be regulated phenomena. Several different theoretical models are available to capture the essence of this idea. These include the set-point, dynamic equilibrium, adiposity force, control theory-settling point, Hall-Guo, operation point and dual intervention point (DIP) models. The set-point model posits a single reference point around which levels of fat are regulated. The dynamic equilibrium model suggests that the apparent regulation of body fat around a reference point is an illusion owing to the necessary impacts of weight change on energy expenditure. Control theory focuses on the importance of feedback gain and suggests set-point and dynamic equilibrium are ends of a continuum of feedback gain. Control theory models have also been called 'settling point' models. The Hall-Guo, operation point and DIP models also bring together the set-point and dynamic equilibrium ideas into a single framework. The DIP proposes a zone of indifference where dynamic equilibrium 'regulation' predominates, bounded by upper and lower intervention points beyond which physiological mechanisms are activated. The drifty gene hypothesis is an idea explaining where this individual variation in the upper intervention point might come from. We conclude that further experiments to test between the models are sorely required. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part II)'.

Healthcare workers' knowledge and practice of the South African national tuberculosis management guidelines

BACKGROUND

Tuberculosis (TB) remains a global public health concern. The 2014 South African (SA) national TB management guidelines were developed to decrease the burden of TB, but implementation remains a challenge.

OBJECTIVES

 To estimate healthcare workers' level of knowledge about the national TB management guidelines and to assess the implementation of these guidelines.

METHODS

A cross-sectional descriptive study was conducted in four randomly selected health facilities in Dr Kenneth Kaunda district, North West Province, SA. We administered a TB knowledge questionnaire and reviewed TB registers and 204 patient files.

RESULTS

 A total of 38 participants completed the TB knowledge questionnaire. The majority were professional nurses (89%). The participants' mean (standard deviation) age was 46 (8) years, and the median (interquartile range) career length was 10 (8 - 17) years. Inadequate knowledge of the national TB management guidelines was revealed in 12 participants (32%). The review of the TB register showed that 163 153 patients were screened for TB. Of these, 9 308 (6%) had presumptive TB, 8 116 (87%) had an Xpert test and 1 292 (16%) had positive Xpert results. Overall, 1 150 (12%) of the patients with presumptive TB were diagnosed with drug-sensitive TB and started treatment based on laboratory results and a clinical diagnosis. Of this sample, 999 patients (87%) were treated successfully. The patient file review showed that a total of 197 patients (97%) received the correct treatment dose according to body weight and treatment phase. Smear microscopy was consistently done throughout the intensive and continuation phases of TB treatment. Body weight was monitored in 199 patients (98%). Contact investigation was conducted for 133 patients (65%), and there was evidence that child contacts aged <5 years were started on isoniazid preventive therapy. Only 110 patients (54%) had documented HIV status. Of these, 66 (60%) were HIV positive, and 39 (59%) of them received antiretroviral therapy. Body mass index was monitored in 55 patients (27%). Eighty (39%) of the patients with TB were women of childbearing potential, and only 8 (10%) of them had their pregnancy test results recorded. Treatment side-effects were reported in 17 patient files (8%); 13 (76%) were managed and 8 (62%) had resolved side-effects.

CONCLUSION

Most participants had adequate knowledge of the national TB management guidelines. A high TB treatment success rate was noted, along with some good practices. The study also highlights several knowledge and practice gaps that can be overcome by measures such as quality audits to improve record keeping. Adequate training of healthcare workers, sustaining and updating knowledge through continuous training, and strengthened supervision mechanisms to ensure compliance with the guidelines are recommended.

Obesity: an evolutionary context

People completely lacking body fat (lipodystrophy/lipoatrophy) and those with severe obesity both show profound metabolic and other health issues. Regulating levels of body fat somewhere between these limits would, therefore, appear to be adaptive. Two different models might be contemplated. More traditional is a set point (SP) where the levels are regulated around a fixed level. Alternatively, dual-intervention point (DIP) is a system that tolerates fairly wide variation but is activated when critically high or low levels are breached. The DIP system seems to fit our experience much better than an SP, and models suggest that it is more likely to have evolved. A DIP system may have evolved because of two contrasting selection pressures. At the lower end, we may have been selected to avoid low levels of fat as a buffer against starvation, to avoid disease-induced anorexia, and to support reproduction. At the upper end, we may have been selected to avoid excess storage because of the elevated risks of predation. This upper limit of control seems to have malfunctioned because some of us deposit large fat stores, with important negative health effects. Why has evolution not protected us against this problem? One possibility is that the protective system slowly fell apart due to random mutations after we dramatically reduced the risk of being predated during our evolutionary history. By chance, it fell apart more in some people than others, and these people are now unable to effectively manage their weight in the face of the modern food glut. To understand the evolutionary context of obesity, it is important to separate the adaptive reason for storing some fat (i.e. the lower intervention point), from the nonadaptive reason for storing lots of fat (a broken upper intervention point). The DIP model has several consequences, showing how we understand the obesity problem and what happens when we attempt to treat it.

Risk factors associated with tuberculosis recurrence in South Korea determined using a nationwide cohort study

Objective

Prevention of tuberculosis (TB) recurrence is an important issue in TB control. South Korea, a country with a high average income, has been challenged with an intermediate burden of TB. We aimed to estimate the TB recurrence rate after successful completion of the first anti-TB chemotherapy, and to identify the risk factors for the TB recurrence by focusing on co-morbidities and behavioral factors.

Methods

This is a population-based cohort study using data from the National Health Insurance (NHI) database between 2002 and 2013. Newly diagnosed TB patients were identified using the classification of disease codes and prescription records. Final analytical subjects included people who successfully completed the first anti-TB chemotherapy. The primary outcome measure was recurrent TB 6-month after the first treatment completion. A set of associated risk factors, including demographic characteristics, co-morbidities, and health behavior factors were analyzed using Cox regression analysis.

Results

Among 5,446 TB patients, 2,226 (40.1%) completed the first anti-TB treatment. During the follow-up period, 150 (6.7%) patients had TB recurrence, and the crude recurrent rate was 22.6 per 1000 person-years. The majority of recurrence cases (89%) occurred within the first 2-year period. The major findings show that participants who are male (adjusted HR (aHR) = 1.81, at a 95% CI, range: 1.11–2.94), older in age (aHR = 1.07, at a 95% CI, range: 1.00–1.14), have a lower income (aHR = 1.96, at a 95% CI, range: 1.10–3.48) and who are underweight (aHR = 1.92, at a 95% CI, range 1.15–3.20) were at higher risks for TB recurrence.

Conclusion

People who have risk factors for recurrent TB need to improve treatment compliance through more effective TB management, and follow-up observation for one or two years after the treatment completion.

Attributable is preventable: Corrected and revised estimates of population attributable fraction of TB related to undernutrition in 30 high TB burden countries

Introduction

The Global TB Report 2020 estimated the population attributable fractions (PAF) for the major risk factors of TB. Undernourishment emerged as the leading risk factor accounting for 19% of the cases. The WHO however used the terms undernourishment and undernutrition interchangeably in its computation of PAF. Undernourishment is an indirect model derived estimate of decreased per capita energy availability, while undernutrition is defined by direct anthropometric measurements of nutritional status. An estimate of PAF for a risk factor should use the prevalence and the risk ratio of the same risk factor, which is not the case with the current methodology.

Methods

We re- estimated the PAF of undernutrition (instead of undernourishment) in 30 high TB burden countries as defined by WHO for the period 2016–2020, using the prevalence of undernutrition (age standardized estimate of BMI < 18.5 kg/m² in adults for both sexes), and the relative risk (RR) of 3.2. Further, we revised PAF estimates of undernutrition with an RR of 4.49 (95% CI: 2.28, 8.86), in light of recent evidence.

Findings

In 30 high TB burden countries, 24.1% (95% CI: 17.6,30.0) of incident TB is attributable to undernutrition. The PAF of undernutrition was highest in Asian countries, unlike the PAF of undernourishment that was highest in Africa. The corrected estimate led up to 65% increase in number of cases attributable to undernutrition in Asian countries. If a revised relative risk was used, 33.0% (95% CI: 10.1, 60.1) of incident TB cases in the selected countries could be attributable to undernutrition. More than one-third to nearly half of incident TB cases in India could be attributable to undernutrition.

Interpretation

Estimation of the PAF of TB related to undernutrition is methodologically valid and operationally relevant, rather than PAF related to undernourishment, and should be used for future Global TB reports by WHO. Addressing undernutrition, the leading driver of TB in high TB burden countries (especially Asia) could enable achievement of END TB milestones of TB incidence for 2025.

Predicting the risk of active pulmonary tuberculosis in people living with HIV: development and validation of a nomogram

BACKGROUND

Diagnosis of pulmonary tuberculosis (PTB) among people living with HIV (PLHIV) was challenging. The study aimed to develop and validated a simple, convenient screening model for prioritizing TB among PLHIV.

METHODS

The study included eligible adult PLHIV participants who attended health care in Yunnan, China, from January 2016 to July 2019. Participants included before June 2018 were in the primary set; others were in the independent validation set. The research applied the least absolute shrinkage and selection operator regression to identify predictors associated with bacteriological confirmed PTB. The TB nomogram was developed by multivariate logistic regression. The C-index, receiver operating characteristic curve (ROC), the Hosmer-Lemeshow goodness of fit test (H-L), and the calibration curves were applied to evaluate and calibrate the nomogram. The developed nomogram was validated in the validation set. The clinical usefulness was assessed by cutoff analysis and decision curve analysis in the primary set.

RESULT

The study enrolled 766 PLHIV, of which 507 were in the primary set and 259 in the validation set, 21.5% and 14.3% individuals were confirmed PTB in two sets, respectively. The final nomogram included 5 predictors: current CD 4 cell count, the number of WHO screen tool, previous TB history, pulmonary cavity, and smoking status (p < 0.05). The C-statistic was 0.72 (95% CI 0.66-0.77) in primary set and 0.68 (95% CI 0.58-0.75) in validation set, ROC performed better than other models. The nomogram calibration was good (H-L χ² = 8.14, p = 0.15). The area under the decision curve (0.025) outperformed the existing models. The optimal cutoff for screening TB among PLHIV was the score of 100 (sensitivity = 0.93, specificity = 0.35).

CONCLUSION

The study developed and validated a discriminative TB nomogram among PLHIV in the moderate prevalence of TB and HIV. The easy-to-use and straightforward nomogram would be beneficial for clinical practice and rapid risk screening in resource-limited settings.

Incidence and factors associated with active tuberculosis among people living with HIV after long-term antiretroviral therapy in Thailand: a competing risk model

BACKGROUND

Antiretroviral therapy (ART) is known to reduce tuberculosis (TB) incidence among people living with HIV (PLWH). However, studies describing the impact of long-term ART and CD4 count recovery on TB incidence remain scarce due to limited follow up in previous studies. We evaluated TB incidence in a long-term cohort of PLWH on ART in Thailand.

METHODS

We conducted an analysis of PLWH aged ≥ 18 years who started ART between 1996 and December 2020. Participants were followed up every 6 months for routine HIV care. TB risk factors, body mass index (BMI), physical examination and full differential blood counts were evaluated at each clinic visit, and CD4 cell counts and HIV RNA every 12 months. Participants diagnosed with TB > 3 months after starting ART were classified as incident cases. Time to event models with death as a competing risk, were used to derive the TB cumulative incidence function (CIF) after ART initiation, and assess time-updated factors associated with incident TB using a six month lag.

RESULTS

A total of 2,636 PLWH contributing 24,229 person years (PY) of follow-up on ART were analysed. Median age was 32.0 (IQR 27.4-37.6) years; 67.5% were male. Median CD4 cell count at ART initiation was 264 (IQR 167-379) cells/mm³ and median follow-up duration was 7.6 (IQR 1.9-15.7) years. During follow-up, 113 PLWH developed TB. The probability of incident TB was 0.7%, 1.7%, 3.3% and 4.3%, at 1, 2, 5 and 7 years after ART initiation, respectively. TB CIF was highest among participants with CD4 < 50 cells/mm³. The overall crude incidence of TB was 4.66 (95% CI 3.87-5.60) per 1000 PY. Low CD4 count, BMI < 18 kg/m², and substance use in the previous six months were significantly associated with incident TB. Incidence declined with time on suppressive ART, but remained higher than the Thai general population 7 years after ART initiation (2.2 vs 1.5/1000 PY, respectively).

CONCLUSION

Despite a marked reduction in TB incidence following ART, ongoing TB risk remains high among PLWH, despite long-term suppressive ART. Those with low CD4 cell counts, who are underweight, or currently having substance abuse should be carefully monitored.

Tuberculosis screening among ambulatory people living with HIV: a systematic review and individual participant data meta-analysis

BACKGROUND

The WHO-recommended tuberculosis screening and diagnostic algorithm in ambulatory people living with HIV is a four-symptom screen (known as the WHO-recommended four symptom screen [W4SS]) followed by a WHO-recommended molecular rapid diagnostic test (eg Xpert MTB/RIF [hereafter referred to as Xpert]) if W4SS is positive. To inform updated WHO guidelines, we aimed to assess the diagnostic accuracy of alternative screening tests and strategies for tuberculosis in this population.

METHODS

In this systematic review and individual participant data meta-analysis, we updated a search of PubMed (MEDLINE), Embase, the Cochrane Library, and conference abstracts for publications from Jan 1, 2011, to March 12, 2018, done in a previous systematic review to include the period up to Aug 2, 2019. We screened the reference lists of identified pieces and contacted experts in the field. We included prospective cross-sectional, observational studies and randomised trials among adult and adolescent (age ≥10 years) ambulatory people living with HIV, irrespective of signs and symptoms of tuberculosis. We extracted study-level data using a standardised data extraction form, and we requested individual participant data from study authors. We aimed to compare the W4SS with alternative screening tests and strategies and the WHO-recommended algorithm (ie, W4SS followed by Xpert) with Xpert for all in terms of diagnostic accuracy (sensitivity and specificity), overall and in key subgroups (eg, by antiretroviral therapy [ART] status). The reference standard was culture. This study is registered with PROSPERO, CRD42020155895.

FINDINGS

We identified 25 studies, and obtained data from 22 studies (including 15 666 participants; 4347 [27·7%] of 15 663 participants with data were on ART). W4SS sensitivity was 82% (95% CI 72-89) and specificity was 42% (29-57). C-reactive protein (≥10 mg/L) had similar sensitivity to (77% [61-88]), but higher specificity (74% [61-83]; n=3571) than, W4SS. Cough (lasting ≥2 weeks), haemoglobin (<10 g/dL), body-mass index (<18·5 kg/m2), and lymphadenopathy had high specificities (80-90%) but low sensitivities (29-43%). The WHO-recommended algorithm had a sensitivity of 58% (50-66) and a specificity of 99% (98-100); Xpert for all had a sensitivity of 68% (57-76) and a specificity of 99% (98-99). In the one study that assessed both, the sensitivity of sputum Xpert Ultra was higher than sputum Xpert (73% [62-81] vs 57% [47-67]) and specificities were similar (98% [96-98] vs 99% [98-100]). Among outpatients on ART (4309 [99·1%] of 4347 people on ART), W4SS sensitivity was 53% (35-71) and specificity was 71% (51-85). In this population, a parallel strategy (two tests done at the same time) of W4SS with any chest x-ray abnormality had higher sensitivity (89% [70-97]) and lower specificity (33% [17-54]; n=2670) than W4SS alone; at a tuberculosis prevalence of 5%, this strategy would require 379 more rapid diagnostic tests per 1000 people living with HIV than W4SS but detect 18 more tuberculosis cases. Among outpatients not on ART (11 160 [71·8%] of 15 541 outpatients), W4SS sensitivity was 85% (76-91) and specificity was 37% (25-51). C-reactive protein (≥10 mg/L) alone had a similar sensitivity to (83% [79-86]), but higher specificity (67% [60-73]; n=3187) than, W4SS and a sequential strategy (both test positive) of W4SS then C-reactive protein (≥5 mg/L) had a similar sensitivity to (84% [75-90]), but higher specificity than (64% [57-71]; n=3187), W4SS alone; at 10% tuberculosis prevalence, these strategies would require 272 and 244 fewer rapid diagnostic tests per 1000 people living with HIV than W4SS but miss two and one more tuberculosis cases, respectively.

INTERPRETATION

C-reactive protein reduces the need for further rapid diagnostic tests without compromising sensitivity and has been included in the updated WHO tuberculosis screening guidelines. However, C-reactive protein data were scarce for outpatients on ART, necessitating future research regarding the utility of C-reactive protein in this group. Chest x-ray can be useful in outpatients on ART when combined with W4SS. The WHO-recommended algorithm has suboptimal sensitivity; Xpert for all offers slight sensitivity gains and would have major resource implications.

FUNDING

World Health Organization.

Clinical Features, Diagnostic Test Performance, and Prognosis in Different Subtypes of Chronic Pulmonary Aspergillosis

Objective

The aim of this study was to describe clinical features in different subtypes of chronic pulmonary aspergillosis (CPA)-simple aspergilloma (SA), chronic cavitary pulmonary aspergillosis (CCPA), chronic fibrosing pulmonary aspergillosis (CFPA), aspergillus nodule (AN), and subacute invasive aspergillosis (SAIA), respectively, and identify long-term prognosis of CPA.

Methods

We reviewed patients diagnosed with different subtypes of CPA from 2002 to 2020 at Nanjing Jinling Hospital, China. We analyzed the clinical and survival information of five different subgroups. A Cox regression model was used to explore proper antifungal duration and long-term survival factors of CCPA and SAIA.

Results

A total of 147 patients with CPA were included, consisting of 11 SA, 48 CCPA, 5 CFPA, 12 AN, and 71 SAIA. The most common underlying pulmonary disease was pulmonary tuberculosis (n = 49, 33%), followed by bronchiectasis (n = 46, 31.3%) and chronic obstructive pulmonary disease (COPD) or emphysema (n = 45, 30.6%), while in SAIA and CFPA groups, the most common was COPD or emphysema (45.1 and 100%). Cough (85%), expectoration (70.7%), hemoptysis (54.4%), and fever (29.9%) were common symptoms, especially in CCPA, CFPA, and SAIA groups. The common imaging manifestations included cavitation (n = 94, 63.9%), fungal ball (n = 54, 36.7%), pleural thickening (n = 47, 32.0%), and bronchiectasis (n = 46, 31.3%). SAIA and CFPA groups had a lower value of hemoglobin (HB) and serum albumin (ALB) with higher C-reactive protein and erythrocyte sedimentation rate. The positive rate of sputum culture, serum galactomannan (GM), and bronchoalveolar lavage fluid GM was 32.7% (36/110), 18.4% (18/98), and 48.7% (19/39), respectively. There were 64.6% (31/48) patients with CCPA and 25.4% (18/71) patients with SAIA who received surgery and the 5-year cumulative survival rate was 92.1 and 66.6%, respectively. SAIA, old age, male, low body mass index (BMI), COPD or emphysema, multiple distribution, low serum ALB, and positive sputum culture were adverse prognosis factors for SAIA and CCPA group, and BMI ≤ 20.0 kg/m² was independently associated with increased mortality (hazard ratio (HR) 5.311, 95% CI 1.405–20.068, p = 0.014). Multivariable Cox regression indicated that surgery (HR 0.093, 95% CI 0.011–0.814, p = 0.032) and antifungal duration >6 months (HR 0.204, 95% CI 0.060–0.696 p = 0.011) were related to improved survival.

Conclusion

The clinical features and laboratory test performance are different among SA, CCPA, CFPA, AN, and SAIA. Low BMI was an independent risk factor for survival. Selective surgery and antifungal duration over 6 months were associated with improved survival.

Synergy between low BMI and hyperglycemia at baseline increases tuberculosis incidence among people living with HIV

OBJECTIVES

Low BMI and hyperglycemia are each important risk factors for tuberculosis (TB). However, the contribution of synergy between low BMI and hyperglycemia to risk of TB among people living with HIV (PWH) is unexplored. We compared TB incidence among PWH with different exposure profiles to low BMI (BMI < 18.5 kg/m2) and hyperglycemia (random blood glucose ≥140 mg/dl).

DESIGN AND METHODS

We conducted a cohort study using data of PWH (≥15 years) who enrolled in Myanmar's Integrated HIV Care Program between 2011 and 2017. We used their follow-up data until 2018 to determine TB incidence.

RESULTS

Among 20 865 PWH included in this study, 7610 (36%) had low BMI only, 1324 (6%) had hyperglycemia only, and 465 (2%) patients had concurrent low BMI and hyperglycemia (joint exposure) at baseline. During a median follow-up of 2.2 years (interquartile range: 0.5, 4.2), 3628 (17%) developed TB [6.7, 95% confidence interval (CI): 6.5,7.0 cases per 100 person-years (PY)]. TB incidence among PWH with joint exposure was 21.0 (95% CI: 18.0, 24.7), with low BMI only was 10.9 (95% CI: 10.4, 11.4), with hyperglycemia only was 5.2 (95% CI: 4.4, 6.3) and with no exposure was 4.6 (95% CI: 4.4, 4.9) cases per 100 PY. The attributable proportion of incident TB due to synergy between low BMI and hyperglycemia was 0.23 (95% CI: 0.06, 0.36).

CONCLUSION

Synergy between low BMI and hyperglycemia was associated with increased excess TB incidence in PWH. TB preventive treatment, nutritional support, and hyperglycemia management should be evaluated as interventions to reduce TB risk in PWH with joint exposure.

Systemic DPP4/CD26 is associated with natural HIV-1 control: Implications for COVID-19 susceptibility

The current intersection of the COVID-19 and HIV-1 pandemics, has raised concerns about the risk for poor COVID-19 outcomes particularly in regions like sub-Saharan Africa, disproportionally affected by HIV. DPP4/CD26 has been suggested to be a potential therapeutic target and a biomarker for risk in COVID-19 patients with high risk co-morbidities. We therefore evaluated soluble DPP4 (sDPP4) levels and activity in plasma of 131 HIV-infected and 20 HIV-uninfected South African individuals. Flow cytometry was performed to compare cell surface expression of DPP4/CD26 and activation markers on peripheral blood mononuclear cells of extreme clinical phenotypes. Progressors had lower specific DPP4 activity and lower frequency of CD3⁺ T-cells expressing CD26 than HIV-1 controllers, but more activated CD3⁺CD26⁺ T-cells. The frequency of CD26-expressing T-cells negatively correlated with HLA-DR⁺ and CD38⁺ T-cells. Divergent DPP4/CD26 expression between HIV-1 controllers and progressors may have implications for risk and treatment of COVID-19 in people living with HIV.

A nutritional profile of patients with tuberculosis at Standerton Tuberculosis Specialised Hospital, Mpumalanga, South Africa

Background

Tuberculosis (TB) is strongly influenced by nutritional status, with nutrition interventions being likely to have an impact on the prevalence of disease, response to drugs and quality of life.

Aim

The aim of this research study was to determine the nutritional profile of patients with TB and TB and human immunodeficiency virus (HIV) co-infection.

Setting

The study was conducted at Standerton TB Specialised Hospital, Mpumalanga.

Methods

A cross-sectional study was undertaken. A structured interview was conducted by the researcher with each patient. The Malnutrition Universal Screening Tool (MUST) was used to determine the risk of malnutrition. Weight, height, mid-upper arm circumference (MUAC) and triceps skinfold were measured using standard techniques. Biochemical parameters that were part of the routine hospital procedure were noted.

Results

More than two-thirds of the participants (68%) were found to be HIV positive. Food-related side effects included loss of appetite (59%) and dry mouth (48%). According to the MUST, 70% had a high risk of malnutrition. The median body mass index (BMI) was in the underweight category at 18.3 kg/m². About half of the participants had low MUAC measurements (51%) and triceps skinfold measurements below the 15th percentile (49.9%), indicating malnutrition. Most participants had low albumin and haemoglobin levels (79% and 92%, respectively).

Conclusions

Patients with both TB and TB and HIV co-infection had a compromised nutritional status and an increased risk for developing malnutrition. Interventions aimed at addressing malnutrition could make a meaningful contribution to improving the quality of life in these patients.

Contribution

This research provides evidence on the nutritional profile of patients with tuberculosis at Standerton TB Specialised Hospital, it gives opportunity to extend this research project to confirm these findings in other TB burdened areas.

Impact of Isoniazid Preventive Therapy on Tuberculosis incidence among people living with HIV: A secondary data analysis using Inverse Probability Weighting of individuals attending HIV care and treatment clinics in Tanzania

BACKGROUND

Information on how well Isoniazid Preventive Therapy (IPT) works on reducing TB incidence among people living with HIV (PLHIV) in routine settings using robust statistical methods to establish causality in observational studies is scarce.

OBJECTIVES

To evaluate the effectiveness of IPT in routine clinical settings by comparing TB incidence between IPT and non-IPT groups.

METHODS

We used data from PLHIV enrolled in 315 HIV care and treatment clinic from January 2012 to December 2016. We used Inverse Probability of Treatment Weighting to adjust for the probability of receiving IPT; balancing the baseline covariates between IPT and non-IPT groups. The effectiveness of IPT on TB incidence was estimated using Cox regression using the weighted sample.

RESULTS

Of 171,743 PLHIV enrolled in the clinics over the five years, 10,326 (6.01%) were excluded leaving 161,417 available for the analysis. Of the 24,800 who received IPT, 1.00% developed TB disease whereas of the 136,617 who never received IPT 6,085 (4.98%) developed TB disease. In 278,545.90 person-years of follow up, a total 7,052 new TB cases were diagnosed. Using the weighted sample, the overall TB incidence was 11.57 (95% CI: 11.09-12.07) per 1,000 person-years. The TB incidence among PLHIV who received IPT was 10.49 (95% CI: 9.11-12.15) per 1,000 person-years and 12.00 (95% CI: 11.69-12.33) per 1,000 person-years in those who never received IPT. After adjusting for other covariates there was 52% lower risk of developing TB disease among those who received IPT compared to those who never received IPT: aHR = 0.48 (95% CI: 0.40-0.58, P<0.001).

CONCLUSION

IPT reduced TB incidence by 52% in PLHIV attending routine CTC in Tanzania. IPTW adjusted the groups for imbalances in the covariates associated with receiving IPT to achieve comparable groups of IPT and non-IPT. This study has added evidence on the effectiveness of IPT in routine clinical settings and on the use of IPTW to determine impact of interventions in observational studies.

Higher Serum Cholesterol Levels Are Associated With Reduced Systemic Inflammation and Mortality During Tuberculosis Treatment Independent of Body Mass Index

Background: Lipids play a central role in the pathogenesis of tuberculosis (TB). The effect of serum lipid levels on TB treatment (ATT) outcomes and their association with serum inflammatory markers have not yet been characterized. Methods: Our retrospective cohort study on drug-susceptible TB patients, at the National Taiwan University Hospital, assessed the association of baseline serum lipid levels such as low-density lipoprotein (LDL), high-density lipoprotein (HDL), total cholesterol (TC) and triglycerides (TG) with all-cause and infection-related mortality during first 9 months of ATT and baseline inflammatory markers namely C-reactive protein (CRP), total leukocyte count (WBC), and neutrophil-lymphocyte ratio (NL ratio). Results: Among 514 patients, 129 (26.6%) died due to any-cause and 72 (14.0%) died of infection. Multivariable Cox-regression showed a lower adjusted hazard ratio (aHR) of all-cause mortality in the 3rd tertiles of HDL (aHR 0.17, 95% CI 0.07-0.44) and TC (aHR 0.30, 95% CI 0.14-0.65), and lower infection-related mortality in the 3rd tertile of HDL (aHR 0.30, 95% CI 0.14-0.65) and TC (aHR 0.30, 95% CI 0.14-0.65) compared to the 1st tertile. The 3rd tertiles of LDL and TG showed no association in multivariable analysis. Similarly, 3rd tertiles of HDL and TC had lower levels of baseline inflammatory markers such as CRP, WBC, and NL ratio using linear regression analysis. Body mass index (BMI) did not show evidence of confounding or effect modification. Conclusions: Higher baseline serum cholesterol levels were associated with lower hazards of all-cause and infection-related mortality and lower levels of inflammatory markers in TB patients. BMI did not modify or confound this association.

Malnutrition prevalence and associated biochemical factors among drug-resistance tuberculosis (DR-TB) patients at key treatment sites in Conakry City, Republic of Guinea

Introduction

drug-resistant tuberculosis is a major global health problem and a threat to health security given the increase in the number of cases and the challenges associated with care. Besides, the relationship between poor nutritional status and tuberculosis is clearly established. For relevant and evidence-based public health decision-making regarding the management of malnutrition in patients with drug-resistant tuberculosis in the initial phase, it is essential to estimate the prevalence of malnutrition and understand the risk factors associated with it.

Methods

we performed a retrospective cohort study in drug-resistant tuberculosis patients aged 18 years and older, among which the nutritional status was assessed through BMI. All predictors were included in a prediction model using the multivariate logistic model according to the lowest Akaike criterion. Discrimination and model calibration was evaluated using receiver performance analysis, and the Hosmer and Lemeshow test.

Results

this study revealed a prevalence of malnutrition of 64.7% in drug-resistant tuberculosis patients in our 218-patient series. The factors associated with malnutrition were: unsuccessful treatment, the active presence of mycobacterium tuberculosis, increased bacteriological conversion time, increased serum creatinine, increased transaminase SGPT of the liver, and anaemia. Some of the factors not associated with malnutrition included the history of anti-tuberculosis treatment, vomiting, hepatic SGPT, initial AFB count, smear and culture conversion time, depression, and chest X-ray.

Conclusion

malnutrition remains a concern among drug-resistant tuberculosis patients in Guinea as it affects more than half of them with a negative impact on the outcome of treatment. Implementing specific interventions for these high-risk patients, including nutritional supplementation, psychosocial support, and treatment for tuberculosis, can improve management for better treatment outcomes.

Association of rs12722 COL5A1 with pulmonary tuberculosis: a preliminary case-control study in a Kazakhstani population

Lung cavitation is the classic hallmark of TB, which facilitates the disease development and transmission. It involves the degradation of lung parenchyma which is mainly made up of collagen fibers by metalloproteinases (MMPs) produced by activated monocyte-derived cells, neutrophils and stromal cells. The following population-based preliminary case-control study of adults with TB (50) and controls (112) without TB was used to investigate possible association between rs1800012 in COL1A1, rs12722 in COL5A1 genes and pulmonary TB in Kazakhstan. We examined 162 samples (50 cases and 112 controls) to study the associations between TB disease status and demographic variables along with single nucleotide polymorphisms related to COLA1 and COL5A1. The unadjusted χ2 and multivariable logistic regression was performed to find out relationships between SNP and other predictors. Preliminary findings suggest that there is a statistically significant association of age (AOR = 0.97, 95% CI:0.94-0.99, p value = 0.049), social status (AOR = 2.41, 95% CI:1.16-5.02, p value = 0.018), HIV status (AOR = 7.12, 95% CI:1.90-26.7, p value = 0.004) and heterozygous rs12722 SNP (AOR = 2.47, 95% CI:1.17-5.19, p value = 0.018) polymorphism of COL5A1 gene with TB susceptibility. The association of collagen genes with TB pathogenesis indicates that anti TB programs can include development of new drug regimens that include MMP inhibitors which has been found to be helpful in collagen remodeling and repair. Therapeutic targeting of MMPs will prevent extracellular matrix and collagen degradation and granuloma maturation.

Effects of undernutrition on mortality and morbidity among adults living with HIV in sub-Saharan Africa: a systematic review and meta-analysis

Background

Undernutrition is one of the most common problems among people living with HIV, contributing to premature death and the development of comorbidities within this population. In Sub-Saharan Africa (SSA), the impacts of these often inter-related conditions appear in a series of fragmented and inconclusive studies. Thus, this review examines the pooled effects of undernutrition on mortality and morbidities among adults living with HIV in SSA.

Methods

A systematic literature search was conducted from PubMed, EMBASE, CINAHL, and Scopus databases. All observational studies reporting the effects of undernutrition on mortality and morbidity among adults living with HIV in SSA were included. Heterogeneity between the included studies was assessed using the Cochrane Q-test and I² statistics. Publication bias was assessed using Egger’s and Begg’s tests at a 5% significance level. Finally, a random-effects meta-analysis model was employed to estimate the overall adjusted hazard ratio.

Results

Of 4309 identified studies, 53 articles met the inclusion criteria and were included in this review. Of these, 40 studies were available for the meta-analysis. A meta-analysis of 23 cohort studies indicated that undernutrition significantly (AHR: 2.1, 95% CI: 1.8, 2.4) increased the risk of mortality among adults living with HIV, while severely undernourished adults living with HIV were at higher risk of death (AHR: 2.3, 95% CI: 1.9, 2.8) as compared to mildly undernourished adults living with HIV. Furthermore, the pooled estimates of ten cohort studies revealed that undernutrition significantly increased the risk of developing tuberculosis (AHR: 2.1, 95% CI: 1.6, 2.7) among adults living with HIV.

Conclusion

This review found that undernutrition has significant effects on mortality and morbidity among adults living with HIV. As the degree of undernutrition became more severe, mortality rate also increased. Therefore, findings from this review may be used to update the nutritional guidelines used for the management of PLHIV by different stakeholders, especially in limited-resource settings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-020-05706-z.

Less liver fibrosis marker increment in overweight chronic hepatitis B patients observed by age-adjusted Fibrosis-4 Index

Background and aims

Chronic hepatitis B patients in Taiwan with no or limited liver injury are not reimbursed for antiviral treatment by the Taiwan National Health Insurance (NHI). Innovative fibrosis marker, age-adjusted Fibrosis-4 Index (FIB4-AA), was implemented to evaluate the tendency of liver fibrosis in these patients.

Methods

The FIB-4 indices of 256 antiviral treatment-naïve chronic hepatitis B patients at Kaohsiung Medical University Hospital from 2003 to 2019 were reviewed. The difference in initial FIB-4 and last FIB4-AA was treated as a categorical variable, representing the tendency of liver fibrosis in each individual aside from ageing. Logistic regression was implemented to evaluate the three parameters most dependent on increment of FIB4-AA: e seroconversion, body mass index (BMI) and initial FIB-4 index.

Results

The yearly FIB-4 growth rate of an individual without chronic hepatitis was lower than that of the study group (0.0237 vs 0.0273 for males, 0.02 vs 0.0288 for females). Patients undergoing or completing e seroconversion were less prone to increment of FIB4-AA (p=0.036, OR 0.524). Logistic regression revealed that BMI ≥25 kg/m² significantly less increment of FIB4-AA (p=0.001, OR 0.383, 95% CI 0.212 to 0.690), while patients with initial FIB-4 <1.29 were prone to increasing liver FIB4-AA (p=0.000, OR 3.687, 95% CI 1.999 to 6.797).

Conclusion

Chronic hepatitis B patients not meeting the reimbursement criteria of the Taiwan NHI are prone to increment of liver fibrosis marker. Overweight is associated with less increment of fibrosis marker, while initial FIB-4 <1.29 is associated with increasing fibrosis marker.

Gender difference in mortality among pulmonary tuberculosis HIV co-infected adults aged 15-49 years in Kenya

Setting

Kenya, 2012–2015

Objective

To explore whether there is a gender difference in all-cause mortality among smear positive pulmonary tuberculosis (PTB)/ HIV co-infected patients treated for tuberculosis (TB) between 2012 and 2015 in Kenya.

Design

Retrospective cohort of 9,026 smear-positive patients aged 15–49 years. All-cause mortality during TB treatment was the outcome of interest. Time to start of antiretroviral therapy (ART) initiation was considered as a proxy for CD4 cell count. Those who took long to start of ART were assumed to have high CD4 cell count.

Results

Of the 9,026 observations analysed, 4,567(51%) and 4,459(49%) were women and men, respectively. Overall, out of the 9,026 patients, 8,154 (90%) had their treatment outcome as cured, the mean age in years (SD) was 33.3(7.5) and the mean body mass index (SD) was 18.2(3.4). Men were older (30% men’ vs 17% women in those ≥40 years, p = <0.001) and had a lower BMI <18.5 (55.3% men vs 50.6% women, p = <0.001). Men tested later for HIV: 29% (1,317/4,567) of women HIV tested more than 3 months prior to TB treatment, as compared to 20% (912/4,459) men (p<0.001). Mortality was higher in men 11% (471/4,459) compared to women 9% (401/4,567, p = 0.004). There was a 17% reduction in the risk of death among women (adjusted HR 0.83; 95% CI 0.72–0.96; p = 0.013). Survival varied by age-groups, with women having significantly better survival than men, in the age-groups 40 years and over (log-rank p = 0.006).

Conclusion

Women with sputum positive PTB/HIV co-infection have a significantly lower risk of all-cause mortality during TB treatment compared to men. Men were older, had lower BMI and tested later for HIV than women.

Evaluation of underweight status may improve identification of the highest-risk patients during outpatient evaluation for pulmonary tuberculosis

BACKGROUND

When evaluating symptomatic patients for tuberculosis (TB) without access to same-day diagnostic test results, clinicians often make empiric decisions about starting treatment. The number of TB symptoms and/or underweight status could help identify patients at highest risk for a positive result. We sought to evaluate the usefulness of BMI assessment and a count of characteristic TB symptoms for identifying patients at highest risk for TB.

METHODS

We enrolled adult patients receiving pulmonary TB diagnoses and a representative sample with negative TB evaluations at four outpatient health facilities in Kampala, Uganda. We asked patients about symptoms of chronic cough, night sweats, chest pain, fever, hemoptysis, or weight loss; measured height and weight; and collected sputum for mycobacterial culture. We evaluated the diagnostic accuracy (for culture-positive TB) of two simple scoring systems: (a) number of TB symptoms, and (b) number of TB symptoms plus one or more additional points for underweight status (body mass index [BMI] ≤ 18.5 kg/m2).

RESULTS

We included 121 patients with culture-positive TB and 370 patients with negative culture results (44 of whom had been recommended for TB treatment by evaluating clinicians). Of the six symptoms assessed, the median number of symptoms that patients reported was two (interquartile range [IQR]: 1, 3). The median BMI was 20.9 kg/m2 (IQR: 18.6, 24.0), and 118 (24%) patients were underweight. Counting the number of symptoms provided an area under the Receiver Operating Characteristic curve (c-statistic) of 0.77 (95% confidence interval, CI: 0.72, 0.81) for identifying culture-positive TB; adding two points for underweight status increased the c-statistic to 0.81 (95%CI: 0.76, 0.85). A cutoff of ≥3 symptoms had sensitivity and specificity of 65% and 74%, whereas a score of ≥4 on the combined score (≥2 symptoms if underweight, ≥4 symptoms if not underweight) gave higher sensitivity and specificity of 69% and 81% respectively. A sensitivity analysis defining TB by Xpert MTB/RIF status produced similar results.

CONCLUSION

A count of patients' TB symptoms may be useful in clinical decision-making about TB diagnosis. Consideration of underweight status adds additional diagnostic value.

Increased Prevalence of Liver Fibrosis and HIV Viremia among Patients with HIV, HBV, and Tuberculosis in Botswana

People with concomitant human immunodeficiency virus (HIV) and tuberculosis (TB) have an increased risk of hepatotoxic reactions due to antiretroviral therapy (ART) and anti-TB therapy (ATT). Concomitant hepatitis B virus (HBV) in these patients may lead to poorer health outcomes. To assess liver enzyme levels and immune response in adults with HIV, HBV, and TB, data from 300 antiretroviral-naïve people living with HIV (PLWHIV) were analyzed. The prevalence of HIV/HBV (cHIV/HBV) and HIV/TB (cHIV/TB) was 28% (95% CI: 23.0–33.4) and 10% (95% CI: 6.8–14.0), respectively. HIV/HBV/TB (cHIV/HBV/TB) prevalence was 5.3% (95% CI: 3.1–8.5). There was a statistically significant difference between the groups of participants in HIV viral load (p = 0.004), hemoglobin levels (p = 0.025), and body mass index (p = 0.011). A larger proportion of cHIV/HBV/TB participants (37.5%) had an aspartate aminotransferase to platelet ratio index (APRI) score ≥0.5 (p = 0.013), a lower cutoff for significant liver fibrosis. Immunological non-responders (CD4+ T-cell count <20% gain and HIV viral load <400 copies/mL at 6 months) were observed in all groups except those with cHIV/TB. Our findings support the need to screen for infections that could cause excessive liver damage prior to ATT or ART initiation, such as HBV.

Systematic analysis for the relationship between obesity and tuberculosis

OBJECTIVES

Underweight or low body mass index (BMI) is an established risk factor for active tuberculosis. Recent evidence, however, suggests that overweight is associated with lower incidence of tuberculosis. The objective of this systematic review and meta-analysis is to understand the relationship between obesity and tuberculosis and document the extent of association between the two conditions over the range of BMI from underweight to obesity.

METHODS

A comprehensive literature search was conducted to identify studies reporting prevalence of the different BMIs in patients with tuberculosis and controls. Thirty studies of adult humans reporting the incidence of tuberculosis at different weight categories were selected for inclusion for meta-analysis in the present study.

RESULTS

In tuberculosis, the prevalence of underweight was 3-fold higher than that in controls (P = 0.001) whereas the proportion of overweight and obesity was 2-fold lower (P = 0.001). One unit increase in BMI was associated with 2% reduction in tuberculosis incidence (P < 0.001). Adjusted odds ratio of tuberculosis was 4.96 (95% confidence interval: 4.87-5.05) in underweight and 0.26 in obesity.

CONCLUSION

This study further establishes low body weight as a risk factor for tuberculosis whilst overweight and obesity are associated with lower disease risk. Body weight can be considered as a prognostic indictor in the clinical course of tuberculosis.

Prevalence of and risk factors associated with latent tuberculosis infection in a Latin American region

Tuberculosis (TB) represents a health problem in Colombia, and its control is focused on the search for contacts and treatment of TB cases underscoring the role of latent tuberculosis infection (LTBI) as a reservoir of Mycobacterium tuberculosis. The burden of LTBI in Colombia is unknown. We aimed to estimate the prevalence of LTBI and identify the associated risk factors. In this cross-sectional study, we recruited participants from four health care centers in Cali, Colombia. The participants were eligible if they were aged between 14 and 70 years, and all participants answered a survey evaluating their medical history and sociodemographic and lifestyle factors. LTBI status was based on tuberculin skin test (TST) positivity using two thresholds: ≥10 mm (TST-10) and ≥15 mm (TST-15). The magnitude of the associations between independent factors and dependent outcomes (LTBI status and TST induration) were evaluated by logistic regression and generalized linear models, respectively. A total of 589 individuals were included with TST positivity rates of 25.3% (TST-10) and 13.2% (TST-15). Logistic regression showed that being between age 40 and 69 years (OR = 7.28, 95% CI [1.62–32.7]), being male (OR = 1.71, 95% CI [1.04–2.84]), being employed (OR = 1.56, 95% CI [1.02–2.38]), and having a low intake of alcohol (OR = 2.40, 95% CI [1.13–5.11]) were risk factors for TST positivity, while living in the north zone (OR = 0.32, 95% CI [0.18–0.55]), living in the suburb zone (OR = 0.28, 95% CI [0.15–0.52]) and having a secondary education (OR = 0.49 95% CI [0.29–0.83]) lowered the risk of TST positivity. The generalized linear model showed that the previous predictors, as well as a low body mass index, had an effect on TST reaction size. The LTBI prevalence found in the population was moderate, reflecting the continuous transmission of M. tuberculosis. Social factors seem to play a decisive role in the risk of LTBI. Employed males, who are over 40 years of age, are overweight, have a lower level of education and have a low intake of alcohol (50–100 mL, once/week) should be a priority group for prophylactic treatment as a strategy for TB control in this city.

Low body mass index has minimal impact on plasma levels of cytokines and chemokines in tuberculous lymphadenitis

Malnutrition, due to low body mass index (LBMI), is considered to be one of the key risk factors for tuberculosis (TB) development. The link between pro and anti-inflammatory cytokines and BMI has been studied in active pulmonary TB. However, the association of BMI with cytokines and chemokines in TB lymphadenitis (TBL) has not been examined. Hence, we wanted to examine the plasma levels of different cytokines and chemokines in TBL individuals with LBMI, normal BMI (NBMI) and high BMI (HBMI). LBMI with TBL disease is associated with enhanced systemic levels of type 1 (tumor necrosis factor alpha [TNFα], interleukin-2 [IL-2]) and type 2 (IL-4, IL-13) cytokines in comparison with NBMI and/or HBMI. However, other pro-inflammatory (IFNγ, IL-1β, IL-17A, IL-6, IL-7, IL-12, G-CSF, and GM-CSF) and anti-inflammatory (IL-5 and IL-10) cytokines were not significantly different among the TBL individuals with different BMI status. Likewise, no significant differences were observed in the CC (CCL-1, CCL-2/MCP-1, CCL3/MIP1α, CCL4/MIP-1β, CCL11/eotaxin) and CXC (CXCL-1/GRO-⍺, CXCL2/GRO-β, CXCL9/MIG, CXCL10/IP-10, CXCL11/ITAC 1) chemokine profile among the TBL individuals with different BMI. Hence, our data implies that TBL individuals with LBMI are characterized by minimal effects on plasma cytokines and chemokines in TBL.

Evidence for a More Disrupted Immune-Endocrine Relation and Cortisol Immunologic Influences in the Context of Tuberculosis and Type 2 Diabetes Comorbidity

Pulmonary tuberculosis (PTB), caused by Mycobacterium tuberculosis (Mtb), is a major health problem worldwide, further aggravated by the convergence of type 2 diabetes mellitus (DM) which constitutes an important risk factor for TB development. The worse scenario of patients with PTB and DM may be partly related to a more unbalanced defensive response. As such, newly diagnosed PTB patients with DM (TB+DM, n = 11) or not (TB, n = 21), as well as DM (n = 18) patients and pair matched controls (Co, n = 22), were investigated for the circulating immuno-endocrine-metabolic profile (ELISA), along with studies in peripheral blood mononuclear cells (PBMC) analyzing transcript expression (RT-qPCR) of mediators involved in glucocorticoid functionality. Given the hyperglycemic/hypercortisolemic scenario of TB+DM patients, PBMC were also exposed to stress-related cortisol concentrations (0.1 and 1 μM) and supraphysiologic glucose doses (10, 20, and 40 mM) and assessed for the specific response against Mtb stimulation (lymphoproliferation, -thymidine incorporation-, and cytokine production -bead-cytometry). All TB patients displayed increased plasma amounts of cortisol, growth hormone -hGH-, and proinflammatory mediators. In turn, TB+DM showed even higher levels of interferon gamma -IFN-γ- and hGH (vs. TB), or IL-6, C reactive protein, cortisol and hGH (vs. DM). Both DM groups had equally augmented values of IL-10. All TB patients showed decreased dehydroepiandrosterone- sulfate concentrations, even more in TB+DM cases. Leptin was also decreased in both TB cases, particularly in the TB group, revealing a lower body mass index, as well. Unlike PBMC from TB cases showing a decreased relationship between the glucocorticoids receptor (GR) isoforms (GRα/GRβ; functional isoform/negative isoform), cells from TB+DM patients had no changes in this regard, along with an increased expression of 11-beta hydroxysteroid dehydrogenase type-1, the enzyme facilitating intracellular cortisone to cortisol conversion. TB+DM patients also showed an increased Mtb antigen-driven lymphoproliferation. Compared to TB, DM and HCo counterparts, PBMC from TB+DM patients had a biased Th1 response to Mtb stimulation (increased IL-2 and IFN-γ production), even when exposed to inhibitory cortisol doses. TB+DM patients show a more unbalanced immuno-endocrine relationship, respect the non-diabetic counterparts, with a relative deficiency of cortisol immunomodulatory influences, despite their more favorable microenvironment for cortisol-mediated immune effects.

Tuberculosis deaths are predictable and preventable: Comprehensive assessment and clinical care is the key

The goal of reducing tuberculosis (TB) mortality in the END TB Strategy can be achieved if TB deaths are considered predictable and preventable. This will require programs to examine and address some key gaps in the understanding of the distribution and determinants of TB mortality and the current model of assessment and care in high burden countries.

Most deaths in high-burden countries occur in the first eight weeks of treatment and in those belonging to the age group of 15–49 years, living in poverty, with HIV infection and/or low body mass index (BMI). Deaths result from extensive disease, comorbidities like advanced HIV disease complicated with other infections (bacterial, fungal, bloodstream), and moderate-severe undernutrition. Most early deaths in patients with TB, even with TB-HIV co-infection, are due to TB itself.

Comprehensive assessment and clinical care are a prerequisite of patient-centered care. Simple independent predictors of death like unstable vital signs, BMI, mid-upper arm circumference, or inability to stand or walk unaided can be used by programs for risk assessment. Programs need to define criteria for referral for inpatient care, address the paucity of hospital beds and develop and implement guidelines for the clinical management of seriously ill patients with TB, advanced HIV disease and severe undernutrition as co-morbidities. Programs should also consider notification and audit of all TB deaths, similar to audit of maternal deaths, and address the issues in delays in diagnosis, treatment, and quality of care.

High helminthic co-infection in tuberculosis patients with undernutritional status in northeastern Ethiopia

BACKGROUND

Tuberculosis and parasitosis are the widely distributed diseases in Ethiopia with the leading cause of mortality and morbidity, respectively. There has been no information on the status of co-infections of tuberculosis and parasitosis in Oromia Zone of Amhara Region and South Wollo, Ethiopia. Hence, this study primarily focuses on determining the status of tuberculosis and parasitosis co-infections and associated factors.

METHODS

The study was conducted in Oromia Special Zone of the Amhara Regional State and South Wollo Zone, northeastern Ethiopia from April 2015 to January 2017. Tuberculosis cases confirmed by health personnel at the health institutions were the source of the study sample. In a cross-sectional study 384 smear positive pulmonary and extra-pulmonary tuberculosis cases were recruited. Faecal specimens provided by the study participants were examined for parasitic co-infections using direct saline microscopic test, Kato-Katz and concentration techniques. Nutritional status was determined using body mass index and mid-upper arm circumferences. Data were analyzed using descriptive statistical methods and Pearson chi-square.

RESULTS

Tuberculosis and parasitosis co-infection prevalence was 10.8%, and the proportion of intestinal helminths accounted for 9.7% while intestinal protozoa accounted for 1.9%. Cases with single parasitic infection was 89.3% among co-infected individuals. Co-infection of both disease was not significantly associated with gender and age (P > 0.05). The prevalence of undernutrition was 58.6% as determined using body mass index and 73.0% as determined using mid-upper arm circumference with no significant association with gender. Among all forms of tuberculosis cases (384) screened for the study, the bacterial positivity was relatively more common in males (55.5%) than females (44.5%). Tuberculosis lymphadenitis was found to be the most prevalent (85.9%) form of extra-pulmonary tuberculosis with cervical adenopathy (75.3%) being the commonly existing disease.

CONCLUSIONS

The rate of helminthic co-infection is predominantly high than that of intestinal protozoa. Single parasitic co-infection was more common than double or multiple co-infections. Both body mass index and mid-upper arm circumference anthropometric parameters revealed greater risk of undernutrition in tuberculosis patients. Thus, screening and prompt treatment of parasites in tuberculosis patients and a support of nutritional supplementation for malnourished tuberculosis patients should be further studied which might enhance the disease treatment and minimize the risk of its complexity.

Tuberculosis and HIV co-infection in Congolese children: risk factors of death

Introduction

Human immunodeficiency virus (HIV) and tuberculosis (TB) are the leading causes of death from infectious disease worldwide. The prevalence of HIV among children with TB in moderate to high prevalence countries ranges between 10% and 60%. This study aimed to determine the prevalence of HIV infection among children treated for TB in Directly Observed Treatment Short-Course (DOTS) clinics in Lubumbashi and to identify risk of death during this co-infection.

Methods

This is a cross-sectional study of children under-15, treated for tuberculosis from January 1, 2013 to December 31, 2015. Clinical, paraclinical and outcome data were collected in 22 DOTS of Lubumbashi. A statistical comparison was made between dead and survived HIV-infected TB children. We performed the multivariate analyzes and the significance level set at p-value <0.05.

Results

A total of 840 children with TB were included. The prevalence of HIV infection was 20.95% (95% CI: 18.34-23.83%). The mortality rate was higher for HIV-infected children (47.73%) compared to HIV-uninfected children (17.02%) (p<0.00001). Age <5 years (aOR=6.50 [1.96-21.50]), a poor nutritional status (aOR=23.55 [8.20-67.64]), and a negative acid-fast bacilli testing (aOR=4.51 [1.08-18.70]) were associated with death during anti-TB treatment.

Conclusion

TB and HIV co-infection is a reality in pediatric settings in Lubumbashi. High mortality highlights the importance of early management.

M. tuberculosis infection and antigen specific cytokine response in healthcare workers frequently exposed to tuberculosis

Tuberculosis (TB) is the leading cause of death due to an infectious agent, but only a small fraction of those infected develop the disease. Cytokines are involved in the mediation and regulation of immunity, and their secretion patterns may reflect the infection status. To increase our understanding of immune response to M. tuberculosis infection, we conducted a cross-sectional study investigating M. tuberculosis infection status and comparing the release profiles of cytokines GM-CSF, IFN-γ, IL-1β, IL-10, IL-12 (p70), IL-2, IL-4, IL-5, IL-6, IL-8, TNF-α, in community controls (CCs) and healthy healthcare workers (HCWs) highly exposed to TB. Among HCWs and CCs, the probability of latent M. tuberculosis (LTB+) infection was respectively 5.4 (p = 0.002) and 3.4 (p = 0.006) times higher in men than women. The odds ratio of LTB infection was 4 times higher among HCWs in direct contact with active TB patients than other HCW (p = 0.01). Whole blood supernatant cytokine responses to M. tuberculosis antigens showed differential pro-inflammatory responses between HCWs and CCs. CCsLTB- had higher IL-1β responses than HCWsLTB- (p = 0.002). HCWsLTB+ had significantly higher IL-8 responses to M. tuberculosis antigens than HCWsLTB- (p = 0.003) and CCsLTB- (p = 0.015). HCWsLTB+/- showed weak but positive TNF-α responses to M. tuberculosis antigen stimulation compared to CCsLTB+/- (p ≤ 0.015). Looking at T-helper (1 and 2) responses, HCWsLTB+ and CCsLTB+ had significantly higher IFN-γ and IL-2 responses compared to HCWsLTB- and CCsLTB- (p < [0.0001-0.003]). Also, TB antigen induced IL-5 secretion was significantly higher in HCWsLTB+ and CCsLTB+ than in non-infected CCsLTB- (p < [0.005-0.04]). M. tuberculosis antigen specific responses in HCWsLTB+ varied based on active TB exposure gradient. HCWsLTB+ who were highly exposed to active TB (≥3 hours per day) had significantly higher IFN-γ and IL-8 responses (p ≤ 0.02) than HCWs LTB+ not in direct contact with active TB patients. HCWsLTB+ working with active TB patients for 5 to 31 years had a significantly enhanced secretion of proinflammatory cytokines (GM-CSF, IFN-γ, IL-1β, IL-2, IL-6, IL-8, IL-12p70, TNF-α) compared to HCWsLTB- (p < [0.0001-0.01]). Secretion of anti-inflammatory/Th2 cytokines IL-5 and IL-10 was also higher in HCWsLTB+ than HCWsLTB-. In conclusion, LTBI individuals controlling the M. tuberculosis infection have an enhanced TB specific Th1-cytokines/proinflammatory response combined with selected Th2 type/anti-inflammatory cytokines induction.

Host Transcriptomics as a Tool to Identify Diagnostic and Mechanistic Immune Signatures of Tuberculosis

Tuberculosis (TB) is a major infectious disease worldwide, and is associated with several challenges for control and eradication. First, more accurate diagnostic tools that better represent the spectrum of infection states are required; in particular, identify the latent TB infected individuals with high risk of developing active TB. Second, we need to better understand, from a mechanistic point of view, why the immune system is unsuccessful in some cases for control and elimination of the pathogen. Host transcriptomics is a powerful approach to identify both diagnostic and mechanistic immune signatures of diseases. We have recently reported that optimal study design for these two purposes should be guided by different sets of criteria. Here, based on already published transcriptomics signatures of tuberculosis, we further develop these guidelines and identify additional factors to consider for obtaining diagnostic vs. mechanistic signatures in terms of cohorts, samples, data generation and analysis. Diagnostic studies should aim to identify small disease signatures with high discriminatory power across all affected populations, and against similar pathologies to TB. Specific focus should be made on improving the diagnosis of infected individuals at risk of developing active disease. Conversely, mechanistic studies should focus on tissues biopsies, immune relevant cell subsets, state of the art transcriptomic techniques and bioinformatics tools to understand the biological meaning of identified gene signatures that could facilitate therapeutic interventions. Finally, investigators should ensure their data are made publicly available along with complete annotations to facilitate metadata and cross-study analyses.

Obesity Paradox in Advanced Kidney Disease: From Bedside to the Bench

While obesity is associated with a variety of complications including diabetes, hypertension, cardiovascular disease and premature death, observational studies have also found that obesity and increasing body mass index (BMI) can be linked with improved survival in certain patient populations, including those with conditions marked by protein-energy wasting and dysmetabolism that ultimately lead to cachexia. The latter observations have been reported in various clinical settings including end-stage renal disease (ESRD) and have been described as the "obesity paradox" or "reverse epidemiology", engendering controversy. While some have attributed the obesity paradox to residual confounding in an effort to "debunk" these observations, recent experimental discoveries provide biologically plausible mechanisms in which higher BMI can be linked to longevity in certain groups of patients. In addition, sophisticated epidemiologic methods that extensively adjusted for confounding have found that the obesity paradox remains robust in ESRD. Furthermore, novel hypotheses suggest that weight loss and cachexia can be linked to adverse outcomes including cardiomyopathy, arrhythmias, sudden death and poor outcomes. Therefore, the survival benefit observed in obese ESRD patients can at least partly be derived from mechanisms that protect against inefficient energy utilization, cachexia and protein-energy wasting. Given that in ESRD patients, treatment of traditional risk factors has failed to alter outcomes, detailed translational studies of the obesity paradox may help identify innovative pathways that can be targeted to improve survival. We have reviewed recent clinical evidence detailing the association of BMI with outcomes in patients with chronic kidney disease, including ESRD, and discuss potential mechanisms underlying the obesity paradox with potential for clinical applicability.

A comparative study of the socio-economic risk factors for pulmonary tuberculosis in the Saharia tribe of Madhya Pradesh, India

Background

To determine the socio-economic risk factors for pulmonary tuberculosis (PTB) in the Saharia tribal community in Madhya Pradesh, Central India.

Methods

PTB cases detected during the year 2013-14 through a community active TB prevalence survey in the Shivpuri district, Madhya Pradesh were included in the study. For each case, three controls were selected randomly among the non-cases from the same village and the data on socio-economic risk factors were collected. Using logistic regression analysis, the risk factors for PTB disease were identified.

Results

A total of 220 cases and 660 controls participated in the study. Of the 13 risk factors studied, on multivariate analysis the risk of PTB was found to be significantly associated with malnutrition (adjusted odds ratio [AOR] 2.02 [95% confidence interval {CI} 1.46 to 2.79]), living in a kaccha (built of naturally occurring materials) house (AOR 2.72 [95% CI 1.44 to 5.11]) and tobacco smoking (mostly beedis; AOR 1.59 [95% CI 1.12 to 2.18]).

Conclusions

The findings highlight that malnutrition, poor living conditions in a Kaccha house (built of naturally occurring materials) and tobacco smoking are the major risk factors for PTB among Saharias, which need to be studied among other tribal populations in the country. There is a need to strengthen health and nutrition programmes in this community.

Plasma Indoleamine 2, 3-Dioxygenase, a Biomarker for Tuberculosis in Human Immunodeficiency Virus-Infected Patients

Background

There is no biomarker for diagnosing active tuberculosis in patients with human immunodeficiency virus (HIV) infection. Indoleamine 2, 3-dioxygenase (IDO) is an immunoregulatory enzyme that breaks down tryptophan (Trp) to metabolites known as kynurenines (Kyns). We investigated whether IDO activity, as measured by the ratio of Kyn to Trp, could be used to diagnose or predict active tuberculosis disease in HIV-infected adults.

Methods

Kyn and Trp concentrations were measured using ultraperformance liquid chromatography mass spectrometry in plasma samples from 32 HIV-infected patients in whom active tuberculosis developed and who were followed up prospectively. We compared to 70 HIV-infected control subjects from the same cohort in whom tuberculosis did not develop, matched by age, sex, and CD4 cell count, and 37 unmatched HIV-infected patients with a diagnosis of pneumonia. Clinical parameters, including body mass index, CD4 cell count, HIV load, and C-reactive protein levels were analyzed.

Results

At the time of tuberculosis diagnosis, IDO activity was significantly higher in patients with tuberculosis than in controls (P < .001). Six months before tuberculosis diagnosis, IDO activity was significantly higher in all patients who later developed tuberculosis (P < .001) than controls. After 6 months of tuberculosis treatment, IDO activity in patients with tuberculosis declined to levels similar to those in controls. IDO activity was 4-fold higher in patients with tuberculosis than in those with pneumonia, and could be used to distinguish them. With a receiver operating characteristic curve, IDO activity had a sensitivity of 97%, a specificity of 99%, and positive and negative predictive values of 89% and 100% for detecting active tuberculosis disease.

Conclusion

Plasma IDO activity is suitable as a biomarker of active tuberculosis in HIV-positive patients.

Formation of Foamy Macrophages by Tuberculous Pleural Effusions Is Triggered by the Interleukin-10/Signal Transducer and Activator of Transcription 3 Axis through ACAT Upregulation

The ability of Mycobacterium tuberculosis (Mtb) to persist in its human host relies on numerous immune evasion strategies, such as the deregulation of the lipid metabolism leading to the formation of foamy macrophages (FM). Yet, the specific host factors leading to the foamy phenotype of Mtb-infected macrophages remain unknown. Herein, we aimed to address whether host cytokines contribute to FM formation in the context of Mtb infection. Our approach is based on the use of an acellular fraction of tuberculous pleural effusions (TB-PE) as a physiological source of local factors released during Mtb infection. We found that TB-PE induced FM differentiation as observed by the increase in lipid bodies, intracellular cholesterol, and expression of the scavenger receptor CD36, as well as the enzyme acyl CoA:cholesterol acyl transferase (ACAT). Importantly, interleukin-10 (IL-10) depletion from TB-PE prevented the augmentation of all these parameters. Moreover, we observed a positive correlation between the levels of IL-10 and the number of lipid-laden CD14⁺ cells among the pleural cells in TB patients, demonstrating that FM differentiation occurs within the pleural environment. Downstream of IL-10 signaling, we noticed that the transcription factor signal transducer and activator of transcription 3 was activated by TB-PE, and its chemical inhibition prevented the accumulation of lipid bodies and ACAT expression in macrophages. In terms of the host immune response, TB-PE-treated macrophages displayed immunosuppressive properties and bore higher bacillary loads. Finally, we confirmed our results using bone marrow-derived macrophage from IL-10^-/- mice demonstrating that IL-10 deficiency partially prevented foamy phenotype induction after Mtb lipids exposure. In conclusion, our results evidence a role of IL-10 in promoting the differentiation of FM in the context of Mtb infection, contributing to our understanding of how alterations of the host metabolic factors may favor pathogen persistence.

Factors associated with sputum culture conversion in patients with pulmonary tuberculosis

OBJECTIVE

The aim of this study was to determine what factors are associated with sputum culture conversion after 1 month of tuberculosis (TB) treatment.

MATERIALS AND METHODS

A total of 52 patients with new drug susceptible pulmonary TB were included in the study. Patients completed St. George respiratory questionnaire (SGRQ), they were asked about smoking, alcohol use, living conditions and education. Body mass index (BMI) measurements, laboratory tests (C reactive protein [CRP], vitamin D, albumin) were performed, and chest X-ray was done. After 1 month of treatment sputum culture was repeated.

RESULTS

Culture conversion after 1 month of treatment was found in 38.5% cases. None of investigated social factors appeared to have an effect on conversion, but worse overall health status (as reported in SGRQ) and longer duration of tobacco smoking were detected in the "no conversion" group. Concentrations of albumin, CRP, X-ray score and the time it took Mycobacterium tuberculosis culture to grow also differed. Patients who scored 30 or more on SGRQ were more than 7 times as likely to have no conversion. However, the most important factor predicting sputum culture conversion was sputum smear grade at the beginning of treatment: patients with grade of 2+ or more had more than 20-fold higher relative risk for no conversion. Using receiver operating characteristic curve analysis, we also developed a risk score for no conversion.

CONCLUSIONS

The most important factors in predicting sputum culture conversion after 1 month of treatment were grades of acid-fast bacilli in sputum smears at time of diagnosis and scores of SGRQ.

Immunological non-response and low hemoglobin levels are predictors of incident tuberculosis among HIV-infected individuals on Truvada-based therapy in Botswana

Background

There is a high burden of tuberculosis (TB) in HIV antiretroviral programmes in Africa. However, few studies have looked at predictors of incident TB while on Truvada-based combination antiretroviral therapy (cART) regimens.

Methods

We estimated TB incidence among individuals enrolled into an observational cohort evaluating the efficacy and tolerability of Truvada-based cART in Gaborone, Botswana between 2008 and 2011. We used Cox proportional hazards regressions to determine predictors of incident TB.

Results

Of 300 participants enrolled, 45 (15%) had a diagnosis of TB at baseline. During 428 person-years (py) of follow-up, the incidence rate of TB was 3.04/100py (95% CI, 1.69–5.06), with 60% of the cases occurring within 3 months of ART initiation. Incident cases had low baseline CD4+ T cell counts (153cells/mm³ [Q1, Q3: 82, 242]; p = 0.69) and hemoglobin levels (9.2g/dl [Q1, Q3: 8.5,10.1]; p<0.01). In univariate analysis, low BMI (HR = 0.73; 95% CI 0.58–0.91; p = 0.01) and hemoglobin levels <8 g/dl (HR = 10.84; 95%CI: 2.99–40.06; p<0.01) were risk factors for TB. Time to incident TB diagnosis was significantly reduced in patients with poor immunological recovery (p = 0.04). There was no association between baseline viral load and risk of TB (HR = 1.75; 95%CI: 0.70–4.37).

Conclusion

Low hemoglobin levels prior to initiation of ART are significant predictors of incident tuberculosis. Therefore, there is potential utility of iron biomarkers to identify patients at risk of TB prior to initiation on ART. Furthermore, additional strategies are required for patients with poor immunological recovery to reduce excess risk of TB while on ART.

Metformin Use Reverses the Increased Mortality Associated With Diabetes Mellitus During Tuberculosis Treatment

Background

The global type 2 diabetes mellitus (DM) epidemic threatens progress made in reducing tuberculosis (TB)-related mortality worldwide. Previous clinical studies have not fully evaluated potential confounding variables in addressing the impact of DM on TB treatment outcomes. The antidiabetic agent metformin regulates autophagy and may play a role as a host-directed therapeutic adjuvant to antitubercular treatment.

Methods

We conducted a retrospective cohort study comprising patients aged ≥13 years undergoing treatment for culture-confirmed, drug-susceptible pulmonary TB. We assessed the effect of DM on mortality during TB treatment and 2-month TB sputum-culture conversion. We also evaluated the effect of metformin use on survival during TB treatment.

Results

Among 2416 patients undergoing TB treatment, after adjusting for age, sex, chronic kidney disease, cancer, hepatitis C, tobacco use, cavitary disease, and treatment adherence, patients with DM had 1.91 times higher odds (95% confidence interval [CI], 1.51-2.40) of death during TB treatment than patients without DM, and 1.72 (95% CI, 1.25-2.38) times higher odds of remaining culture-positive at 2 months. Metformin use in patients with DM was significantly associated with decreased mortality during TB treatment (hazard ratio, 0.56 [95% CI, .39-.82]), and metformin users had similar mortality as patients without DM.

Conclusions

This study suggests that despite multiple potential confounding variables, DM poses an increased risk of adverse TB treatment outcomes. There was a significant association between metformin use and decreased mortality during TB treatment, suggesting a potential role for this agent as adjunctive, host-directed therapy.

Underweight increases the risk of early death in tuberculosis patients

Evidence regarding the association between BMI and mortality in tuberculosis (TB) patients is limited and inconsistent. We investigated the impact of BMI on TB-specific and non-TB-specific mortality with respect to different timing of death. All Taiwanese adults with TB in Taipei were included in a retrospective cohort study in 2012-2014. Multinomial Cox proportional hazards regression was used to evaluate the associations between BMI, cause-specific mortality and timing of death. Of 2410 eligible patients, 86·0 % (2061) were successfully treated, and TB-specific and non-TB-specific mortality occurred for 2·2 % (54) and 13·9 % (335), respectively. After controlling for potential confounders, underweight was significantly associated with a higher risk of all-cause mortality (adjusted hazard ratio (AHR) 1·57; 95 % CI 1·26, 1·95), whereas overweight was not. When cause-specific death was considered, underweight was associated with an increased risk of either TB-specific (AHR 1·85; 95 % CI 1·03, 3·33) or non-TB-specific death (AHR 1·52; 95 % CI 1·19, 1·95) during treatment. With joint consideration of cause-specific and timing of death, underweight only significantly increased the risk of TB-specific (AHR 2·23; 95 % CI 1·09, 4·59) and non-TB-specific mortality (AHR 1·81; 95 % CI 1·29, 2·55) within the first 8 weeks of treatment. This study suggests that underweight increases the risk of early death in TB patients during treatment.

Mycobacterium tuberculosis infection modulates adipose tissue biology

Mycobacterium tuberculosis (Mtb) primarily resides in the lung but can also persist in extrapulmonary sites. Macrophages are considered the prime cellular habitat in all tissues. Here we demonstrate that Mtb resides inside adipocytes of fat tissue where it expresses stress-related genes. Moreover, perigonadal fat of Mtb-infected mice disseminated the infection when transferred to uninfected animals. Adipose tissue harbors leukocytes in addition to adipocytes and other cell types and we observed that Mtb infection induces changes in adipose tissue biology depending on stage of infection. Mice infected via aerosol showed infiltration of inducible nitric oxide synthase (iNOS) or arginase 1 (Arg1)-negative F4/80⁺ cells, despite recruitment of CD3⁺, CD4⁺ and CD8⁺ T cells. Gene expression analysis of adipose tissue of aerosol Mtb-infected mice provided evidence for upregulated expression of genes associated with T cells and NK cells at 28 days post-infection. Strikingly, IFN-γ-producing NK cells and Mtb-specific CD8⁺ T cells were identified in perigonadal fat, specifically CD8⁺CD44^-CD69⁺ and CD8⁺CD44^-CD103⁺ subpopulations. Gene expression analysis of these cells revealed that they expressed IFN-γ and the lectin-like receptor Klrg1 and down-regulated CD27 and CD62L, consistent with an effector phenotype of Mtb-specific CD8⁺ T cells. Sorted NK cells expressed higher abundance of Klrg1 upon infection, as well. Our results reveal the ability of Mtb to persist in adipose tissue in a stressed state, and that NK cells and Mtb-specific CD8⁺ T cells infiltrate infected adipose tissue where they produce IFN-γ and assume an effector phenotype. We conclude that adipose tissue is a potential niche for Mtb and that due to infection CD8⁺ T cells and NK cells are attracted to this tissue.

In 2015, tuberculosis (TB) affected 10.4 million individuals causing 1.8 million deaths per year. Yet, a much larger group– 2 billion people–harbors latent TB infection (LTBI) without clinical symptoms, but at lifelong risk of reactivation. The physiological niches of Mycobacterium tuberculosis (Mtb) persistence remain incompletely defined and both pulmonary and extrapulmonary sites have been proposed. Adipose tissue constitutes 15–25% of total body mass and is an active production site for hormones and inflammatory mediators. The increasing prevalence of obesity, has led to greater incidence of type 2 diabetes. These patients suffer from three times higher risk of developing TB, pointing to a potential link between adipose tissue and TB pathogenesis. In individuals with LTBI, Mtb survives in a stressed, non-replicating state with low metabolic activity and resting macrophages serve as preferred habitat and become effectors after appropriate stimulation. Here we demonstrate that Mtb can infect and persist within adipocytes where it upregulates stress-related genes. In vivo, relative proportions of leukocyte subsets infiltrating adipose tissue varied under different conditions of infection. During natural aerosol Mtb infection, distinct leukocyte subsets, including mononuclear phagocytes, Mtb-specific CD8⁺ T cells and NK cells infiltrated adipose tissue and became activated. Thus, our study shows that adipose tissue is not only a potential reservoir for this pathogen but also undergoes significant alteration during TB infection.

Small Molecule Mediated Restoration of Mitochondrial Function Augments Anti-Mycobacterial Activity of Human Macrophages Subjected to Cholesterol Induced Asymptomatic Dyslipidemia

Mycobacterium tuberculosis (M.tb) infection manifests into tuberculosis (TB) in a small fraction of the infected population that comprises the TB susceptible group. Identifying the factors potentiating susceptibility to TB persistence is one of the prime agenda of TB control programs. Recently, WHO recognized diabetes as a risk factor for TB disease progression. The closely related pathological state of metabolic imbalance, dyslipidemia, is yet another emerging risk factor involving deregulation in host immune responses. While high cholesterol levels are clinically proven condition for perturbations in cardiac health, a significant fraction of population these days suffer from borderline risk cholesterol profiles. This apparently healthy population is susceptible to various health risks placing them in the "pre-disease" range. Our study focuses on determining the role of such asymptomatic dyslipidemia as a potential risk factor for susceptibility to TB persistence. Macrophages exposed to sub-pathological levels of cholesterol for chronic period, besides impaired release of TNF-α, could not clear intracellular pathogenic mycobacteria effectively as compared to the unexposed cells. These cells also allowed persistence of opportunistic mycobacterial infection by M. avium and M. bovis BCG, indicating highly compromised immune response. The cholesterol-treated macrophages developed a foamy phenotype with a significant increase in intracellular lipid-bodies prior to M.tb infection, potentially contributing to pre-disease state for tuberculosis infection. The foamy phenotype, known to support M.tb infection, increased several fold upon infection in these cells. Additionally, mitochondrial morphology and function were perturbed, more so during infection in cholesterol treated cells. Pharmacological supplementation with small molecule M1 that restored mitochondrial structural and functional integrity limited M.tb survival more effectively in cholesterol exposed macrophages. Mechanistically, M1 molecule promoted clearance of mycobacteria by reducing total cellular lipid content and restoring mitochondrial morphology and function to its steady state. We further supported our observations by infection assays in PBMC-derived macrophages from clinically healthy volunteers with borderline risk cholesterol profiles. With these observations, we propose that prolonged exposure to sub-pathological cholesterol can lead to asymptomatic susceptibility to M.tb persistence. Use of small molecules like M1 sets yet another strategy for host-directed therapy where re-functioning of mitochondria in cholesterol abused macrophages can improve M.tb clearance.

Impact of obesity on antiretroviral pharmacokinetics and immuno-virological response in HIV-infected patients: a case-control study

Background

Obesity has high prevalence among HIV-infected patients. Increased adipose tissue mass affects the pharmacokinetics of numerous drugs, but few data are available for antiretroviral drugs.

Objectives

In this study we aimed to explore the pharmacokinetics of antiretroviral drugs and the immuno-virological response in obese patients with HIV infection.

Patients and methods

We examined data from 2009 to 2012 in our hospital's database for HIV-1-infected patients who received an antiretroviral drug (abacavir, emtricitabine, lamivudine, tenofovir, efavirenz, etravirine, nevirapine, atazanavir/ritonavir, darunavir/ritonavir, lopinavir/ritonavir or raltegravir). Obese patients were defined as those with BMI ≥30 kg/m 2 and normal-weight patients as those with BMI 19-25 kg/m 2 . Plasma concentrations ( C 12/24 ) were compared for each antiretroviral drug using a Mann-Whitney test. Suboptimal dosing and virological outcome were assessed by logistic regression, adjusting on covariates.

Results

We enrolled 291 obese and 196 normal-weight patients. Among the 12 analysed antiretroviral drugs, tenofovir, efavirenz and lopinavir C 12 values were significantly lower in obese than normal-weight patients: 66 versus 86 ng/mL, 1498 versus 2034 ng/mL and 4595 versus 6420 ng/mL, respectively ( P  <   0.001). Antiretroviral drug C 12/24 values were more frequently below efficacy thresholds for obese than for normal-weight patients after adjustment for other covariates ( P  <   0.001). Although obese patients showed a higher CD4 count than normal-weight patients (510 versus 444 cells/mm 3 , P  <   0.001), the groups did not differ in virological failure rate.

Conclusions

This study highlights the impact of obesity on antiretroviral drug plasma exposure, but identifies no consequence of this suboptimal exposure on the immuno-virological control in this population.

Factors associated with pulmonary impairment in HIV-infected South African adults

Background

HIV-infected individuals have increased risk of developing obstructive lung disease (OLD). Studies from developed countries report high viral load, low CD4 counts, and anti-retroviral therapy (ART) to be associated with OLD; but these findings may not be generalizable to populations in resource-limited settings.

Methods

We conducted a prospective cohort study of lung function in 730 HIV-infected black South African adults. Pre-bronchodilator spirometry was performed at enrollment and repeated annually for three years. Logistic regression models were used to identify factors associated with OLD, defined as FEV1/FVC<0.70, at enrollment. Excess annual declines in FEV1 and FVC were modelled as the product-term of follow-up time and exposures using random effects regression.

Results

Median (IQR) age at enrollment was 36 (32–41) years, 85% were female and 30% ever-smoked with a median (IQR) exposure of 3 (1–6) pack-years. Median (IQR) CD4 count and viral load at enrollment were 372 (261–518) cells/mm³ and 2655 (91–13,548) copies/mL respectively. Overall, 25% were receiving ART at enrollment, 16% of whom reported at least 6 months of ART receipt. OLD was found in 35 (5%) at enrollment. Increasing age (aOR = 2.08 per 10-years [95%CI 1.22–3.57], p = 0.007), current smoking (aOR = 3.55 [95%CI 1.20–10.53], p = 0.02), and CRP (aOR = 1.01 per unit-increase [95%CI 1.00–1.03], p = 0.04) were significantly associated with OLD at enrollment; while increasing CD4 count (aOR = 1.02 per-100 cells/mm³ [95%CI 0.85–1.22], p = 0.82), viral load (aOR = 0.67 per log-increase [95%CI 0.43–1.10], p = 0.12) and receipt of ART (aOR = 0.57 [95%CI 0.18–1.75], p = 0.32) were not. The median (IQR) follow-up time was 18 (12–24) months. Participants with a history of tuberculosis (TB) had a 35 mL (95%CI 2–68, p = 0.03) and 57 mL (95%CI 19–96, p = 0.003) per year excess loss of FEV1 and FVC respectively.

Conclusion

Prevalent OLD was associated with older age, current smoking and higher CRP levels, but not CD4 counts and ART, in HIV-infected South African adults. Better understanding of the long-term effects of TB, smoking and inflammation on lung function in HIV-infected populations is urgently needed.

Mycobacterium bovis BCG and New Vaccines for the Prevention of Tuberculosis

Tuberculosis infects millions of people worldwide and remains a leading global killer despite widespread neonatal administration of the tuberculosis vaccine, bacillus Calmette-Guérin (BCG). BCG has clear and sustained efficacy, but after 10 years, its efficacy appears to wane, at least in some populations. Fortunately, there are many new tuberculosis vaccines in development today, some in advanced stages of clinical trial testing. Here we review the epidemiological need for tuberculosis vaccination, including evolving standards for administration to at risk individuals in developing countries. We also examine proven sources of immune protection from tuberculosis, which to date have exclusively involved natural or vaccine exposure to whole cell mycobacteria. After summarizing evidence for the use and efficacy of BCG, we detail the most promising new candidate vaccines against tuberculosis. The global need for a new tuberculosis vaccine is acute and huge, but clinical trials to be completed in the coming few years are likely either to identify a new tuberculosis vaccine or to substantially reframe how we understand immune protection from this historical scourge.

A clinical scoring system to prioritise investigation for tuberculosis among adults attending HIV clinics in South Africa

Background

The World Health Organization (WHO) recommendation for regular tuberculosis (TB) screening of HIV-positive individuals with Xpert MTB/RIF as the first diagnostic test has major resource implications.

Objective

To develop a diagnostic prediction model for TB, for symptomatic adults attending for routine HIV care, to prioritise TB investigation.

Design

Cohort study exploring a TB testing algorithm.

Setting

HIV clinics, South Africa.

Participants

Representative sample of adult HIV clinic attendees; data from participants reporting ≥1 symptom on the WHO screening tool were split 50:50 to derive, then internally validate, a prediction model.

Outcome

TB, defined as “confirmed” if Xpert MTB/RIF, line probe assay or M. tuberculosis culture were positive; and “clinical” if TB treatment started without microbiological confirmation, within six months of enrolment.

Results

Overall, 79/2602 (3.0%) participants on ART fulfilled TB case definitions, compared to 65/906 (7.2%) pre-ART. Among 1133/3508 (32.3%) participants screening positive on the WHO tool, 1048 met inclusion criteria for this analysis: 52/515 (10.1%) in the derivation and 58/533 (10.9%) in the validation dataset had TB. Our final model comprised ART status (on ART > 3 months vs. pre-ART or ART < 3 months); body mass index (continuous); CD4 (continuous); number of WHO symptoms (1 vs. >1 symptom). We converted this to a clinical score, using clinically-relevant CD4 and BMI categories. A cut-off score of ≥3 identified those with TB with sensitivity and specificity of 91.8% and 34.3% respectively. If investigation was prioritised for individuals with score of ≥3, 68% (717/1048) symptomatic individuals would be tested, among whom the prevalence of TB would be 14.1% (101/717); 32% (331/1048) of tests would be avoided, but 3% (9/331) with TB would be missed amongst those not tested.

Conclusion

Our clinical score may help prioritise TB investigation among symptomatic individuals.

Tea Drinking and Its Association with Active Tuberculosis Incidence among Middle-Aged and Elderly Adults: The Singapore Chinese Health Study

Experimental studies showed that tea polyphenols may inhibit growth of Mycobacterium tuberculosis. However, no prospective epidemiologic study has investigated tea drinking and the risk of active tuberculosis. We investigated this association in the Singapore Chinese Health Study, a prospective population-based cohort of 63,257 Chinese aged 45–74 years recruited between 1993 and 1998 in Singapore. Information on habitual drinking of tea (including black and green tea) and coffee was collected via structured questionnaires. Incident cases of active tuberculosis were identified via linkage with the nationwide tuberculosis registry up to 31 December 2014. Cox proportional hazard models were used to estimate the relation of tea and coffee consumption with tuberculosis risk. Over a mean 16.8 years of follow-up, we identified 1249 incident cases of active tuberculosis. Drinking either black or green tea was associated with a dose-dependent reduction in tuberculosis risk. Compared to non-drinkers, the hazard ratio (HR) (95% confidence interval (CI)) was 1.01 (0.85–1.21) in monthly tea drinkers, 0.84 (0.73–0.98) in weekly drinkers, and 0.82 (0.71–0.96) in daily drinkers (p for trend = 0.003). Coffee or caffeine intake was not significantly associated with tuberculosis risk. In conclusion, regular tea drinking was associated with a reduced risk of active tuberculosis.

Effect of DOTS Treatment on Vitamin D Levels in Pulmonary Tuberculosis

INTRODUCTION

Vitamin D (Vit D) modulates a variety of processes and regulatory systems including host defense, inflammation, immunity, and repair. Vit D Deficiency (VDD) is been implicated as a cause in diabetes, immune dysfunction and Tuberculosis (TB). Impaired metabolism of Vit D and an adverse outcome is associated with Pulmonary Tuberculosis (PTB). Directly Observed Treatment Short Course (DOTS) consist of drugs like rifampicin and isoniazid, which respectively cause accelerated loss of Vit D due to increased clearance and impairment of 25-hydroxylation causing diminished Vit D action.

AIM

The aim of the present study was to estimate and compare serum Vit D status in newly diagnosed PTB patients before and after DOTS to validate the supplementation of Vit D in PTB patients.

MATERIALS AND METHODS

Forty four newly diagnosed PTB patients of both the sexes in the age group of 18 to 60 years before starting DOTS were recruited to participate in this non- randomized controlled trial with their voluntary consent. Vit D status in these patients and the effect of DOTS on Vit D were evaluated.

RESULTS

Mean Vit D levels of the study population aged 43±13 years was 20.74 ng/ml (normal >30 ng/ml) at the time of diagnosis. After completion of six months of therapy mean Vit D reduced to 17.49 ng/ml (p-value=0.041). On individual observations, 70% of the participants showed a decrease in Vit D levels from their baseline, whereas 30% showed an increase. Comparison between the two groups indicated the possible role of younger age in the improved status.

CONCLUSION

VDD was seen in PTB patients, which worsened in majority of the study population after treatment; hence it would be advisable to recommend Vit D supplementation in PTB patients for a better outcome.