Body Mass Index, Diabetes, and Risk of Tuberculosis: A Retrospective Cohort Study

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.

Colliding Challenges: An Analysis of SARS-CoV-2 Infection in Patients with Pulmonary Tuberculosis versus SARS-CoV-2 Infection Alone

Background and Objectives: The concurrent occurrence of tuberculosis and COVID-19 coinfection poses significant clinical complexities, warranting a nuanced approach to diagnosis, management, and patient care. Materials and Methods: A retrospective, cross-sectional study was conducted on two groups: one comprising 32 patients with pulmonary TB (PTB) and COVID-19 co-infection, and one including 100 patients with COVID-19 alone. Data was collected from medical records, including patient history, clinical parameters, laboratory, imaging results, and patient outcome. Results: A lower BMI emerges as a significant marker suggesting underlying PTB in patients with SARS-CoV-2 co-infection. Type 2 diabetes mellitus increases the risk of death in PTB-SARS-CoV-2 co-infection. Co-infected patients show lymphocytopenia and higher neutrophil levels, CRP, transaminases, and D-dimer levels. Elevated CRP and ALT levels are linked to increased co-infection likelihood. Certain parameters like SpO2, CRP, ALT, AST, and D-dimer effectively differentiate between co-infected and COVID-19 patients. Platelet-to-lymphocyte ratio is notably higher in co-infected individuals. Lesion severity on imaging is significantly associated with co-infection, highlighting imaging's diagnostic importance. Longer hospital stays are linked to co-infection but not significantly to death risk. Conclusions: Certain clinical and biological factors may serve as potential indicators of PTB co-infection in patients with SARS-CoV-2.

Pulmonary tuberculosis epidemiology and genetics in Kazakhstan

Background

Tuberculosis (TB) is a major public health emergency in many countries, including Kazakhstan. Despite the decline in the incidence rate and having one of the highest treatment effectiveness in the world, the incidence rate of TB remains high in Kazakhstan. Social and environmental factors along with host genetics contribute to pulmonary tuberculosis (PTB) incidence. Due to the high incidence rate of TB in Kazakhstan, our research aimed to study the epidemiology and genetics of PTB in Kazakhstan.

Materials and methods

1,555 participants were recruited to the case-control study. The epidemiology data was taken during an interview. Polymorphisms of selected genes were determined by real-time PCR using pre-designed TaqMan probes.

Results

Epidemiological risk factors like diabetes (χ2 = 57.71, p < 0.001), unemployment (χ2 = 81.1, p < 0.001), and underweight-ranged BMI (<18.49, χ2 = 206.39, p < 0.001) were significantly associated with PTB. VDR FokI (rs2228570) and VDR BsmI (rs1544410) polymorphisms were associated with an increased risk of PTB. A/A genotype of the TLR8 gene (rs3764880) showed a significant association with an increased risk of PTB in Asians and Asian males. The G allele of the rs2278589 polymorphism of the MARCO gene increases PTB susceptibility in Asians and Asian females. VDR BsmI (rs1544410) polymorphism was significantly associated with PTB in Asian females. A significant association between VDR ApaI polymorphism and PTB susceptibility in the Caucasian population of Kazakhstan was found.

Conclusion

This is the first study that evaluated the epidemiology and genetics of PTB in Kazakhstan on a relatively large cohort. Social and environmental risk factors play a crucial role in TB incidence in Kazakhstan. Underweight BMI (<18.49 kg/m2), diabetes, and unemployment showed a statistically significant association with PTB in our study group. FokI (rs2228570) and BsmI (rs1544410) polymorphisms of the VDR gene can be used as possible biomarkers of PTB in Asian males. rs2278589 polymorphism of the MARCO gene may act as a potential biomarker of PTB in Kazakhs. BsmI polymorphism of the VDR gene and rs2278589 polymorphism of the MARCO gene can be used as possible biomarkers of PTB risk in Asian females as well as VDR ApaI polymorphism in Caucasians.

Tuberculosis prevalence and demographic characteristics of population in Azad Jammu and Kashmir (Pakistan): A retrospective study

Tuberculosis (TB) remains a serious problem for public health and a leading cause of death after COVID-19 and superior to even HIV/AIDS. It is a social health issue and can cause stigma and economic loss as the person cannot perform professionally due to lethargy caused by disease. It is a retrospective study done on data from National TB program Muzaffarabad chapter. The details were noted on SPSS and analysis was done to find important demographic characteristics. The total number of patients was 3441; among which 48.76% were males. Most of them (81.11%) belonged to the Muzaffarabad division of Azad Jammu and Kahmir (AJK). The microbiologically or culture positive cases were 440. Rifampicin resistance was present in 147 cases, further categorized as high (n = 143), very high (n = 3), or true positive (n = 1) resistance. Muti drug resistance was found in 19 cases. The microscopy culture is more sensitive (AUC = 0.511) than MTB/RIF or serology (AUC = 0.502) according to ROC. The rate of positive smear results is not very satisfactory in the present study as it cannot detect dormant or latent cases. There is a need to establish more sensitive tests for detection of cases and more research to combat the disease.

Increased Risk of Incident Chronic Obstructive Pulmonary Disease and Related Hospitalizations in Tuberculosis Survivors: A Population-Based Matched Cohort Study

BACKGROUND

Tuberculosis (TB) survivors have an increased risk of developing chronic obstructive pulmonary disease (COPD). This study assessed the risk of COPD development and COPD-related hospitalization in TB survivors compared to controls.

METHODS

We conducted a population-based cohort study of TB survivors and 1:1 age- and sex-matched controls using data from the Korean National Health Insurance Service database collected from 2010 to 2017. We compared the risk of COPD development and COPD-related hospitalization between TB survivors and controls.

RESULTS

Of the subjects, 9.6% developed COPD, and 2.8% experienced COPD-related hospitalization. TB survivors had significantly higher COPD incidence rates (36.7/1,000 vs. 18.8/1,000 person-years, P < 0.001) and COPD-related hospitalization (10.7/1,000 vs. 4.3/1,000 person-years, P < 0.001) than controls. Multivariable Cox regression analyses revealed higher risks of COPD development (adjusted hazard ratio [aHR], 1.63; 95% confidence interval [CI], 1.54-1.73) and COPD-related hospitalization (aHR, 2.03; 95% CI, 1.81-2.27) in TB survivors. Among those who developed COPD, the hospitalization rate was higher in individuals with post-TB COPD compared to those with non-TB COPD (10.7/1,000 vs. 4.9/1,000 person-years, P < 0.001), showing an increased risk of COPD-related hospitalization (aHR, 1.84; 95% CI, 1.17-2.92).

CONCLUSION

TB survivors had higher risks of incident COPD and COPD-related hospitalization compared to controls. These results suggest that previous TB is an important COPD etiology associated with COPD-related hospitalization.

Vitamin D Status, VDR, and TLR Polymorphisms and Pulmonary Tuberculosis Epidemiology in Kazakhstan

BACKGROUND

Tuberculosis (TB) and vitamin D deficiency remain major public health problems in Kazakhstan. Due to the high incidence of pulmonary tuberculosis in the country and based on the importance of vitamin D in the modulation of the immune response and the association of its deficiency with many health conditions, the aim of our research was to study the vitamin D status, VDR and TLR gene polymorphisms, and pulmonary tuberculosis epidemiology in Kazakhstan.

METHODS

A case-control study included 411 individuals diagnosed with pulmonary TB and 686 controls with no family history of pulmonary tuberculosis. Concentrations of serum vitamin D (25-(OH)D) levels were measured by electrochemiluminescence immunoassay. The gene polymorphisms were determined by real-time polymerase chain reaction (PCR) allelic discrimination assay using TaqMan probes. The association between the risk of pulmonary TB and polymorphisms was evaluated using multimodal logistic regression and assessed with the ORs, corresponding to 95% Cis, and the significance level was determined as p < 0.05.

RESULTS

1097 individuals were recruited from 3 different regions of Kazakhstan. Biochemical data showed vitamin D deficiency (25-(OH)D < 20 ng/mL) was present in both groups, with the case group accounting for almost 95% and 43.7% in controls. Epidemiological data revealed that socioeconomic factors such as BMI < 25 kg/m2 (p < 0.001), employment (p < 0.001), diabetes (p < 0.001), and vitamin D deficiency (p < 0.001) were statistically different between case and control groups. Logistic regression analysis, adjusted by sex, age, BMI, residence, employment, smoking, alcohol consumption, and diabetes, showed that T/T polymorphism of the VDR gene (rs1544410, OR = 1.97, 95% CI: 1.04-3.72, p = 0.03) and A/A polymorphism of the TLR8 gene (rs3764880, OR = 2.44, 95% CI: 1.20-4.98, p = 0.01) were associated with a high risk of developing pulmonary tuberculosis.

CONCLUSIONS

Vitamin D deficiency remains prevalent in our study cohort and is associated with TB progression. Socioeconomic determinants such as unemployment, BMI under 25 kg/m2, and diabetes are the main risk factors for the development of pulmonary TB in our study. A/A polymorphism of TLR8 (rs3764880) and T/T polymorphism (BsmI, rs1544410) of VDR genes may act as biomarkers for pulmonary tuberculosis in the Kazakh population.

Population pharmacokinetic model of rifampicin for personalized tuberculosis pharmacotherapy: Effects of SLCO1B1 polymorphisms on drug exposure

BACKGROUND

Rifampicin (RIF) exhibits high pharmacokinetic (PK) variability among individuals; a low plasma concentration might result in unfavorable treatment outcomes and drug resistance. This study evaluated the contributions of non- and genetic factors to the interindividual variability of RIF exposure, then suggested initial doses for patients with different weight bands.

METHODS

This multicenter prospective cohort study in Korea analyzed demographic and clinical data, the solute carrier organic anion transporter family member 1B1 (SLCO1B1) genotypes, and RIF concentrations. Population PK modeling and simulations were conducted using nonlinear mixed-effect modeling.

RESULTS

In total, 879 tuberculosis (TB) patients were divided into a training dataset (510 patients) and a test dataset (359 patients). A one-compartment model with allometric scaling for effect of body size best described the RIF PKs. The apparent clearance (CL/F) was 16.6% higher among patients in the SLCO1B1 rs4149056 wild-type group than among patients in variant group, significantly decreasing RIF exposure in the wild-type group. The developed model showed better predictive performance compared with previously reported models. We also suggested that patients with body weights of <40 kg, 40-55 kg, 55-70 kg, and >70 kg patients receive RIF doses of 450, 600, 750, and 1050 mg/day, respectively.

CONCLUSIONS

Total body weight and SLCO1B1 rs4149056 genotypes were the most significant covariates that affected RIF CL/F variability in Korean TB patients. We suggest initial doses of RIF based on World Health Organization weight-band classifications. The model may be implemented in treatment monitoring for TB patients.

Determinants of tuberculosis: an example of high tuberculosis burden in the Saharia tribe

Tuberculosis (TB) is a significant public health problem among the Saharia community, an underprivileged tribal group in the west-central part of India. There are several challenges for India's TB control program to curtail TB in the Saharia tribe. Malnutrition, poor health sector facilities, lower socio-economic status, and substance abuse are interconnected and synergistic factors contributing to a high burden of TB in the Saharia tribe. In this review, efforts are made to collate the findings of previous studies discussing the causes of high burden of TB in the Saharia tribe, social gaps for mitigating these preventable risk factors of TB in the Saharia tribe, and the plausible solutions for closing these gaps. The concept of Health in All Policies and intersectoral co-ordination is needed for the reduction of TB in the Saharia tribe and to make India TB-free by the year 2025.

Effects of underweight and overweight on mortality in patients with pulmonary tuberculosis

Background

Poor nutrition increases disease severity and mortality in patients with tuberculosis (TB). There are gaps in our understanding of the effects of being underweight or overweight on TB in relation to sex.

Methods

We generated a nationwide TB registry database and assessed the effects of body mass index (BMI) on mortality in patients with pulmonary TB. The cause of death was further classified as TB-related or non-TB-related deaths. First, logistic regression analysis was performed to assess the association between BMI (a continuous variable) and mortality, and subgroup analyses of the multivariable logistic regression model were performed separately in male and female patients. Second, we categorized BMI into three groups: underweight, normal weight, and overweight, and assessed the impact of being underweight or overweight on mortality with reference to normal weight.

Results

Among 9,721 patients with pulmonary TB, the mean BMI was 21.3 ± 3.4; 1,927 (19.8%) were underweight, and 2,829 (29.1%) were overweight. In multivariable logistic regression analysis, mortality was significantly increased with the decrement of BMI (adjusted odds ratio [aOR] = 0.893, 95% confidence interval [CI] = 0.875-0.911). In subgroup analyses, underweight patients had significantly higher odds of mortality, especially TB-related deaths (aOR = 2.057, 95% CI = 1.546-2.735). The association with mortality and male patients was higher (aOR = 2.078, 95% CI = 1.717-2.514), compared with female patients (aOR = 1.724, 95% CI = 1.332-2.231). Being overweight had a significant protective effect against TB-related death only in females (aOR = 0.500, 95% CI = 0.268-0.934), whereas its effect on non-TB-related death was observed only in males (aOR = 0.739, 95% CI = 0.587-0.930).

Conclusion

Being underweight was linked to high mortality, whereas being overweight had beneficial effects in patients with pulmonary TB.

On-Field Test of Tuberculosis Diagnosis through Exhaled Breath Analysis with a Gas Sensor Array

Tuberculosis (TB) is among the more frequent causes of death in many countries. For pulmonary TB, early diagnosis greatly increases the efficiency of therapies. Although highly sensitive tests based on nucleic acid amplification tests (NAATs) and loop-mediated isothermal amplification (TB-LAMP) are available, smear microscopy is still the most widespread diagnostics method in most low-middle-income countries, and the true positive rate of smear microscopy is lower than 65%. Thus, there is a need to increase the performance of low-cost diagnosis. For many years, the use of sensors to analyze the exhaled volatile organic compounds (VOCs) has been proposed as a promising alternative for the diagnosis of several diseases, including tuberculosis. In this paper, the diagnostic properties of an electronic nose (EN) based on sensor technology previously used to identify tuberculosis have been tested on-field in a Cameroon hospital. The EN analyzed the breath of a cohort of subjects including pulmonary TB patients (46), healthy controls (38), and TB suspects (16). Machine learning analysis of the sensor array data allows for the identification of the pulmonary TB group with respect to healthy controls with 88% accuracy, 90.8% sensitivity, 85.7% specificity, and 0.88 AUC. The model trained with TB and healthy controls maintains its performance when it is applied to symptomatic TB suspects with a negative TB-LAMP. These results encourage the investigation of electronic noses as an effective diagnostic method for future inclusion in clinical practice.

Cell death induced by NLRP3-palmitate axis impairs pulmonary damage tolerance and aggravates immunopathology during obesity-tuberculosis comorbidity

A low-grade and persistent inflammation, which is the hallmark of obesity, requires the participation of NLRP3 and cell death. During Mycobacterium tuberculosis infection, NLRP3 signaling is important for bacterial killing by macrophages in vitro but was shown to be dispensable for host protection in vivo. We hypothesized that during obesity-tuberculosis (TB) comorbidity, NLRP3 signaling might play a detrimental role by inducing excessive inflammation. We employed a model of high-fat-diet-induced obesity, followed by M. tuberculosis infection in C57BL/6 mice. Obese mice presented increased susceptibility to infection and pulmonary immunopathology compared to lean mice. Using treatment with NLRP3 antagonist and Nlrp3^-/- mice, we showed that NLRP3 signaling promoted cell death, with no effect in bacterial loads. The levels of palmitate were higher in the lungs of obese infected mice compared to lean counterparts, and we observed that this lipid increased M. tuberculosis-induced macrophage death in vitro, which was dependent on NLRP3 and caspase-1. At the chronic phase, although lungs of obese Nlrp3^-/- mice showed an indication of granuloma formation compared to obese wild-type mice, there was no difference in the bacterial load. Our findings indicate that NLRP3 may be a potential target for host-directed therapy to reduce initial and severe inflammation-mediated disease and to treat comorbidity-associated TB. © 2022 The Pathological Society of Great Britain and Ireland.

Malnutrition is Associated with an Increased Risk of Death in Hospitalized Patients with Active Pulmonary Tuberculosis: A Propensity Score Matched Retrospective Cohort Study

Background

This study aimed to investigate whether nutrition levels in patients with active pulmonary tuberculosis (TB) affect their risk of all-cause mortality during hospitalization and to further evaluate the predictive ability of Geriatric Nutritional Risk Index (GNRI) and Body Mass Index (BMI) for risk of all-cause mortality.

Methods

Patients from January 1, 2020 to December 31, 2021 were retrieved, and a total of 1847 were included. The primary outcome was all-cause mortality. Propensity score matching (PSM) was performed for risk adjustment, and receiver operating characteristic (ROC) curve analysis was performed to assess the predictive ability of GNRI and BMI for all-cause mortality.

Results

Malnourished TB patients were older, had more congestive heart failure, and had more chronic obstructive pulmonary disease or asthma. Under the nutrition level grouping defined by GNRI, the all-cause mortality in the malnourished group did not appear to reach a statistical difference compared with the nonmalnourished group (P = 0.078). When grouped by level of nutrition as defined by BMI, the all-cause mortality was higher in the malnourished group (P = 0.009), and multivariate logistic regression analysis revealed that malnutrition was an independent risk factor for all-cause mortality. After propensity score matching, the results showed that the all-cause mortality was higher in the malnutrition group, regardless of BMI or GNRI defined nutrition level grouping, compared with the control group (both P < 0.001). The ROC curve analysis revealed that the area under the curve (AUC) was 0.811 ([95% confidence interval (CI) 0.701–0.922], P < 0.001) for GNRI and 0.728 ([95% CI 0.588–0.869], P = 0.001) for BMI.

Conclusion

In the clinical treatment of patients with active TB, more attention should be paid to the management of nutritional risk. GNRI may be a highly effective and easy method for predicting short-term outcomes in patients with active pulmonary TB.

Association between exercise and risk of cardiovascular diseases in patients with non-cystic fibrosis bronchiectasis

BACKGROUND

Although cardiovascular comorbidities negatively impact survival in patients with bronchiectasis, there is limited evidence to recommend exercise in this population. We aimed to evaluate whether exercise habit changes are related to reduced cardiovascular disease risk and explore an optimal exercise amount.

METHODS

This study identified 165,842 patients with newly diagnosed bronchiectasis during 2010-2016 who underwent two health examinations and were followed up until December 2020. The exposure was the change in weekly habits of moderate- or vigorous-intensity physical activity between the two examinations, classified into non-exercisers and exercisers (further classified into new exercisers, exercise dropouts, and exercise maintainers). The amount of exercise was measured using metabolic equivalents of task (MET). The outcome was the incidence of myocardial infarction (MI) or stroke.

RESULTS

During a mean of 6.2 ± 2.1 follow-up years, 4,233 (2.6%) and 3,745 (2.3%) of patients with bronchiectasis had MI or stroke, respectively. Compared to non-exercisers, exercisers had a significantly lower risk of MI or stroke by 9-28% (p < 0.001 for both). Among exercisers, exercise maintainers showed the lowest risk of MI (adjusted hazard ratio [aHR], 0.72; 95% confidence interval [CI], 0.64-0.81) and stroke (aHR, 0.72; 95% CI, 0.64-0.82) compared to non-exercisers. Regarding exercise amount, a significant risk reduction was observed only in patients with bronchiectasis who exercised for ≥ 500 MET-min/wk.

CONCLUSION

Exercise was associated with a reduced risk of cardiovascular diseases in patients with bronchiectasis. In particular, the risk was lowest in exercise maintainers, and cardiovascular risk reduction was significant when exercising more than 500 MET-min/wk.

Anemia Is a Strong Predictor of Wasting, Disease Severity, and Progression, in Clinical Tuberculosis (TB)

A typical trait of chronic tuberculosis (TB) is substantial weight loss that concurs with a drop in blood hemoglobin (Hb) levels, causing anemia. In this observational study, we explored Hb levels in 345 pulmonary TB patients. They were divided into anemic or non-anemic groups which related to clinical symptoms, anthropometric measurements, and immune status. Data was obtained in a randomized controlled trial that we previously conducted using nutritional supplementation of TB patients in Ethiopia. A post hoc analysis demonstrated that anemic patients have a higher composite clinical TB score at baseline than non-anemic patients. Consequently, Hb values were significantly lower in underweight patients with moderate to severe disease and/or cavitary TB compared to normal weight patients with mild disease or non-cavitary TB. Anemia was associated with a low body mass index (BMI), low mid-upper arm circumference (MUAC), lower peripheral CD4 and CD8 T cells counts and IFN-γ levels, and a higher erythrocyte sedimentation rate (ESR). Chronic inflammation and TB disease progression appeared to be driven by elevated systemic levels of pro-inflammatory IL-6 in anemic patients. Multivariable modeling confirmed that a low Hb and a low BMI were key variables related to an unfavorable TB disease status. Although Hb levels increased with successful chemotherapy, anemic TB patients maintained a slower clinical recovery compared to non-anemic patients during the intensive phase treatment (two months). In conclusion, anemia is a strong predictor of wasting, disease severity, inflammation, and slower recovery in patients with pulmonary TB.

Risk Factors of Incident Lung Cancer in Patients with Non-Cystic Fibrosis Bronchiectasis: A Korean Population-Based Study

BACKGROUND

Patients with non-cystic fibrosis bronchiectasis have an increased risk of lung cancer, followed by higher mortality in this population. Because the risk factors of lung cancer have not been well identified, this study aimed to investigate the risk factors of lung cancer in individuals with newly diagnosed bronchiectasis.

METHODS

This cohort study using the Korean National Health Insurance Service database identified 7425 individuals with incident bronchiectasis among those who participated in the health screening exam in 2009. The cohort was followed from baseline to the date of incident: lung cancer, death, or until the end of the study period. We investigated the risk factors of lung cancer in participants with bronchiectasis using the Cox-proportional hazard models.

RESULTS

During median 8.3 years of follow-up duration, 1.9% (138/7425) developed lung cancer. In multivariable analyses, significant factors associated with increased risk of incident lung cancer included: males (adjusted hazard ratio [HR] = 3.54, 95% confidence interval [CI] = 2.17-5.79) than females, the overweight (adjusted HR = 1.55, 95% CI = 1.03-2.35) than the normal weight, current smokers (adjusted HR = 3.10, 95% CI = 2.00-4.79) than never smokers, participants living in the rural area (adjusted HR = 2.54, 95% CI = 1.68-3.85) than those living in the metropolitan area. Among comorbidities, chronic obstructive pulmonary disease was associated with an increased risk of lung cancer (adjusted HR = 1.46, 95% CI = 1.01-2.13) in participants with bronchiectasis. In contrast, mild alcohol consumption was associated with reduced risk of lung cancer (adjusted HR = 0.47, 95% CI = 0.29-0.74) in those with bronchiectasis.

CONCLUSION

This Korean population-based study showed that males, current smoking, overweight, living in rural areas, and comorbid chronic obstructive pulmonary disease are associated with increased risk of lung cancer in individuals with bronchiectasis.

Long-Term Mortality of Tuberculosis Survivors in Korea: A Population-based Longitudinal Study

BACKGROUND

When assessing long-term tuberculosis (TB) mortality, few studies addressed the impact of behavior habits and socioeconomic status. Therefore, we aimed to evaluate long-term TB mortality and risk factors while accounting for potential confounders.

METHODS

This cohort study included TB survivors (n = 82 098) aged ≥20 years between 2010 and 2017, and 1:1 age- and sex-matched controls (n = 82 098). The participants were followed up for death 1 year after study enrollment until December 2018. Long-term mortality was adjusted for behavior habits (smoking, alcohol consumption, or exercise), income level, body mass index (BMI), and comorbidities.

RESULTS

During a median of 3.7 years of follow-up, the incidence rate of mortality was significantly higher in TB survivors than those in the matched controls (18.2 vs. 8.8 per 1000 person-years, P < .001). Even after adjusting for potential confounders, the mortality risk was 1.62-fold (95% confidence interval [CI], 1.54-1.70) higher in TB survivors than those in the matched controls. In addition, the hazard of mortality in TB survivors relative to matched controls significantly increased in participants aged ≥30 years, with the highest risk in those in their 40s. Male sex (adjusted hazard ratio [HR]: 2.31; 95% CI, 2.16-2.47), smoking pack-years (HR: 1.005; 95% CI, 1.004-1.006), heavy alcohol consumption (HR: 1.12; 95% CI, 1.01-1.23), and lowest income (HR: 1.27; 95% CI, 1.18-1.37) were positively associated with increased hazards for mortality, whereas higher BMI (HR: 0.91; 95% CI, .90-.92) and regular exercise (HR: 0.82; 95% CI, .76-.88) reduced the hazards of long-term mortality in TB survivors.

CONCLUSIONS

The long-term mortality risk was significantly higher in TB survivors than those in the matched controls, even after adjusting for potential confounders.