Impact of antiretroviral therapy on tuberculosis incidence among HIV-positive patients in high-income countries

HIV replication and tuberculosis risk among people living with HIV in Europe: A multicohort analysis, 1983-2015

INTRODUCTION

HIV replication leads to a change in lymphocyte phenotypes that impairs immune protection against opportunistic infections. We examined current HIV replication as an independent risk factor for tuberculosis (TB).

METHODS

We included people living with HIV from 25 European cohorts 1983-2015. Individuals <16 years or with previous TB were excluded. Person-time was calculated from enrolment (baseline) to the date of TB diagnosis or last follow-up information. We used adjusted Poisson regression and general additive regression models.

RESULTS

We included 272,548 people with a median follow-up of 5.9 years (interquartile range [IQR] 2.3-10.9). At baseline, the median CD4 cell count was 355 cells/μL (IQR 193-540) and the median HIV-RNA level 22,000 copies/mL (IQR 1,300-103,000). During 1,923,441 person-years of follow-up, 5,956 (2.2%) people developed TB. Overall, TB incidence was 3.1 per 1,000 person-years (95% confidence interval [CI] 3.02-3.18) and was four times higher in patients with HIV-RNA levels of 10,000 compared with levels <400 copies/mL in any CD4 stratum. CD4 and HIV-RNA time-updated analyses showed that the association between HIV-RNA and TB incidence was independent of CD4. The TB incidence rate ratio for people born in TB-endemic countries compared with those born in Europe was 1.8 (95% CI 1.5-2.2).

CONCLUSIONS

Our results indicate that ongoing HIV replication (suboptimal HIV control) is an important risk factor for TB, independent of CD4 count. Those at highest risk of TB are people from TB-endemic countries. Close monitoring and TB preventive therapy for people with suboptimal HIV control is important.

Incidence and predictors of tuberculosis among HIV-infected children after initiation of antiretroviral therapy in Ethiopia: A systematic review and meta-analysis

BACKGROUND

Globally, Tuberculosis (TB) is the main cause of morbidity and mortality among infectious disease. TB and Human Immune Virus (HIV) are the two deadly pandemics which interconnected each other tragically, and jeopardize the lives of children; particularly in Sub-Saharan Africa. Therefore, this review was aimed to determine the aggregated national pooled incidence of tuberculosis among HIV- infected children and its predictors in Ethiopia.

METHODS

An electronic search engine (HINARI, PubMed, Scopus, web of science), Google scholar and free Google databases were searched to find eligible studies. Quality of the studies was checked using the Joanna Briggs Institute (JBI) quality assessment checklists for cohort studies. Heterogeneity between studies was evaluated using Cochrane Q-test and the I2 statistics.

RESULT

This review revealed that the pooled national incidence of tuberculosis among children with HIV after initiation of ART was 3.63% (95% CI: 2.726-4.532) per 100-person-years observations. Being Anemic, poor and fair ART adherence, advanced WHO clinical staging, missing of cotrimoxazole and isoniazid preventing therapy, low CD4 cell count, and undernutrition were significant predictors of tuberculosis incidence.

CONCLUSION

The study result indicated that the incidence of TB among HIV- infected children is still high. Therefore, parents/guardians should strictly follow and adjust nutritional status of their children to boost immunity, prevent undernutrition and opportunistic infections. Cotrimoxazole and isoniazid preventive therapy need to continually provide for HIV- infected children for the sake of enhancing CD4/immune cells, reduce viral load, and prevent from advanced disease stages. Furthermore, clinicians and parents strictly follow ART adherence.

The Prognosis for Delayed Immune Recovery in HIV-Infected Children might be Associated with Pre-cART CD4 + T cell Count Irrespective of Co-Infection with Tuberculosis

Background

Immune reconstitution following the initiation of combination antiretroviral therapy (cART) significantly impacts the prognosis of individuals infected with human immunodeficiency virus (HIV). Our previous studies have indicated that the baseline CD4+ T cells count and percentage before cART initiation are predictors of immune recovery in TB-negative children infected with HIV, with TB co-infection potentially causing a delay in immune recovery. However, it remains unclear whether these predictors consistently impact immune reconstitution during long-term intensive cART treatment in TB-negative/positive children infected with HIV.

Results

We confirmed that the baseline CD4+ T cell count is a significant predictor of immune recovery following long-term intensive cART treatment among children aged 5 to 18 years. Children with lower CD4+ T cell count prior cART initiation did not show substantial immunological recovery during the follow-up period. Interestingly, children who were co-infected with TB and had higher baseline CD4+ T cell count eventually achieved good immunological recovery comparable to the TB-negative HIV-infected children. Hence, the baseline CD4+ T cell count at the onset of treatment serves as a reliable predictor of immunological reconstitution in HIV-infected children with or without TB co-infection. Taken together, this follow-up study validates our previous findings and further establishes that initiating cART early alongside early HIV testing can help prevent the diminished CD4+ T cell count associated with inadequate immunological reconstitution.

Tuberculosis and its associated risk factors among HIV-positive pregnant women in northwest Ethiopia: A retrospective follow-up study

Background

People living with the human immunodeficiency virus have a higher risk of developing active tuberculosis disease. Human immunodeficiency virus infected pregnant women are at a much higher risk of getting active tuberculosis infection, partly due to immune modulation. However, very little is known about the epidemiology of tuberculosis among pregnant women infected with the virus, particularly in resource-limited settings where the burdens of these infections are substantial. Hence, this study aimed to estimate tuberculosis incidence and identify its risk factors among human immunodeficiency virus infected pregnant women in northwest Ethiopia.

Methods

An institutional-based retrospective follow-up study was conducted among pregnant women who were enrolled in option B+ prevention of mother to child transmission service between June 2013 and April 2021 in Pawe district. The Kaplan-Meier survival curve and Weibull regression model were used to estimate survival probability and identify risk factors of tuberculosis, respectively. The best model between the Cox and parametric models was chosen using the Akaike and Bayesian information criteria.

Result

Out of 289 human immunodeficiency virus infected pregnant women included in the final analysis, 29 (10.03 %) developed active tuberculosis. The overall incidence of tuberculosis was 17.4 per 1000 person-months of observation (95 % CI: 12.1, 25.1). Lack of isoniazid preventive therapy (AHR: 6.68, 95 % CI: 2.67, 16.7), new enrollment to care (AHR: 2.62, 95 % CI: 1.14, 6.03), under-nutrition (AHR: 5.09, 95 % CI: 2.02, 12.83), low CD4 count (AHR: 2.61, 95 % CI: 1.01, 6.78), and suboptimal antiretroviral therapy adherence (AHR: 3.17, 95 % CI: 1.46, 6.86) were predictors of tuberculosis among HIV-positive pregnant women.

Conclusion

This study found a high incidence of tuberculosis among human immunodeficiency virus infected pregnant women. Thus, strengthening the provision of tuberculosis preventive therapy, reinforcing adherence support, and controlling under-nutrition should be considered to decrease the risk of tuberculosis.

HIV-associated lung disease

Lung disease encompasses acute, infectious processes and chronic, non-infectious processes such as chronic obstructive pulmonary disease, asthma and lung cancer. People living with HIV are at increased risk of both acute and chronic lung diseases. Although the use of effective antiretroviral therapy has diminished the burden of infectious lung disease, people living with HIV experience growing morbidity and mortality from chronic lung diseases. A key risk factor for HIV-associated lung disease is cigarette smoking, which is more prevalent in people living with HIV than in uninfected people. Other risk factors include older age, history of bacterial pneumonia, Pneumocystis pneumonia, pulmonary tuberculosis and immunosuppression. Mechanistic investigations support roles for aberrant innate and adaptive immunity, local and systemic inflammation, oxidative stress, altered lung and gut microbiota, and environmental exposures such as biomass fuel burning in the development of HIV-associated lung disease. Assessment, prevention and treatment strategies are largely extrapolated from data from HIV-uninfected people. Smoking cessation is essential. Data on the long-term consequences of HIV-associated lung disease are limited. Efforts to continue quantifying the effects of HIV infection on the lung, especially in low-income and middle-income countries, are essential to advance our knowledge and optimize respiratory care in people living with HIV.

The Effect of Long-Term HAART on the Incidence of Tuberculosis Among People Living with HIV in Addis Ababa, Ethiopia: A Matched Nested Case-Control Study

Background

The introduction of antiretroviral therapy (ART) significantly decreases the incidence of tuberculosis (TB) in people living with human immunodeficiency virus (PLWHIV). However, a considerable proportion is still co-infected with TB after ART initiation. Thus, this study aimed to assess the effect of long-term HAART on the incidence of TB among PLWHIV in Addis Ababa, Ethiopia.

Methods

A matched nested case–control study was conducted among PLWHIV who were enrolled in ART clinics in Addis Ababa, Ethiopia from 2013 up to 2018. Cases were HIV-TB co-infected individuals who were taking antiretroviral treatment, while controls were PLWHIV without TB who were taking antiretroviral treatment. The cases and controls are matched exactly in age and sex. Data were entered in Epi Info version 7.1 and analyzed using SPSS version 20. Bi-variable and multivariable conditional logistic regression were employed along with 95% CI. A P-value <0.05 in the multivariable analysis was considered statistically significant.

Results

Fifty-seven cases were compared with 114 controls. Accordingly, previous TB history (X²; 13.790, P < 0.001), baseline functional status (X²; 9.120, P = 0.010), baseline WHO clinical stage (X²; 10.083, P = 0.001), baseline hemoglobin value (X²; 6.985, P = 0.008), baseline body mass index (X²; 3.873, P = 0.049), isoniazid preventive treatment (X²; 8.047, P = 0.005), baseline CD4 value (X²; 12.741, P < 0.001) and length of stay on ART (X²; 53.359, P < 0.001) were associated with developing TB. Length of stay on ART was found to be the statistically significant determinant of TB infection after ART initiation (aOR = 5.925, 95% CI = 2.649–13.250).

Conclusion

Advanced clinical stages at the baseline, previous TB history, and not taking IPT were associated with TB infection. The long-term ART exposure significantly decreases tuberculosis incidence in PLWHIV. Thus, retaining PLWHIV on ART would be important to decrease the incidence of TB in this group of individuals.

Incidence and predictors of tuberculosis among HIV patients after initiation of antiretroviral treatment in Ethiopia: a systematic review and meta-analysis

Background

Tuberculosis is the oldest infectious disease and it is still the leading cause of morbidity and mortality worldwide. Even though several primary studies have been conducted on the incidence of tuberculosis among HIV-infected individuals in Ethiopia, national-level tuberculosis incidence is unknown. Therefore, this study is aimed to assess the TB incidence rate and its predictors among HIV-infected individuals after the initiation of ART in Ethiopia.

Methods

We conducted an extensive search of literature as indicated in the guideline of reporting systematic review and meta-analysis (PRISMA). The databases used were PubMed, Google Scholar, and HINARI literature. We used the Joanna Briggs Institute (JBI) Meta-Analysis of Statistics Assessment and Review Instrument for critical appraisal of studies. The meta-analysis and Meta regressions were conducted using STATA 14 software. Met-analysis and meta-regression were computed to present the pooled incidence rate and predictors of tuberculosis among HIV-infected patients after initiation of ART with a 95% confidence interval.

Results

Among a total of 189 studies, 11 studies were included in this analysis. The estimated pooled incidence rate of TB per 100-person year observation (PYO) among HIV-infected patients after initiation of ART therapy was 4.8(95% CI 3.69–5.83). In subgroup analysis, the estimated pooled incidence of tuberculosis showed a slight difference between adults and children after initiation of ART treatment, which was 4.3 (95% CI 2.96, 5.71) and 5.0 (95% CI 3.51, 6.50), respectively. Significantly pooled estimates of predictors of TB incidence by a meta-analysis were being anemic (2.30, 95% CI 1.75, 3.02); on clinical stages III and IV (2.26, 95% CI 1.70, 3.02); and not on cotrimoxazole preventive therapy (CPT) (2.16, 95% CI 1.23, 3.72). Besides, a meta-regression revealed that CD4 <200 cells/mm³ (2.12, 95% CI 1.17, 3.86) was a positive significant predictor of TB among HIV patients after the initiation of ART.

Conclusions

The current study showed that the pooled incidence of TB among HIV patients was found to be lower than the WHO 2018 national estimate. Being anemic, WHO stages III and IV, not on CPT, CD4<200cells/μl, and being male were significant predictors of tuberculosis. Therefore, the existing strategies to decrease TB should be strengthening.

Study protocol registration

CRD42020155573.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41182-021-00306-2.

Role of CD4/CD8 ratio on the incidence of tuberculosis in HIV-infected patients on antiretroviral therapy followed up for more than a decade

Background

The role of CD4/CD8 ratio on the incidence of tuberculosis (TB) in patients on antiretroviral therapy (ART) is unknown. Thus, we sought to determine whether the CD4/CD8 ratio was associated with development of TB in a cohort of HIV infected individuals on ART followed up for more than a decade in the setting of sub-Saharan Africa (SSA).

Methods

The cohort comprised adult patients who started ART between 2001 and 2007 and followed for up to 15 years. Clinical data were collected in retrospective manner. Patients with an AIDS defining illness or a CD4 count <200 cell/μL were started with a combination of ART. The participants have clinic visits every 6 months and/or as needed. Poisson regression models were used to identify factors associated with development of incident TB. Kaplan-Meier curves were used to estimate the probability of incident TB while on ART.

Results

A total of 347 patients with a median duration of follow-up on ART of 11.5 (IQR: 10.0–12.5) years were included. Incident TB developed in 47 patients during the 3259 person-years of follow-up, the majority (76.6%) occurred within five year of ART initiation. On univariate analysis, poor ART adherence (RR:2.57, 95% CI: 1.28–5.17), time-updated CD4 cell count of lower than 200 (RR: 4.86, 95%CI 2.33–10.15), or CD4 cell count between 200 and 500 (RR: 4.68, 95% CI: 2.17–10.09), time-updated CD8 cell count lower than 500 (RR: 2.83 95% CI 1.31–6.10), or CD8 cell count over 1000 (RR: 2.23, 95% CI: 1.12–4.45), time-updated CD4/CD8 ratio of less than 0.30 (RR: 6.00, 95% CI: 2.96–12.14), lack of normalization of CD4 T-cell count (RR: 6.13, 95% CI: 2.20–17.07), and virological failure (RR: 2.35 (95% CI: 1.17–4.71) were all associated with increased risk of incident TB. In multivariate analysis, however, time-updated CD4/CD8 ratio of less than 0.30 (adjusted RR: 4.08, 95% CI: 1.31–12.68) was the only factor associated with increased risk of developing incident TB (p = 0.015). Similar results were obtained in a sensitivity analysis by including only those virally suppressed patients (n = 233, 69% of all patients). In this group, CD4/CD8 ratio of less than 0.30 was associated with development of incident TB (adjusted RR: 4.02, 95% CI: 1.14–14.19, p = 0.031). Overall, the incidence rate of TB in patients with an updated CD4/CD8 ratio of less than 0.30 was more than 5-fold higher when compared with those with a ratio more than 0.45.

Conclusion

Low CD4/CD8 ratio is independently associated with an increased risk of incident TB despite viral suppression. CD4/CD8 ratio may serve as a biomarker for identifying patients at risk of TB in patients on ART in the setting of SSA.

Incidence and predictors of extrapulmonary tuberculosis among people living with Human Immunodeficiency Virus in Addis Ababa, Ethiopia: A retrospective cohort study

BACKGROUND

Extrapulmonary tuberculosis is an emerging public health problem among HIV positives compared to the general population. This study aimed to assess the incidence and predictors of extrapulmonary tuberculosis among people living with HIV in selected health facilities in Addis Ababa, Ethiopia, from 01 January 2013 up to 31 December 2018.

METHODS

A retrospective cohort study design was employed based on data collected from 566 HIV positive individuals. Data were entered using EpiInfo version 7.1 and analyzed by SPSS version 20. The incidence rate was determined per 100 person-years. Kaplan-Meier estimates used to estimate survivor and the hazard function, whereas log-rank tests used to compare survival curves and hazard across different categories. Cox proportional hazard model was used to identify the predictors and 95%CI of the hazard ratio were computed. P-value<0.05 in the multivariable analysis was considered statistically significant.

RESULTS

Five hundred sixty-six HIV positive individuals were followed for 2140.08 person-years. Among them, 72 developed extrapulmonary tuberculosis that gives an incidence rate of 3.36/100 person-years (95%CI = 2.68-4.22). The most frequent forms of extrapulmonary tuberculosis were; lymph node tuberculosis (56%, 41) followed equally by pleural tuberculosis (15%, 11) and disseminated tuberculosis (15%, 11). The majority (70.83%) of the cases occurred within the first year of follow-up. In multivariable Cox regression analysis, baseline WHO stage III/IV (AHR = 2.720, 95%CI = 1.575-4.697), baseline CD4 count<50cells/μl (AHR = 4.073, 95%CI = 2.064-8.040), baseline CD4 count 50-200 cells/μl (AHR = 2.360, 95%CI = 1.314-4.239) and baseline Hgb<10 mg/dl (AHR = 1.979, 95%CI = 1.091-3.591) were the independent risk factors. While isoniazid prophylaxis (AHR = 0.232, 95%CI = 0.095-0.565) and taking antiretroviral drugs (AHR = 0.134, 95%CI = 0.075-0.238) had a protective benefit.

CONCLUSION

Extrapulmonary tuberculosis co-infection was common among HIV positive individuals, and mostly occurred in those with advanced immune suppression. The risk decreases in those taking antiretroviral therapy and took isoniazid preventive treatment. Screening of HIV positives for extrapulmonary tuberculosis throughout their follow-up would be important.

Incidence and determinants of tuberculosis among HIV-positive individuals in Addis Ababa, Ethiopia: A retrospective cohort study

OBJECTIVE

To assess the incidence and determinants of tuberculosis (TB) among HIV-positive individuals in selected health facilities of Addis Ababa, Ethiopia, during the period January 2013 to December 2018.

METHODS

Data were collected from the records of 566 HIV-positive individuals. A retrospective cohort study design was employed. Data were entered into Epi Info 7 and analyzed using IBM SPSS Statistics version 20. TB incidence density was determined per 100 person-years. Time-to-event distributions were estimated using Kaplan-Meier estimates. Survival curves and hazards across different categories were compared using log-rank tests. Determinants were identified using the Cox proportional hazards model. The hazard ratio (HR) and 95% confidence interval (CI) were computed. A p-value <0.05 in the multivariate analysis was considered statistically significant.

RESULTS

A total of 566 HIV-positive individuals were followed for 2140.08 person-years, giving a TB incidence density rate of 6.82/100 person-years (146, 25.8%). The highest incidence was observed within the first year of follow-up. Independent determinants were large family size (adjusted HR (AHR) 1.783, 95% CI 1.113-2.855), lower baseline CD4 (AHR 2.568, 95% CI 1.602-4.116), and baseline body mass index <18.5 kg/m² (AHR 1.907, 95% CI 1.530-2.690). Being enrolled in antiretroviral treatment (AHR 0.066, 95% CI 0.045-0.98) and taking isoniazid prophylaxis treatment (AHR 0.202, 95% CI 0.108-0.380) had a protective effect.

CONCLUSIONS

TB is still a major cause of morbidity among HIV-positive individuals. Early HIV diagnosis, enrollment on antiretroviral treatment, and isoniazid prophylaxis treatment should be considered to decrease the TB risk.

Incidence of tuberculosis among HIV infected individuals on long term antiretroviral therapy in private healthcare sector in Pune, Western India

Background

Despite rapid scale up of antiretroviral therapy (ART), Tuberculosis (TB) remains the commonest opportunistic infection and cause of death among HIV infected individuals in resource limited settings like India. Incidence of TB in individuals on ART in private healthcare sector in India is infrequently studied.

Methods

This retrospective cohort study conducted between 1st March 2009 and 1st March 2017 aimed to evaluate rate of incident TB in individuals initiated on ART at 3 private sector ART clinics in Pune, India. Individuals more than 12 years of age with ART duration of atleast 6 months were included. Patients were classified as having prevalent TB if they had a TB episode within the year prior to ART initiation or if they developed TB within 6 months of starting ART. Individuals who were diagnosed with TB after 6 months of starting ART were classified as incident TB cases. A recurrent episode of TB after treatment completion or cure of prevalent TB was also regarded as incident TB. Patients were classified as definitive TB if Mycobacterium tuberculosis was grown in culture from a biological sample or a positive rapid molecular test. Patients were classified as probable TB if there was radiologic evidence of TB in absence of confirmatory culture or PCR.

Results

1904 patients with a median duration of follow up on ART of 57 (IQR = 32.0, 84.0) months were included. Of these, 182 developed incident TB (22% definitive TB, 38% recurrent cases). TB incidence at 6–12 months, 13–24 months, 25–60 months and > 60 months of ART was 24.32, 5.46, 2.54 and 0.75 cases per 100 person years respectively. Current time updated CD4 count < 500 cells/mm³ (p < 0.0001), virologic failure on ART (adjusted Hazard Ratio (aHR): 3.05 (95% CI: 2.094, 4.454), p < 0.0001) and receipt of ART without IPT (aHR: 8.24 (95% CI, 3.358, 20.204), p < 0.0001) were associated with higher risk of incident TB.

Conclusion

Starting ART early in treatment naïve individuals, prompt detection of virologic failure on ART and providing IPT along with ART will be useful in reducing incident TB. Efforts from private sector are crucial in achieving Sustainable Development Goals set by Government of India and attaining the vision of a TB free India.

2018 Belgian guidelines for the screening for latent tuberculosis in HIV-infected patients

Objectives: To review the current knowledge on screening for latent tuberculosis infection (LTBI) in HIV-infected adults and provide specific guidelines for Belgium. Focus is given to who to test, which testing method to use, timing of screening and choice of LTBI treatment. Methods: Expert review by the members of the Belgian LTBI group, in consultancy with the ARC College. Results: Target population, timing of screening, testing method, active TB exclusion, treatment of LTBI and guideline implementation are all reviewed. Conclusions: The principal changes include a selective approach to screen for LTBI (screening only of the HIV-infected patients at highest risk of active TB) as well as the timing of screening (testing for LTBI performed only after immune-restauration by antiretroviral therapy).

Prospects for a vaccine to prevent HIV-related tuberculosis

PURPOSE OF REVIEW

To outline the need for a new tuberculosis (TB) vaccine; challenges for induction of vaccine-mediated protection in HIV-infected persons; and recent advances in clinical development.

RECENT FINDINGS

HIV has a detrimental effect on T-cell function, polarization and differentiation of Mycobacterium tuberculosis (Mtb)-specific T cells, Mtb antigen presentation by dendritic cells, and leads to B-cell and antibody-response deficiencies. Previous observations of protection against TB disease in HIV-infected persons by Mycobacterium obuense suggest that an effective vaccine against HIV-related TB is feasible. Studies of inactivated mycobacterial, viral-vectored and protein subunit vaccines reported lower immune responses in HIV-infected relative to HIV-uninfected individuals, which were only partially restored with antiretroviral therapy. Bacille Calmette Guerin (BCG) revaccination of HIV-uninfected adolescents recently showed moderate efficacy against sustained Mtb infection, but live mycobacterial vaccines have an unfavorable risk profile for HIV-infected persons. Ongoing trials of inactivated mycobacterial and protein-subunit vaccines in HIV-uninfected, Mtb-infected adults may be more relevant for protection of HIV-infected populations in TB endemic countries.

SUMMARY

New TB vaccine candidates have potential to protect against HIV-related TB, through vaccination prior to or after HIV acquisition, but this potential may only be realized after efficacy is demonstrated in HIV-uninfected populations, with or without Mtb infection.

Age-related comorbidities and mortality in people living with HIV in rural Tanzania

OBJECTIVE

Causes of morbidity and mortality of people living with HIV are changing with access to antiretroviral therapy and increased life expectancy. Age-related data on comorbidities and their impact on mortality in sub-Saharan Africa are scarce.

DESIGN

This prospective analysis evaluated comorbidities, assessed by means of International Classification of Diseases and Related Health problems 10th revision codes and clinical variables, derived from data collected from the Kilombero & Ulanga antiretroviral cohort of people living with HIV in rural Tanzania.

METHODS

We calculated prevalences and incidences of comorbidities in patients enrolled from 2013 to 2017 and evaluated their association with a combined endpoint of death and loss to follow-up (LTFU) in various age groups (15-29, 30-49 and ≥50 years) using Cox regression analysis.

RESULTS

Of 1622 patients [65% females, median age 38 years (interquartile range 31-46)], 11% were at least 50 years. During a median follow-up of 22.1 months (interquartile range 10.6-37.3), 48 (2.9%) patients died and 306 (18.9%) were LTFU. Anaemia was the most prevalent comorbidity (66.3%) irrespective of age and was associated with increased mortality/LTFU [hazard ratios 2.02 (95% confidence interval (CI) 1.57-2.60); P < 0.001]. In patients aged at least 50 years, arterial hypertension was highly prevalent (43.8%), but not associated with mortality/LTFU [hazard ratios 1.04 (95% CI 0.56-1.93), P = 0.9]. Undernutrition ranged from 25.5% in the youngest to 29.1% in the oldest age group and contributed to mortality/LTFU [hazard ratios 2.24 (95% CI 1.65-3.04); P < 0.001]. Prevalence of tuberculosis was 21.4% with hazard ratios of 2.54 (95% CI 1.72-3.75, P < 0.001) for mortality/LTFU.

CONCLUSION

We show that anaemia, arterial hypertension and undernutrition are the most relevant comorbidities with different age-associated frequencies and impact on death/LTFU in this population.

Association of highly active antiretroviral treatment with incident tuberculosis in people living with HIV/AIDS

PURPOSE

To determine the short-term and long-term effects of highly active antiretroviral therapy (HAART) on incident tuberculosis (TB) in people living with HIV/AIDS (PLWHA).

METHODS

From 2000 to 2012, we identified adult PLWHA from Taiwan Centers for Disease Control HIV Surveillance System. All PLWHA were followed up until December 31, 2012, and observed for TB occurrence. Time-dependent Cox proportional hazards models were used to determine the short-term and long-term effects of HAART on incident TB.

RESULTS

Of 20,072 PLWHA, 628 (3.13%) had incident TB, corresponding to an incident rate of 701/100,000 person-years. After adjusting for potential confounders, PLWHA receiving HAART were more likely to develop TB than those not receiving the drugs (adjusted hazard ratio [AHR] 1.56; 95% confidence interval [CI] 1.18-2.05). While the short-term and long-term effects of HAART on incident TB were considered, HAART was a risk factor for TB development within the first 90 days (AHR 6.06; 95% CI 4.58-8.01) and between 90 and 180 days of treatment (AHR 1.80; 95% CI 1.11-2.94) but was a protective factor after 180 days of HAART use (AHR 0.51; 95% CI 0.39-0.66).

CONCLUSIONS

HAART is a risk factor for the development of TB in the short term but a protective factor in the long term.

Use of antiretrovirals in HIV-infected children in a tuberculosis prevention trial: IMPAACT P1041

SETTING

International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) P1041, a tuberculosis (TB) prevention trial conducted among children enrolled from 2004 to 2008 during South Africa's roll-out of combination antiretroviral therapy (ART).

OBJECTIVE

To estimate TB incidence and mortality and the effect of ART.

DESIGN

Children were pre-screened to exclude TB disease and exposure, actively screened 3-monthly for TB exposure and symptoms, and provided post-exposure isoniazid prophylaxis therapy (IPT). TB diagnoses were definite, probable, or possible, and mortality all-cause. Testing was at the 5% significance level.

RESULTS

In 539 children (aged 3-4 months) followed up for a median of 74 weeks (interquartile range [IQR] 48-116), incidence/100 person-years (py) was 10.67 (95%CI 8.47-13.26) for any TB and 2.89 (95%CI 1.85-4.31) for definite/probable TB. Any TB incidence was respectively 9.39, 13.59, and 9.83/100 py before, <180 days after, and 180 days after ART initiation. Adjusted analysis showed a non-significant increase in any TB (HR 1.32, 95%CI 0.71-2.52, P = 0.38) and a significant reduction in mortality (HR 0.39, 95%CI 0.17-0.82, P = 0.017) following ART initiation.

CONCLUSIONS

ART reduced mortality but not TB incidence in human immunodeficiency virus (HIV) infected children in IMPAACT P1041, possibly attributable to active screening for TB exposure and symptoms with post-exposure IPT. Research into this as a strategy for TB prevention in high HIV-TB burden settings may be warranted.

Using Observational Data to Calibrate Simulation Models

BACKGROUND

Individual-level simulation models are valuable tools for comparing the impact of clinical or public health interventions on population health and cost outcomes over time. However, a key challenge is ensuring that outcome estimates correctly reflect real-world impacts. Calibration to targets obtained from randomized trials may be insufficient if trials do not exist for populations, time periods, or interventions of interest. Observational data can provide a wider range of calibration targets but requires methods to adjust for treatment-confounder feedback. We propose the use of the parametric g-formula to estimate calibration targets and present a case-study to demonstrate its application.

METHODS

We used the parametric g-formula applied to data from the HIV-CAUSAL Collaboration to estimate calibration targets for 7-y risks of AIDS and/or death (AIDS/death), as defined by the Center for Disease Control and Prevention under 3 treatment initiation strategies. We compared these targets to projections from the Cost-effectiveness of Preventing AIDS Complications (CEPAC) model for treatment-naïve individuals presenting to care in the following year ranges: 1996 to 1999, 2000 to 2002, or 2003 onwards.

RESULTS

The parametric g-formula estimated a decreased risk of AIDS/death over time and with earlier treatment. The uncalibrated CEPAC model successfully reproduced targets obtained via the g-formula for baseline 1996 to 1999, but over-estimated calibration targets in contemporary populations and failed to reproduce time trends in AIDS/death risk. Calibration to g-formula targets improved CEPAC model fit for contemporary populations.

CONCLUSION

Individual-level simulation models are developed based on best available information about disease processes in one or more populations of interest, but these processes can change over time or between populations. The parametric g-formula provides a method for using observational data to obtain valid calibration targets and enables updating of simulation model inputs when randomized trials are not available.

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.

Is systematic screening and treatment for latent tuberculosis infection in HIV patients useful in a low endemic setting?

OBJECTIVES

A decreasing incidence of tuberculosis (TB) among HIV patients has been documented in high-income settings and screening for tuberculosis is not systematically performed in many clinics (such as ours). Our objectives are to evaluate whether a same decline of incidence was seen in our Belgian tertiary center and to evaluate whether systematic screening and prophylaxis of tuberculosis should remain part of routine practice.

METHODS

Between 2005 and 2012, the annual incidence of tuberculosis among adult HIV patients was measured. The impact of demographic characteristics and CD₄ nadir on the incidence of active TB was evaluated.

RESULTS

Among the 1167 patients who entered the cohort, 42 developed active TB with a significant decrease of annual incidence from 28/1000 patient-years in 2005 to 3/1000 patient-years in 2012. Among the 42 cases, 83% were of sub-Saharan origin. Median CD4 cell count upon HIV diagnosis was significantly lower in TB cases and 60% had a nadir CD4 below 200/μl. Thirty-six percent of incident TB occurred within 14 days after HIV diagnosis.

CONCLUSION

A significant decline of TB incidence in HIV patients was observed. Incident TB occurred mainly in African patients, with low CD4 upon HIV diagnosis. A significant proportion of TB cases were discovered early in follow-up which probably reflects TB already present upon HIV diagnosis. In a low endemic setting, exclusion of active TB upon HIV diagnosis remains a priority and screening for LTBI should focus on HIV patients from high risk groups such as migrants from endemic regions, especially in patients with low CD4 nadir.

Timing of Antiretroviral Treatment, Immunovirologic Status, and TB Risk: Implications for Testing and Treatment

BACKGROUND

Tuberculosis (TB) risk and mortality increase in the 6 months after highly active antiretroviral therapy (HAART) initiation. This short-term risk may be a consequence of HAART initiation and immune reconstitution. Alternatively, it may be due to confounding by low CD4 counts and high HIV viral loads (VLs). We assessed the TB risk before and after HAART initiation while appropriately controlling for time-updated laboratory values and HAART exposure.

METHODS

We conducted an observational cohort study among persons enrolled in the North American AIDS Cohort Collaboration on Research and Design from 1998 through 2011. A marginal structural model was constructed to estimate the association of HAART initiation and TB risk. Inverse probability weights for the probability of HAART initiation were incorporated.

RESULTS

Among 26,342 patients, 94 cases of TB were diagnosed during 147,557 person-years (p-y) of follow-up. The unadjusted TB rates were 93/100,000 p-y [95% confidence interval (CI): 63 to 132] before HAART initiation, 203/100,000 p-y (95% CI: 126 to 311) ≤6 months after HAART initiation, and 40/100,000 p-y (95% CI: 29 to 55) >6 months on HAART. After controlling for time-updated laboratory values, the adjusted odds of TB ≤6 months after HAART initiation and >6 months was 0.65 (95% CI: 0.28 to 1.51) and 0.29 (95% CI: 0.16 to 0.53), respectively.

CONCLUSIONS

TB risk in the first 6 months after HAART initiation is not higher than that before HAART initiation after adjusting for CD4 count and VLs. These findings suggest that short-term TB risk may be related to low CD4 counts and high VLs near HAART initiation and support early HAART initiation to decrease TB risk.

Tuberculosis and HIV coinfection in Europe: looking at one reality from two angles

Objective:

To better understand the epidemiology of tuberculosis (TB)/HIV coinfection in the European Union (EU) and European Economic Area (EEA) for planning of prevention and control measures.

Design:

Analysis of surveillance data.

Methods:

We performed an analysis of the 2014 TB and AIDS data to assess the burden of TB/HIV coinfection and we applied multivariable logistic regression to evaluate predictors for coinfection.

Results:

Twenty-one of 31 EU/EEA countries reported HIV testing results for 64.6% of the 32 892 notified TB cases. Of those, 1051 (4.9%) were reported as HIV-positive. Males [adjusted odds ratio (aOR) 1.25; 95% confidence interval (CI) 1.07–1.46] and those in age group 25–44 years were more frequently coinfected. TB cases originating from the WHO African region had the highest proportion of coinfection (aOR 3.28 versus origin in EU/EEA; 95% CI 2.35–4.57). TB treatment was completed successfully by 57.9% of HIV-positive TB cases and 83.5% of HIV-negative cases. In 2014, 3863 cases of AIDS were reported by 29 EU/EEA countries; 691 (17.9%) of these cases presented with TB as an AIDS-defining illness. Persons who had acquired HIV through injecting drug use had higher odds of TB as an AIDS-defining illness (aOR 1.78 versus heterosexual route of transmission; 95% CI 1.37–2.32).

Conclusion:

TB/HIV coinfection is a substantial problem in the EU/EEA. The occurrence of TB in HIV-positive cases and the low TB treatment success rate suggest that international guidelines for prevention and treatment of TB in HIV-infected adults need to be better implemented.

Declining tuberculosis case notification rates with the scale-up of antiretroviral therapy in Zimbabwe

Setting: Zimbabwe has a human immunodeficiency virus (HIV) driven tuberculosis (TB) epidemic, with antiretroviral therapy (ART) scaled up in the public sector since 2004. Objective: To determine whether national ART scale-up was associated with annual national TB case notification rates (CNR), stratified by disease type and category, between 2000 and 2013. Design: This was a retrospective study using aggregate data from global reports. Results: The number of people living with HIV and retained on ART from 2004 to 2013 increased from 8400 to 665 299, with ART coverage increasing from <0.5% to 48%. TB CNRs, all types and categories, increased from 2000 to 2003, and declined thereafter from 2004 to 2013. The decreases in annual TB notifications between the highest rates (before 2004) and lowest rates (2013) were all forms of TB (56%), new TB (60%), previously treated TB (53%), new smear-positive pulmonary TB (PTB) (40%), new smear-negative/smear-unknown PTB (58%) and extra-pulmonary TB (58%). Conclusion: Significant declines in TB CNRs were observed during ART scale-up, especially for smear-negative PTB and extra-pulmonary TB. These encouraging national trends support the continued scale-up of ART for people living with HIV as a way of tackling the twin epidemics of HIV/acquired immune-deficiency syndrome and TB in Zimbabwe.

Antiretroviral Treatment Efficacy and Safety in Older HIV-Infected Adults

Highly active antiretroviral therapy (ART) and its widespread availability have revolutionized the landscape of HIV care and patient outcomes, transforming infection with HIV into a manageable chronic condition rather than a life-limiting disease. This transformation has created an older patient demographic. The effect that older age has on the outcomes of ART is not completely understood. Limited data are available in older individuals due to underrepresentation in clinical trials. To better understand this relationship, we conducted a literature search to assess the impact of older age on the outcomes of ART in the older HIV-infected population, including immunologic and virologic outcomes, mortality, disease progression, toxicity of ART, and pharmacokinetic considerations. In addition, package inserts of antiretroviral (ARV) medications were reviewed for efficacy, safety, and pharmacokinetic information pertaining to the older population. Most studies in older adults (50 yrs or older) demonstrated slower and blunted CD4 immune recovery but better virologic suppression in response to ART. Higher rates of mortality and faster disease progression have been observed in adults 50 years and older, particularly during the first year after ART initiation. HIV-infected patients aged 50 years and older appear to be at greater risk for certain ART-associated toxicities including nephrotoxicity, decline in bone mineral density and bone fracture, symptomatic peripheral neuropathy, and cardiovascular disease including myocardial infarction. The available literature suggests that clinicians should consider avoiding agents such as tenofovir disoproxil fumarate (TDF) in older patients with risk factors for renal impairment and/or osteoporosis. If TDF is used in patients aged 50 years or older, more frequent monitoring should be considered. Older age was a significant predictor for higher atazanavir exposure and higher lopinavir trough concentration at 24 weeks. The clinical implications of these findings are unknown. It is imperative that future development of novel ARV drug therapies includes a greater proportion of older subjects in clinical trials.

Estimating tuberculosis cases and their economic costs averted in the United States over the past two decades

BACKGROUND

Following a concerted public health response to the resurgence of tuberculosis (TB) in the United States in the late 1980s, annual TB incidence decreased substantially. However, no estimates exist of the number and cost savings of TB cases averted.

METHODS

TB cases averted in the United States during 1995-2014 were estimated: Scenario 1 used a static 1992 case rate; Scenario 2 applied the 1992 rate to foreign-born cases, and a pre-resurgence 5.1% annual decline to US-born cases; and a statistical model assessed human immunodeficiency virus and TB program indices. We applied the cost of illness to estimate the societal benefits (costs averted) in 2014 dollars.

RESULTS

During 1992-2014, 368 184 incident TB cases were reported, and cases decreased by two thirds during that period. In the scenarios and statistical model, TB cases averted during 1995-2014 ranged from approximately 145 000 to 319 000. The societal benefits of averted TB cases ranged from US$3.1 to US$6.7 billion, excluding deaths, and from US$6.7 to US$14.5 billion, including deaths.

CONCLUSIONS

Coordinated efforts in TB control and prevention in the United States yielded a remarkable number of TB cases averted and societal economic benefits. We illustrate the value of concerted action and targeted public health funding.

Hierarchy Low CD4+/CD8+ T-Cell Counts and IFN-γ Responses in HIV-1+ Individuals Correlate with Active TB and/or M.tb Co-Infection

OBJECTIVE

Detailed studies of correlation between HIV-M.tb co-infection and hierarchy declines of CD8+/CD4+ T-cell counts and IFN-γ responses have not been done. We conducted case-control studies to address this issue.

METHODS

164 HIV-1-infected individuals comprised of HIV-1+ATB, HIV-1+LTB and HIV-1+TB- groups were evaluated. Immune phenotyping and complete blood count (CBC) were employed to measure CD4+ and CD8+ T-cell counts; T.SPOT.TB and intracellular cytokine staining (ICS) were utilized to detect ESAT6, CFP10 or PPD-specific IFN-γ responses.

RESULTS

There were significant differences in median CD4+ T-cell counts between HIV-1+ATB (164/μL), HIV-1+LTB (447/μL) and HIV-1+TB- (329/μL) groups. Hierarchy low CD4+ T-cell counts (<200/μL, 200-500/μL, >500/μL) were correlated significantly with active TB but not M.tb co-infection. Interestingly, hierarchy low CD8+ T-cell counts were not only associated significantly with active TB but also with M.tb co-infection (P<0.001). Immunologically, HIV-1+ATB group showed significantly lower numbers of ESAT-6-/CFP-10-specific IFN-γ+ T cells than HIV-1+LTB group. Consistently, PPD-specific IFN-γ+CD4+/CD8+ T effector cells in HIV-1+ATB group were significantly lower than those in HIV-1+LTB group (P<0.001).

CONCLUSIONS

Hierarchy low CD8+ T-cell counts and effector function in HIV-1-infected individuals are correlated with both M.tb co-infection and active TB. Hierarchy low CD4+ T-cell counts and Th1 effector function in HIV-1+ individuals are associated with increased frequencies of active TB, but not M.tb co-infection.

Paradoxical reactions and immune reconstitution inflammatory syndrome in tuberculosis

The coalescence of the HIV-1 and tuberculosis (TB) epidemics in Sub-Saharan Africa has had a significant and negative impact on global health. The availability of effective antimicrobial treatment for both HIV-1 (in the form of highly active antiretroviral therapy (HAART)) and TB (with antimycobacterial agents) has the potential to mitigate the associated morbidity and mortality. However, the use of both HAART and antimycobacterial therapy is associated with the development of inflammatory paradoxical syndromes after commencement of therapy. These include paradoxical reactions (PR) and immune reconstitution inflammatory syndromes (IRIS), conditions that complicate mycobacterial disease in HIV seronegative and seropositive individuals. Here, we discuss case definitions for PR and IRIS, and explore how advances in identifying the risk factors and immunopathogenesis of these conditions informs our understanding of their shared underlying pathogenesis. We propose that both PR and IRIS are characterized by the triggering of exaggerated inflammation in a setting of immunocompromise and antigen loading, via the reversal of immunosuppression by HAART and/or antimycobacterials. Further understanding of the molecular basis of this pathogenesis may pave the way for effective immunotherapies for the treatment of PR and IRIS.

Implementation and Operational Research: Cost-Effectiveness of Antiretroviral Therapy and Isoniazid Prophylaxis to Reduce Tuberculosis and Death in People Living With HIV in Botswana

OBJECTIVE

In Botswana, a 36-month course of isoniazid treatment of latent tuberculosis (TB) infection [isoniazid preventive therapy (IPT)] was superior to 6-month IPT in reducing TB and death in persons living with HIV (PLHIV), having positive tuberculin skin tests (TSTs) but not in those with negative TST. We examined the cost-effectiveness of IPT in Botswana, where antiretroviral therapy (ART) is widely available.

DESIGN

Using a decision-analytic model, we determined the incremental cost-effectiveness of strategies for reducing TB and death in 10,000 PLHIV over 36 months.

METHODS

IPT for 6 months and provision of ART if CD4 lymphocyte count <250 cells per microliter (2011 Botswana policy) was compared with 6 alternative strategies that varied the use of IPT, TST, and ART for CD4 count thresholds, including CD4 <350 and <500 cells per microliter.

RESULTS

Botswana policy, 2011 was dominated by most other strategies. IPT of 36 months for TST-positive PLHIV with ART for CD4 <250 cells per microliter resulted in 120 fewer TB cases for an additional cost of $1612 per case averted and resulted in 80 fewer deaths for an additional $2418 per death averted compared with provision of 6-month IPT to TST-positive PLHIV who received ART for CD4 <250 cells per microliter, the next most effective strategy. Alternative strategies offered lower incremental effectiveness at higher cost. These findings remained consistent in sensitivity analyses.

CONCLUSIONS

A strategy of treating PLHIV who have positive TST with 36-month IPT is more cost effective for reducing both TB and death compared with providing IPT without a TST, providing only 6-month IPT, or expanding ART eligibility without IPT.

Tenofovir DF/emtricitabine and efavirenz combination therapy for HIV infection in patients treated for tuberculosis: the ANRS 129 BKVIR trial

BACKGROUND

HIV-infected patients with TB need simplified, effective and well-tolerated antiretroviral regimens.

METHODS

The French ANRS 129 BKVIR open trial evaluated the once-daily tenofovir DF/emtricitabine and efavirenz combination, started within 12 weeks after TB treatment initiation, in antiretroviral-naive HIV-1-infected patients. Success was defined as an HIV-1 RNA <50 copies/mL and TB cure at 48 weeks.

RESULTS

TB was confirmed microbiologically (90%) or histologically (10%) in 69 patients (71% male; median age 43 years; 54% born in Africa). The median time between TB treatment initiation and antiretroviral therapy was 8 weeks (range 1-22 weeks). At baseline, median HIV-1 RNA was 5.4 log10 copies/mL and median CD4 cell count 74 cells/mm(3). In the ITT analysis, combined success at week 48 was achieved in 57/69 patients (83%, 95% CI 74-92). Twelve patients did not achieve virological success, and TB was not cured in one of them. Among the 47 patients who fully adhered to the strategy, the success rate was 96% (95% CI 90-100) and was not affected by low rifampicin and isoniazid serum concentrations. Forty-nine serious adverse events were reported in 31 patients (45%), and 11 led to antiretroviral drug interruption. All adverse events resolved. The immune reconstitution inflammatory syndrome occurred in 23 patients (33%, 95% CI 22-44), and was associated with a low baseline BMI (P = 0.03) and a low haemoglobin level (P = 0.02).

CONCLUSION

These results support the use of tenofovir DF/emtricitabine and efavirenz combination therapy for HIV infection in patients with TB.

Effect of antiretroviral treatment on the risk of tuberculosis during South Africa's programme expansion

OBJECTIVE

The objective of this study is to estimate the effectiveness of antiretroviral treatment (ART) in preventing tuberculosis (TB) in HIV-infected people during the first 6 years of ART programme expansion.

DESIGN

A cohort study comparing TB risk without ART and after ART initiation.

SETTING

Public sector HIV programme of the Free State province, South Africa.

PARTICIPANTS

Seventy-four thousand and seventy-four HIV-infected people enrolled from 2004 until 2010, of whom 43 898 received ART and 30 176 did not.

INTERVENTION

Combination ART.

MAIN OUTCOME MEASURES

Time to first TB diagnosis, adjusted for CD4 cell count, weight, age, sex, previous TB, district and year, with ART, CD4 cell count and weight as time-varying covariates and with death as a competing risk.

RESULTS

Three thousand eight hundred and fifty-eight first TB episodes occurred during 78 202 person-years at risk with ART and 5669 episodes occurred during 62 801 person-years without ART [incidence rates 4.9 and 9.0 per 100 person-years, crude incidence rate ratio 0.55 (95% confidence interval 0.52-0.57)]. The adjusted subhazard ratio (SHR) of time to first TB episode after starting ART, compared with follow-up without ART, was 0.67 (0.64-0.70). Within CD4 cell count subgroups (<50, 50-199, 100-199, 200-349 and >350 cells/μl), the respective SHRs were 0.64 (0.57-0.71), 0.63 (0.57-0.70), 0.66 (0.61-0.72), 0.67 (0.62-0.72), 0.72 (0.63-0.83) and 0.97 (0.60-1.59). Adjusted SHRs for ART decreased with each year of enrolment, from 0.90 (0.77-1.04) in 2004 to 0.54 (0.43-0.67) in 2010.

CONCLUSION

ART was effective in preventing TB in HIV-infected patients with CD4 cell counts below 350 cells/μl, but less so than previously estimated. Effectiveness increased each year.

Incidence of tuberculosis and immunological profile of TB/HIV co-infected patients in Nigeria

BACKGROUND:

We obtained estimates of the incidence of tuberculosis (TB) among patients receiving HIV Treatment. We also modeled the relationship between incident TB and change in CD4 count over the follow-up period.

METHODS:

We analyzed the incidence of TB over 10 years from initiation of HIV treatment among 345 HIV treatment-naïve persons, who were enrolled in a cohort in Kano, Nigeria. We used Generalized Estimating Equation [GEE] to identify determinants of TB incidence and model the relationship between the occurrences of TB with change in CD4 count over the follow-up period. We created Kaplan-Meier curves stratified by anti-retroviral therapy (ART) treatment failure status to examine the effect of first line ART treatment failure on occurrence of TB.

RESULT:

During the 10-year period, 47(13.62%) had TB [incidence was 7.43 per (1,000) person year)]. It is associated with decreasing age (OR = 0.98), female gender (OR = 0.83), being on first line ART other than AZT (OR = 0.87), poor adherence (OR = 1.25), change in ART regimen (OR = 2.3) and ART treatment failure (OR = 1.51). Odds of TB occurrence was also associated with CD4 increment at 10 years (OR = 0.99). Those with TB/HIV co-infection tend to have statistically significant shorter time to failing first line ART regimen compared to those with HIV infection alone.

CONCLUSION:

There was high incidence of TB in the studied HIV cohort with a deleterious effect on the outcome of ART treatment. There is need for early TB screening and re-screening among all HIV patients.

Redefining the HIV epidemic in Nigeria: from national to state level

BACKGROUND

Governments are increasingly recognizing the need to focus limited HIV resources on specific geographic areas and specific populations to have a greater impact. Nigeria, with the second largest HIV epidemic in the world, is an important example of where more localized programming has the potential to improve the efficiency of the HIV response.

METHODS

Using Spectrum software we modelled the Nigerian HIV epidemic using two methods: First, we created national HIV estimates using trends in urban and rural areas. Second, we created national HIV estimates using trends from each of the 37 states in Nigeria and aggregated these results. In both instances we used HIV surveillance data from antenatal clinics and household surveys and aggregated the trends to determine the national epidemic.

RESULTS

The state models showed divergent trends in the 37 states. Comparing the national results calculated from the two methods resulted in different conclusions. In the aggregated state files, adult HIV incidence in Nigeria was stable between 2005 and 2013 (change of -6%), whereas the urban and rural file suggested incidence was decreasing over the same time (change of -50%). This difference was also reflected in the HIV prevalence trends, although the two methods showed similar trends in AIDS-related mortality. The two models had similar adult HIV prevalence in 2013: 3.0% (2.0-4.5%) in the aggregated state files versus 3.2% (3.0-3.5%) in the urban/rural file.

CONCLUSION

The state-level estimates provide insight into the variations of the HIV epidemic in each state and provide useful information for programme managers. However, the reliability of the results is highly dependent on the amount and quality of data available from each sub-national area.

[Bibliometric analysis of the Spanish scientific production in Infectious Diseases and Microbiology]

INTRODUCTION

The bibliometric analysis of production and impact of documents by knowledge area is a quantitative and qualitative indicator of research activity in this field. The aim of this article is to determine the contribution of Spanish research institutions in Infectious Diseases and Microbiology in recent years.

MATERIAL AND METHODS

Documents published in the journals included in the categories "Infectious Diseases" and "Microbiology" of the Web of Science (Science Citation Index Expanded) of the ISI Web of Knowledge from the year 2000-2013 were analysed.

RESULTS

In Infectious Diseases, Spain ranked fourth worldwide, and contributed 5.7% of the 233,771 documents published in this specialty. In Microbiology, Spain was in sixth place with a production rate of 5.8% of the 149,269 documents of this category. The Spanish production increased over the study period, both in Infectious Diseases and Microbiology, from 325 and 619 documents in 2000 to 756 and 1245 documents in 2013, with a growth rate of 131% and 45.8%, respectively. The journal with the largest number of documents published was Enfermedades Infecciosas y Microbiología Clínica, with 8.6% and 8.2% of papers published in the categories of Infectious Diseases and Microbiology, respectively, and was the result of international collaborations, especially with institutions in the United States. The "index h" was 116 and 139 in Infectious Diseases and Microbiology, placing Spain in fifth place in both categories within countries of the European Union.

CONCLUSIONS

In recent years, Spanish research in Infectious Diseases and Microbiology has reached a good level of production and international visibility, reaching a global leadership position.

Does antiretroviral therapy reduce HIV-associated tuberculosis incidence to background rates? A national observational cohort study from England, Wales, and Northern Ireland

BACKGROUND

Whether the incidence of tuberculosis in HIV-positive people receiving long-term antiretroviral therapy (ART) remains above background population rates is unclear. We compared tuberculosis incidence in people receiving ART with background rates in England, Wales, and Northern Ireland.

METHODS

We analysed a national cohort of HIV-positive individuals linked to the national tuberculosis register. Tuberculosis incidence in the HIV-positive cohort (2007-11) was stratified by ethnic origin and time on ART and compared with background rates (2009). Ethnic groups were defined as follows: the black African group included all individuals of black African origin, including those born in the UK and overseas; the white ethnic group included all white individuals born in the UK and overseas; the south Asian group included those of Indian, Pakistani, and Bangladeshi origin, born in the UK and overseas; and the other ethnic group included all other ethnic origins, including black Afro-Caribbeans.

FINDINGS

The HIV-positive cohort comprised 79 919 individuals, in whom there were 1550 incident cases in 231 664 person-years of observation (incidence 6·7 cases per 1000 person-years). Incidence of tuberculosis in the HIV-positive cohort was 13·6 per 1000 person-years in black Africans and 1·7 per 1000 person-years in white individuals. Incidence of tuberculosis during long-term ART (≥5 years) in black Africans with HIV was 2·4 per 1000 person-years, similar to background rates of 1·9 per 1000 person-years in this group (rate ratio 1·2, 95% CI 0·96-1·6; p=0·083); but in white individuals with HIV on long-term ART the incidence of 0·5 per 1000 person-years was higher than the background rate of 0·04 per 1000 person-years (rate ratio 14·5, 9·4-21·3; p<0·0001). The increased incidence relative to background in white HIV-positive individuals persisted when analysis was restricted to person-time accrued on ART with CD4 counts of at least 500 cells per μL and when white HIV-positive individuals born abroad were excluded.

INTERPRETATION

Tuberculosis incidence is unacceptably high irrespective of HIV status in black Africans. In white individuals with HIV, tuberculosis incidence is significantly higher than background rates in white people despite long-term ART. Expanded testing and treatment for latent tuberculosis infection to all HIV-infected adults, irrespective of ART status and CD4 cell count, might be warranted.

FUNDING

Public Health England.

A Bundle of Services Increased Ascertainment of Tuberculosis among HIV-Infected Individuals Enrolled in a HIV Cohort in Rural Sub-Saharan Africa

OBJECTIVES

To report on trends of tuberculosis ascertainment among HIV patients in a rural HIV cohort in Tanzania, and assessing the impact of a bundle of services implemented in December 2012, consisting of three components: (i) integration of HIV and tuberculosis services; (ii) GeneXpert for tuberculosis diagnosis; and (iii) electronic data collection.

DESIGN

Retrospective cohort study of patients enrolled in the Kilombero Ulanga Antiretroviral Cohort (KIULARCO), Tanzania.).

METHODS

HIV patients without prior history of tuberculosis enrolled in the KIULARCO cohort between 2005 and 2013 were included.Cox proportional hazard models were used to estimate rates and predictors of tuberculosis ascertainment.

RESULTS

Of 7114 HIV positive patients enrolled, 5123 (72%) had no history of tuberculosis. Of these, 66% were female, median age was 38 years, median baseline CD4+ cell count was 243 cells/µl, and 43% had WHO clinical stage 3 or 4. During follow-up, 421 incident tuberculosis cases were notified with an estimated incidence of 3.6 per 100 person-years (p-y) [95% confidence interval (CI) 3.26-3.97]. The incidence rate varied over time and increased significantly from 2.96 to 43.98 cases per 100 p-y after the introduction of the bundle of services in December 2012. Four independent predictors of tuberculosis ascertainment were identified:poor clinical condition at baseline (Hazard Ratio (HR) 3.89, 95% CI 2.87-5.28), WHO clinical stage 3 or 4 (HR 2.48, 95% CI 1.88-3.26), being antiretroviralnaïve (HR 2.97, 95% CI 2.25-3.94), and registration in 2013 (HR 6.07, 95% CI 4.39-8.38).

CONCLUSION

The integration of tuberculosis and HIV services together with comprehensive electronic data collection and use of GeneXpert increased dramatically the ascertainment of tuberculosis in this rural African HIV cohort.

Doubly robust estimation and causal inference in longitudinal studies with dropout and truncation by death

Motivated by aging research, we propose an estimator of the effect of a time-varying exposure on an outcome in longitudinal studies with dropout and truncation by death. We use an inverse-probability weighted (IPW) estimator to derive a doubly robust augmented inverse-probability weighted (AIPW) estimator. IPW estimation involves weights for the exposure mechanism, dropout, and mortality; AIPW estimation additionally involves estimating data-generating models via regression. We demonstrate that the estimators identify a causal contrast that is a function of principal strata effects under a set of assumptions. Simulations show that AIPW estimation is unbiased when weights or outcome regressions are correct, and that AIPW estimation is more efficient than IPW estimation when all models are correct. We apply the method to a study of vitamin D and gait speed among older adults.

Attitudes about tuberculosis prevention in the elimination phase: a survey among physicians in Germany

Background

Targeted and stringent measures of tuberculosis prevention are necessary to achieve the goal of tuberculosis elimination in countries of low tuberculosis incidence.

Methods

We ascertained the knowledge about tuberculosis risk factors and stringency of tuberculosis prevention measures by a standardized questionnaire among physicians in Germany involved in the care of individuals from classical risk groups for tuberculosis.

Results

510 physicians responded to the online survey. Among 16 risk factors immunosuppressive therapy, HIV-infection and treatment with TNF-antagonist were thought to be the most important risk factors for the development of tuberculosis in Germany. Exposure to a patient with tuberculosis ranked on the 10^th position. In the event of a positive tuberculin-skin-test or interferon-γ release assay only 50%, 40%, 36% and 25% of physicians found that preventive chemotherapy was indicated for individuals undergoing tumor necrosis factor-antagonist therapy, close contacts of tuberculosis patients, HIV-infected individuals and migrants, respectively.

Conclusions

A remarkably low proportion of individuals with latent infection with Mycobacterium tuberculosis belonging to classical risk groups for tuberculosis are considered candidates for preventive chemotherapy in Germany. Better knowledge about the risk for tuberculosis in different groups and more stringent and targeted preventive interventions will probably be necessary to achieve tuberculosis elimination in Germany.

High rates of tuberculosis in patients accessing HAART in rural South Africa

BACKGROUND

The challenge of early tuberculosis (TB) infection among rural patients accessing highly active antiretroviral therapy (HAART) in a resource-limited setting with high HIV and TB burden has not been fully quantified.

METHODS

This is a retrospective study nested within a prospective study of 969 patients consecutively initiated onto HAART at the CAPRISA AIDS Treatment programme in rural KwaZulu-Natal between January 2007 and December 2010. Patients were screened for clinical symptoms consistent with TB using a standardized checklist, and routine clinical investigations that included sputum microscopy and chest x-ray diagnosis.

RESULTS

Of 969 HIV-infected patients initiated on HAART, 173 [17.9%; 95% confidence interval (CI): 15.5 to 20.4] had active TB at HAART initiation. TB incidence rates were 3-fold higher in the first 3 months (early incident TB) after HAART initiation [11.5/100 person-years (py); 95% CI: 7.1 to 17.5] compared with 4-24 months (late incident TB) post-HAART initiation (3.2/100 py; 95% CI: 2.2 to 4.5; incidence rate ratio: 3.6; 95% CI: 2.0 to 6.4; P < 0.001). Immune status of patients at HAART initiation did not impact TB incidence rates in patients with CD4 counts of <50 (5.3/100) and >200 (4.9/100 py; P = 0.81) cells per cubic millimeter. CD4 count gains achieved 12 months post-HAART initiation were significantly different in patients with early incident TB versus late incident TB; P = 0.03.

CONCLUSIONS

Rural HIV treatment programmes in TB-endemic settings experience high rates of TB irrespective of immunologic status of patients at HAART initiation, or duration on HAART.

Tuberculosis among people living with HIV/AIDS in the German ClinSurv HIV Cohort: long-term incidence and risk factors

Background

Tuberculosis (TB) still presents a leading cause of morbidity and mortality among people living with HIV/AIDS (PLWHA), including those on antiretroviral therapy. In this study, we aimed to determine the long-term incidence density rate (IDR) of TB and risk factors among PLWHA in relation to combination antiretroviral therapy (cART)-status.

Methods

Data of PLWHA enrolled from 2001 through 2011 in the German ClinSurv HIV Cohort were investigated using survival analysis and Cox regression.

Results

TB was diagnosed in 233/11,693 PLWHA either at enrollment (N = 62) or during follow-up (N = 171). The TB IDR during follow-up was 0.37 cases per 100 person-years (PY) overall [95% CI, 0.32-0.43], and was higher among patients who never started cART and among patients originating from Sub-Saharan Africa (1.23 and 1.20 per 100PY, respectively). In two multivariable analyses, both patients (I) who never started cART and (II) those on cART shared the same risk factors for TB, namely: originating from Sub-Saharan Africa compared to Germany (I, hazard ratio (HR); [95% CI]) 4.05; [1.87-8.78] and II, HR 5.15 [2.76-9.60], CD4+ cell count <200 cells/μl (I, HR 8.22 [4.36-15.51] and II, HR 1.90 [1.14-3.15]) and viral load >5 log₁₀ copies/ml (I, HR 2.51 [1.33-4.75] and II, HR 1.77 [1.11-2.82]). Gender, age or HIV-transmission risk group were not independently associated with TB.

Conclusion

In the German ClinSurv HIV cohort, patients originating from Sub-Saharan Africa, with low CD4+ cell count or high viral load at enrollment were at increased risk of TB even after cART initiation. As patients might be latently infected with Mycobacterium tuberculosis complex, early screening for latent TB infection and implementing isoniazid preventive therapy in line with available recommendations is crucial.

Incidence and associated factors of pulmonary tuberculosis in HIV-infected children after highly active antiretroviral therapy (HAART) in China: a retrospective study

China is a country with high tuberculosis (TB) incidence but relatively low HIV prevalence. However, due to difficulties in diagnosis and reporting, true burden of HIV-associated TB in children is unknown. The objective of this study was to describe the incidence of pulmonary TB (PTB) after antiretroviral therapy (ART) and to study risk factors. A retrospective study was performed based on routinely collected data from China national pediatric free antiretroviral treatment database. A total of 3365 children under 15 years on ART from July 2005 to October 2012 were included. Multivariable logistic regression was used to detect associated factors. Two thousand nine hundred and ninety (89%) children got infected from HIV-positive mother, with median age of 6.7 (4.1, 10.0) years at highly active antiretroviral therapy (HAART) initiation in this program. Seventy-seven (2.3%) children were diagnosed with PTB after ART during 7.3 years cohort observation. Median time of occurrence was 212 (30-514) days. Overall incidence was 0.83 (0.65-1.01)/100 person-years (py), with the peak of 3.6/100 py in the first 3 months after antiretroviral treatment. WHO stage IV at baseline showed 2 (95% CI 1.0-6.8) times more risk for developing TB. Late clinical stage at ART initiation was shown to relate with TB incidence. PTB coinfection leads to higher mortality. Early diagnosis and treatment of HIV are highly required to reduce HIV-associated morbidity and mortality due to TB.

Co-trimoxazole prophylaxis is associated with reduced risk of incident tuberculosis in participants in the Swiss HIV Cohort Study

Co-trimoxazole reduces mortality in HIV-infected adults with tuberculosis (TB), and in vitro data suggest potential antimycobacterial activity of co-trimoxazole. We aimed to evaluate whether prophylaxis with co-trimoxazole is associated with a decreased risk of incident TB in Swiss HIV Cohort Study (SHCS) participants. We determined the incidence of TB per 1,000 person-years from January 1992 to December 2012. Rates were analyzed separately in participants with current or no previous antiretroviral treatment (ART) using Poisson regression adjusted for CD4 cell count, sex, region of origin, injection drug use, and age. A total of 13,431 cohort participants contributed 107,549 person-years of follow-up: 182 patients had incident TB-132 (73%) before and 50 (27%) after ART initiation. The multivariable incidence rate ratios for cumulative co-trimoxazole exposure per year for persons with no previous ART and current ART were 0.70 (95% confidence interval [CI], 0.55 to 0.89) and 0.87 (95% CI, 0.74 to 1.0), respectively. Co-trimoxazole may prevent the development of TB among HIV-positive persons, especially among those with no previous ART.

Application of marginal structural models in pharmacoepidemiologic studies: a systematic review

PURPOSE

We systematically reviewed pharmacoepidemiologic studies published in 2012 that used inverse probability weighted (IPW) estimation of marginal structural models (MSM) to estimate the effect from a time-varying treatment.

METHODS

Potential studies were retrieved through a citation search within Web of Science and a keyword search within PubMed. Eligibility of retrieved studies was independently assessed by at least two reviewers. One reviewer performed data extraction, and a senior epidemiologist confirmed the extracted information for all eligible studies.

RESULTS

Twenty pharmacoepidemiologic studies were eligible for data extraction. The majority of reviewed studies did not report whether the positivity assumption was checked. Six studies performed intention-to-treat analyses, but none of them reported adherence levels after treatment initiation. Eight studies chose an as-treated analytic strategy, but only one of them reported modeling the multiphase of treatment use. Almost all studies performing as-treated analyses chose the most recent treatment status as the functional form of exposure in the outcome model. Nearly half of the studies reported that the IPW estimate was substantially different from the estimate derived from a standard regression model.

CONCLUSIONS

The use of IPW method to control for time-varying confounding is increasing in medical literature. However, reporting of the application of the technique is variable and suboptimal. It may be prudent to develop best practices in reporting complex methods in epidemiologic research.

Incidence and mortality of tuberculosis disease in Spain between 1997 and 2010: impact of human immunodeficiency virus (HIV) status

OBJECTIVE

To estimate incidence and mortality of TB disease in Spain, as well as TB recurrence and its mortality, and to analyse its trend from 1997 to 2010 in human immunodeficiency virus (HIV)-infected patients (HIV(+) group), compared to HIV-uninfected subjects (HIV(-) group).

METHODS

We performed a retrospective study using data from Minimum Basic Data Set. The outcome variables were new TB diagnosis, TB recurrences, and mortality; which were analysed through three calendar periods related to widespread use of combination antiretroviral therapy (cART): a) From 1997 to 1999 for early-period cART; b) from 2000 to 2003 for mid-period cART; and c) from 2004 to 2008 for late-period cART.

RESULTS

We studied 86,093 HIV-uninfected patients and 17,031 HIV infected patients. TB diagnosis in HIV(-) group (events per 100,000 patients-yr) decreased from 20.16 (1997-1999) to 16.31 (2000-2003; p < 0.001), and later to 13.48 (2004-2010; p < 0.001); and among HIV(+) group (events per 1000 patients-yr) it decreased from 19.23 (1997-1999) to 10.93 (2000-2003; p < 0.001), and later to 6.35 (2004-2010; p < 0.001). For the mortality, HIV(-) group (events per 1,000,000 patients-yr) decreased from 11.5 (1997-1999) to 9.8 (2000-2003; p < 0.001), and later to 7.2 (2004-2010; p < 0.001); and HIV(+) group (events per 10,000 patients-yr) decreased from 20.69 (1997-1999) to 13.20 (2000-2003; p < 0.001), and later to 6.83 (2004-2010; p < 0.001). During the whole period, the diagnostic rate and mortality of TB remained 100-fold higher in HIV(+) group than HIV(-) group (p < 0.001). Moreover, HIV (+) group had higher percentage of patients with TB recurrence than HIV(-) group (p < 0.001).

CONCLUSION

TB diagnosis and mortality decreased in Spain between 1997 and 2010, in both HIV infected patients and people without HIV infection; but these rates remained higher in HIV infected patients.

Drug resistance profiles of Mycobacterium tuberculosis complex and factors associated with drug resistance in the Northwest and Southwest Regions of Cameroon

BACKGROUND

Anti-tuberculosis drug resistance continues to be a major obstacle to tuberculosis (TB) control programmes with HIV being a major risk factor in developing TB. We investigated anti-TB drug resistance profiles and the impact of socioeconomic as well as behavioural factors on the prevalence of TB and drug resistance in two regions of Cameroon with such data paucity.

METHODS

This was a hospital-based study in which 1706 participants, comprising 1133 females and 573 males consecutively enrolled from selected TB and HIV treatment centres of the Northwest and Southwest regions. Demographic, clinical and self-reported risk behaviours and socioeconomic data were obtained with the consent of participants using questionnaires. Culture and drug resistance testing were performed according to standard procedures.

RESULTS

The prevalence of resistance to at least one anti-TB drug was 27.7% and multi-drug resistance was 5.9%. Smoking, concurrent alcohol consumption and smoking, being on antiretroviral therapy for ≤ 12 months and previous household contact with TB patient were independently associated with tuberculosis prevalence, while only previous tuberculosis infection was associated with drug resistance in a univariate analysis.

CONCLUSION

The study showed a high prevalence of drug resistance TB in the study population with only previous TB infection associated with drug resistance in a univariate analysis. It also provides evidence in our context, of the role of alcohol and smoking in increasing the risk of developing TB, which is more likely in people living with HIV/AIDS. Therefore, it is important for public health authorities to integrate and intensify alcohol/smoking abstention interventions in TB and HIV control programs in Cameroon.

Predicting the long-term impact of antiretroviral therapy scale-up on population incidence of tuberculosis

Objective

To investigate the impact of antiretroviral therapy (ART) on long-term population-level tuberculosis disease (TB) incidence in sub-Saharan Africa.

Methods

We used a mathematical model to consider the effect of different assumptions about life expectancy and TB risk during long-term ART under alternative scenarios for trends in population HIV incidence and ART coverage.

Results

All the scenarios we explored predicted that the widespread introduction of ART would initially reduce population-level TB incidence. However, many modelled scenarios projected a rebound in population-level TB incidence after around 20 years. This rebound was predicted to exceed the TB incidence present before ART scale-up if decreases in HIV incidence during the same period were not sufficiently rapid or if the protective effect of ART on TB was not sustained. Nevertheless, most scenarios predicted a reduction in the cumulative TB incidence when accompanied by a relative decline in HIV incidence of more than 10% each year.

Conclusions

Despite short-term benefits of ART scale-up on population TB incidence in sub-Saharan Africa, longer-term projections raise the possibility of a rebound in TB incidence. This highlights the importance of sustaining good adherence and immunologic response to ART and, crucially, the need for effective HIV preventive interventions, including early widespread implementation of ART.

Antiretroviral therapy for prevention of HIV and tuberculosis: a promising intervention but not a panacea

The demonstration of the efficacy of antiretroviral therapy (ART) for HIV prevention in heterosexual HIV serodiscordant couples has resulted in the call for widespread implementation of "Treatment as Prevention" (TasP) to confront the challenge of continued transmission of HIV. In addition, evidence of the possible effect of use of ART on decreasing the incidence of tuberculosis (TB) in persons living with HIV has also contributed further enthusiasm. Mathematical modeling studies evaluating the potential impact of TasP on the trajectory of the HIV and TB epidemics have inspired discussions about a possible future without AIDS. We present the evidence regarding the effect of ART on the incidence of HIV and TB, benefits and risks associated with embracing TasP, and the need for multicomponent prevention strategies and for further research to generate empiric data on the effect of TasP on HIV and TB at a population level.

HIV and co-infections

Despite significant reductions in morbidity and mortality secondary to availability of effective combination anti-retroviral therapy (cART), human immunodeficiency virus (HIV) infection still accounts for 1.5 million deaths annually. The majority of deaths occur in sub-Saharan Africa where rates of opportunistic co-infections are disproportionately high. In this review, we discuss the immunopathogenesis of five common infections that cause significant morbidity in HIV-infected patients globally. These include co-infection with Mycobacterium tuberculosis, Cryptococcus neoformans, hepatitis B virus, hepatitis C virus, and Plasmodium falciparum. Specifically, we review the natural history of each co-infection in the setting of HIV, the specific immune defects induced by HIV, the effects of cART on the immune response to the co-infection, the pathogenesis of immune restoration disease (IRD) associated with each infection, and advances in the areas of prevention of each co-infection via vaccination. Finally, we discuss the opportunities and gaps in knowledge for future research.