Tuberculosis Incidence Rate & Risk Factors among HIV-Infected Adults with Access to Antiretroviral Therapy in Tanzania

To determine the incidence rate and risk factors of tuberculosis (TB) among HIV-infected adults accessing antiretroviral therapy (ART) in Tanzania.

A prospective observational study among HIV-infected adults attending 47 HIV clinics in Dar es Salaam.

We estimated TB incidence rates among HIV-infected patients prior to and after ART initiation. We used Cox proportional hazard regressions to determine the predictors of incident TB among HIV-infected adults enrolled in the HIV care and treatment program.

We assessed 67,686 patients for a median follow-up period of 24 (interquartile range: 8–49) months; 7,602 patients were diagnosed with active TB. The TB incidence rate was 7.9 (95% Confidence Interval (CI), 7.6–8.2)/100 person-years prior to ART initiation, and 4.4(95%CI, 4.2–4.4)/100 person-years for patients receiving ART. In multivariate analyses, patients on ART in the first 3 months had a 57% higher risk of TB (Hazard Ratio:1.57, 95%CI:1.47–1.68) compared to those not on ART, but the risk significantly decreased with increasing duration of ART. Risk factors for incident TB included being male, having low body mass index or middle upper arm circumference, lower CD4 cell count, and advanced WHO disease stage. There was seasonal variation for incident TB, with higher risk observed following the rainy seasons (May, June, and November).

In TB endemic regions, HIV-infected patients initiating ART, particularly males and those with poor nutritional status, should be closely monitored for active TB in the months following ART initiation. In addition to increasing the access to ART, interventions should be considered to improve nutritional status among HIV-infected patient.

Below:  Hazard Ratio of incident tuberculosis by calendar months among HIV-infected adults in Dar Salaam, Tanzania. Note: The diamonds show the Hazard Ratios with January as reference (HR=1.0); The vertical Bars show the 95% confidence intervals. (The P value was calculated based likelihood ratio test by running the multivariate Cox proportional hazard model twice, with and without the 11 calendar-month indicators included)

Below:  Hazard Ratio of incident tuberculosis by duration on ART (with zero as reference) among HIV-infected individuals in Dar es Salaam, Tanzania. Note: The horizontal dot line shows where the hazard ratio equal to 1; the solid line shows hazard ratio; the dot-dash lines show the 95% confidence intervals for hazard ratios; negative times represent time before ART initiation, only patients who have started ART during the follow-up were included to create the graph.

Full article at: http://goo.gl/xHtJKb

By: Enju LIU,a Abel MAKUBI,e Paul DRAIN,f Donna SPIEGELMAN,b,c,d David SANDO,g Nan LI,a Guerino CHALAMILLA,gChristopher R. SUDFELD,a Ellen HERTZMARK,b and Wafaie W. FAWZIa,b,d

^bDepartment of Epidemiology, Harvard School of Public Health, Boston, MA, USA

^cDepartment of Biostatistics, Harvard School of Public Health, Boston, MA, USA

^dDepartment of Nutrition, Harvard School of Public Health, Boston, MA, USA

^eSchool of Medicine, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania

^fDivision of Infectious Diseases and Medical Practice Evaluation Center, Massachusetts General Hospital, Harvard Medical School, Boston, USA

^g

aDepartment of Global Health and Population, Harvard School of Public Health, Boston, MA, USA

bDepartment of Epidemiology, Harvard School of Public Health, Boston, MA, USA

cDepartment of Biostatistics, Harvard School of Public Health, Boston, MA, USA

dDepartment of Nutrition, Harvard School of Public Health, Boston, MA, USA

eSchool of Medicine, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania

fDivision of Infectious Diseases and Medical Practice Evaluation Center, Massachusetts General Hospital, Harvard Medical School, Boston, USA

gManagement and Development for Health, Dar es Salaam, Tanzania

aDepartment of Global Health and Population, Harvard School of Public Health, Boston, MA, USA

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