Impact of combination antiretroviral therapy initiation on adherence to antituberculosis treatment

BACKGROUND: Healthcare workers are often reluctant to start combination antiretroviral therapy (ART) in patients receiving tuberculosis (TB) treatment because of the fear of high pill burden, immune reconstitution inflammatory syndrome, and side-effects. OBJECT: To quantify changes in adherence to tuberculosis treatment following ART initiation. DESIGN: A prospective observational cohort study of ART-naïve individuals with baseline CD4 count between 50 cells/mm(3) and 350 cells/mm(3) at start of TB treatment at a primary care clinic in Johannesburg, South Africa. Adherence to TB treatment was measured by pill count, self-report, and electronic Medication Event Monitoring System (eMEMS) before and after initiation of ART. RESULTS: ART tended to negatively affect adherence to TB treatment, with an 8% – 10% decrease in the proportion of patients adherent according to pill count and an 18% – 22% decrease in the proportion of patients adherent according to eMEMS in the first month following ART initiation, independent of the cut-off used to define adherence (90%, 95% or 100%). Reasons for non-adherence were multifactorial, and employment was the only predictor for optimal adherence (adjusted odds ratio 4.11, 95% confidence interval 1.06–16.0). CONCLUSION: Adherence support in the period immediately following ART initiation could optimise treatment outcomes for people living with TB and HIV.