Duration of Viral Suppression and Risk of Rebound Viremia with First-Line Antiretroviral Therapy in Rural Uganda.

Abstract

Little is known about associations between viral suppression, adherence, and duration of prior viral suppression in sub-Saharan Africa. Study participants were from the UARTO study in Mbarara, Uganda. We fit regression models to characterize relationships between average adherence, treatment interruptions, and rebound viremia (>400 copies/mL) following a previously undetectable result. Our goal was to understand the impact of prior viral suppression on these relationships. 396 participants contributed 2864 quarterly visits. Restricted to periods with average adherence <50%, each 10% increase in adherence reduced the odds of rebound viremia by 74% [adjusted odds ratio (AOR)=0.26, P=0.002] and 29% (AOR=0.71, P=0.057) during the first 12months of suppression and beyond 12months respectively, interaction term P=0.018. Among periods with adherence ≥50%, the risk of rebound viremia decreased with increasing adherence during the first 12months of viral suppression (AOR=0.73 for each 10% increase, P=0.001), but not thereafter (AOR=1.09, P=0.67), interaction term P=0.027. In contrast, 72-h interruptions, were associated with increased rebound viremia during the first 12months (AOR=1.30, P=0.009) and after (AOR=1.39, P=0.005), interaction term P=0.69. Completing 12months of viral suppression decreases the impact of average adherence, but not prolonged treatment interruptions, on risk of rebound viremia.