Background: Antiretroviral therapy (ART) markedly reduces the risk of HIV-1 transmission in serodiscordant partnerships. We previously found that younger age and higher CD4 counts were associated with delayed initiation of ART by HIV-1-infected partners in serodiscordant partnerships. Among those initiating ART, we sought to explore whether those same factors were associated with failure to achieve viral suppression.
Methods: In a prospective study of HIV-1-infected persons who had a known heterosexual HIV-1-uninfected partner in Kenya and Uganda [Partners Pre-Exposure Prophylaxis (PrEP) Study], we used Cox proportional hazards regression to evaluate correlates of viral nonsuppression (HIV-1 RNA >80 copies/ml).
Results: Of 1,035 HIV-1-infected participants initiating ART, 867 (84%) achieved viral suppression: 77% by 6 months and 86% by 12 months. Younger age [adjusted hazard ratio (aHR) 1.05 for every 5 years younger; p = .006], lower pretreatment CD4 count (aHR 1.26; p = .009 for ≤250 compared with >250 cells/μl), and higher pretreatment HIV-1 RNA quantity (aHR 1.21 per log10; p < .001) independently predicted failure to achieve viral suppression. Following initial viral suppression, 8.8% (76/867) experienced virologic rebound (HIV-1 RNA >200 copies/ml): 6.3% and 11.5% by 6 and 12 months after initial suppression, respectively. Age was the only factor associated with increased risk of virologic rebound (aHR 1.33 for every 5 years younger; p = .005).
Conclusions: For HIV-1-infected persons in serodiscordant couples, younger age was associated with delayed ART initiation, failure to achieve viral suppression, and increased risk of virologic rebound. Motivating ART initiation and early adherence is a key to achieving and sustaining viral suppression.