Increase in Single-Tablet Regimen Use and Associated Improvements in Adherence-Related Outcomes in HIV-Infected Women

Introduction: The use of single-tablet antiretroviral therapy (ART) regimens and its implications on adherence among HIV-infected women have not been well described. Methods: Participants were enrolled in the Women's Interagency HIV Study, a longitudinal study of HIV infection in US women. We examined semiannual trends in single-tablet regimen use and ART adherence, defined as self-reported 95% adherence in the past 6 months, during 2006-2013. In a nested cohort study, we assessed the comparative effectiveness of a single-tablet versus a multiple-tablet regimen with respect to adherence, virologic suppression, quality of life, and AIDS-defining events, using propensity score matching to account for demographic, behavioral, and clinical confounders. We also examined these outcomes in a subset of women switching from a multiple-to single-tablet regimen using a case-crossover design. Results: We included 15,523 person-visits, representing 1727 women (53% black, 29% Hispanic, 25% IDU, median age 47). Use of single-tablet regimens among ART users increased from 7% in 2006% to 27% in 2013; adherence increased from 78% to 85% during the same period (both P < 0.001). Single-tablet regimen use was significantly associated with increased adherence (adjusted risk ratio: 1.05; 95% confidence interval: 1.03 to 1.08) and virologic suppression (risk ratio: 1.06; 95% confidence interval: 1.01 to 1.11), while associations with improved quality of life and fewer AIDS-defining events did not achieve statistical significance. Similar findings were observed among the subset of switchers. Conclusions: Single-tablet regimen use was associated with increased adherence and virologic suppression. Despite this, 15% of women prescribed ART were still not optimally adherent; additional interventions are needed to maximize therapeutic benefits.