Newer HIV regimens are typically taken once daily but vary in the number of pills required. Whether the number of pills in a once-daily HIV regimen affects clinical outcomes is unknown. We retrospectively compared adherence, retention in care, and virologic outcomes between patients starting a once daily single-tablet regimen (STR) to patients starting a once-daily multi-tablet regimen (MTR) in a publicly funded clinic in the United States. Outcomes were measured in the year after starting ART and included retention in care, virologic suppression, and medication possession ratio of at least 80%. Data from patients initiating therapy from 1 January 2008 to 31 December 2011 were analyzed with both unadjusted and propensity-score adjusted regression. Overall, 622 patients started with an STR (100% efavirenz-based) and 406 with an MTR (65% atazanavir-based and 35% darunavir-based) regimen. Retention in care was achieved in 80.7% of STR patients vs. 72.7% of MTR patients (unadjusted OR 1.57, 95% CI 1.17-2.11; adjusted OR 1.49, 95% CI 1.10-2.02). Virologic suppression occurred among 84.4% of STR patients vs. 77.6% of MTR patients (unadjusted OR 1.56; 95% CI 1.14-2.15; adjusted OR 1.41; 95% CI 1.02-1.96). There was no difference in the proportion of patients achieving at least 80% adherence, as measured by medication possession ratio (33.0% of STR patients and 30.1% of MTR patients; unadjusted OR 1.14; 95% CI 0.87-1.50; adjusted OR 1.04, CI 0.79-1.38). While it is difficult to eliminate confounding in this observational study, retention in care and virologic outcomes were better in patients prescribed STRs.
Keywords: Adherence; pill burden; retention in care.