The Role of Pharmacy Refill Measures in Assessing Adherence and Predicting HIV Disease Markers in Youth with Perinatally-Acquired HIV (PHIV).

Antiretroviral (ARV) adherence is critical in monitoring disease response in youth with perinatally-acquired HIV (PHIV). We used pharmacy refill (PR) information for PHIV youth from the PHACS Memory Sub-study to calculate medication availability over 2, 4, and 6 months. PR, a proxy of adherence, was compared with self-reported 7-day adherence in predicting suppressed viral load (SVL < 400 copies/mL) and higher CD4% (≥ 25%). Among 159 PHIV youth, 79% were adherent by 7-day recall, and 62, 55, and 48% by PR over 2, 4, and 6 months, respectively. Agreement between 7-day recall and PR adherence was weak (Kappa = 0.09-0.25). In adjusted logistic regression models, adherence showed associations with SVL for 7-day recall (OR 2.78, 95% CI 1.08, 7.15) and all PR coverage periods (6-month: OR 3.24, 95% CI 1.22, 8.65). Similar associations were observed with higher CD4%. PR measures were predictive of study retention. Findings suggest a possibly independent role of PR adherence measures.