Provider assessment of adherence to HIV antiretroviral therapy

Background: Adherence assessment is an essential component of monitoring HI V antiretroviral therapy. Prior studies suggest that medical providers freq uently estimate individual patient adherence inaccurately. Objective: We compared provider estimates of nonadherence to antiretroviral therapy with unannounced pill counts and structured patient interviews to determine the accuracy of adherence information obtained by providers and p atients. Design, Setting, and participants: Comparison of three adherence measures i n homeless or marginally housed persons receiving HIV antiretroviral therap y (n = 45) and their providers (n = 35). Measurements: Provider estimate of percentage of pills taken: three success ive patient structured reports of number of doses missed in the last 3 days : and three successive unannounced pill counts. Results: 13% (95% confidence interval [CI], 4%-22%) of patients were not fo llowing their regimen as directed. Provider-adherence estimate explained on ly 26% (95% CI, 6%-47%) of the variation in pill count adherence, whereas p atient report explained 72% (95% CI, 52%-96%). The sensitivity and specific ity of provider estimates of nonadherence. defined as <80% of pills taken b y pill count. were 40% and 85%, respectively. The sensitivity and specifici ty of patient interview were 72% and 95%. respectively. Conclusions: Provider estimate of adherence was inaccurate whereas structur ed patient report was more closely related to pill count. Structured assess ment over several short intervals may improve accuracy of adherence assessm ent in clinical practice.