Measuring Adherence to Antiretroviral Treatment: The Role of Pharmacy Records of Drug Withdrawals

This study aimed to evaluate adherence to antiretroviral treatment (ART) among HIV + adults, assess its association with HIV viral load (VL) and identify factors associated to adherence. A survey involving a random sample of adults followed at a HIV/AIDS reference center in São Paulo city, Brazil, from 2007 to 2009 was done. A questionnaire was applied and data were retrieved from the pharmacy and medical records. The study involved 292 subjects: 70.2% men; median age: 43 years; median duration of ART: 8 years. 89.3% self-reported taken all prescribed pills in the last 3 days but only 39.3% picked up ≥95% of the prescribed ART from the pharmacy in the last 12 months. At the multivariate analysis having symptoms prior to ART, taking fewer ART pills, and not missing medical appointments were independently associated to higher adherence. Adherence was strongly associated with undetectable HIV VL. Rates of undetectable HIV VL did not differ from 80 to ≥95% of adherence.