Adherence, drug use, and treatment failure in a methadone-clinic-based program of directly administered antiretroviral therapy

Supervised dosing is a cornerstone of tuberculosis treatment. HIV treatment strategies that use directly administered antiretroviral therapy (DAART) are increasingly being assessed. In a prospective single-arm clinical trial, we enrolled methadone-maintained, HIV-infected participants to receive supervised doses of antiretroviral therapy (ART) on days when they received methadone. Other ART doses were self-administered. In this analysis we examined factors associated with retention to DAART, adherence to supervised doses, and virologic failure. Factors associated with retention to DAART were assessed with the Kaplan-Meier method and Cox proportional hazards models. Factors associated with nonadherence with supervised dosing and with virologic failure were assessed by logistic regression and techniques for longitudinal data analysis. A total of 16,453 supervised doses were administered to 88 participants over a median follow-up of 9.4 months. The median participant adherence with supervised dosing was 83%. Active drug use, determined by urine drug screens, was associated twofold increased risks of both intervention dropout and nonadherence with supervised doses. Adherence with supervised doses was strongly associated with virologic failure. Because DAART was administered only on methadone dosing days, fewer than half of the total ART doses were scheduled to be supervised in most participants. The percent of doses that was scheduled to be supervised was not associated with either adherence or with virologic failure. Given that a relatively small proportion of the total ART doses were supervised in many patients, future studies should assess how DAART affects adherence with nonsupervised doses and retention to ART.