Impact of enhanced services on virologic outcomes in a directly administered antiretroviral therapy trial for HIV-infected drug users

BACKGROUND: Directly administered antiretroviral therapy (DAART) is a promising intervention for improving HIV outcomes among active drug users, but the elements associated with successful DAART programs remain largely unknown. This study aimed to assess the impact of colocated medical, case management, and referral to substance abuse services (DAART-Plus) among the subjects receiving DAART as part of a larger randomized controlled trial comparing DAART with self-administered therapy. METHODS: The health services utilization of 72 subjects receiving DAART was analyzed for its impact on changes in HIV-1 RNA levels at 6 months. The primary outcome was virologic success, defined as achieving an HIV-1 RNA level ≤400 copies/mL or a ≥1.0 log10 reduction in HIV-1 RNA level. A second analysis consisted of linear regression assessing the effect of covariates on log10 HIV-1 RNA reduction from baseline to 6 months. RESULTS: In multivariate analyses, achieving virologic success at 6 months was associated with high medical services utilization [adjusted odds ratio [AOR] = 10.0 (1.4, 73.9); P = 0.02] and with the use of case management services [AOR = 5.8 (1.1, 30.5); P = 0.04]. Both services resulted in a larger reduction in log10 HIV-1 RNA from baseline (difference in slopes: -0.9 and -1.0, respectively; P = 0.02 for both). Referral to off-site substance abuse services treatment did not significantly predict either virologic outcome. CONCLUSIONS: Among individuals who receive DAART, the utilization of on-site medical and case management services was independently associated with improved virologic outcomes. These results suggest the potential utility of integrating these services into DAART interventions (DAART-Plus) targeting HIV-infected drug users with problematic adherence.