Detrimental effects of continued illicit drug use on the treatment of HIV-1 infection.

OBJECTIVE: To identify the effects of substance abuse status (active, former, and never) on utilization of highly active antiretroviral therapy (HAART), medication adherence, and virologic and immunologic responses to therapy. DESIGN: Prospective cohort study of 764 HIV-1-infected patients who attended an urban HIV clinic and participated in a standardized interview. MAIN OUTCOME MEASURES: Past utilization of HAART, self-reported nonadherence with antiretroviral therapy, and changes in HIV-1 RNA level and CD4+ lymphocyte count relative to prior peak and nadir, respectively. RESULTS: Forty-four percent of active drug users failed to utilize HAART compared with 22% of former drug users and 18% of non-drug users (p <.001 for both comparisons). Among participants who were taking antiretroviral therapy when interviewed, active drug users were more likely to report medication nonadherence (34% vs. 24% of nonusers and 17% of former users), had a smaller median reduction in HIV-1 RNA from baseline (0.8 log10 copies/ml vs. 1.7 in nonusers and 1.6 in former users), and had smaller median increases in CD4+ lymphocyte count from baseline (65 cells/mm3 vs. 116 in nonusers and 122 in former users) (p <.05 for all comparisons with active users). CONCLUSIONS: Active drug use was strongly associated with underutilization of HAART, nonadherence, and inferior virologic and immunologic responses to therapy, whereas former drug users and non-drug users were similar in all outcomes. Effective strategies are needed that integrate HIV-1 and substance abuse treatments.