Longitudinal assessment of the effects of drug and alcohol abuse on HIV-1 treatment outcomes in an urban clinic

OBJECTIVE: To assess the temporal association of changes in substance abuse with antiretroviral therapy use and adherence, HIV-1 RNA suppression, and CD4 cell count changes in patients attending an urban clinic. DESIGN: Prospective cohort study. METHODS: Six-hundred and ninety-five HIV-1-infected individuals, who completed two or more semi-annual standardized surveys and in whom antiretroviral therapy was indicated, were included in the analysis. Surveys addressed antiretroviral therapy use and adherence, and use of illicit drugs and alcohol. Substance abuse was defined as active heroin, cocaine, or heavy alcohol use in the 6 months preceding survey. The units of analysis were consecutive pairs of surveys (couplets) in individual participants. Couplets in which participants denied substance abuse in both surveys were compared to couplets in which participants switched from non-use to substance abuse, and couplets in which participants reported substance abuse in both surveys were compared to couplets where participants switched from substance abuse to non-use. RESULTS: Switching from non-use to substance abuse was strongly associated with worsening antiretroviral therapy use and adherence, less frequent HIV-1 RNA suppression, and blunted CD4 cell increases, compared to remaining free of substance abuse. Alternatively, switching from substance abuse to non-use was strongly associated with improvements in antiretroviral therapy use and adherence, and HIV-1 treatment outcomes, compared to persisting with substance abuse. CONCLUSIONS: This longitudinal study highlights the dynamic nature of substance abuse and its temporal association with the effectiveness of HIV-1 treatment in patients attending an inner-city clinic.