Microsocial environmental influences on highly active antiretroviral therapy outcomes among active injection drug users: the role of informal caregiving and household factors.

Active injection drug users (IDUs) are at high risk of unsuccessful highly active antiretroviral therapy (HAART). We sought to identify baseline factors differentiating IDUs' treatment success versus treatment failure over time among those taking HAART. Interventions for Seropositive Injectors-Research and Evaluation (INSPIRE) study participants were assessed at baseline and at 6- and 12-month follow-ups. Multinominal regression determined baseline predictors of achieving or maintaining viral suppression relative to maintaining detectable viral loads over 12 months. Of 199 participants who were retained and remained on HAART, 133 (67%) had viral load change patterns included in the analysis. At follow-up, 66% maintained detectable viral loads and 15% achieved and 19% maintained viral suppression. Results indicated that those having informal care (instrumental or emotional support) were 4.6 times more likely to achieve or maintain viral suppression relative to experiencing treatment failure. Those who maintained viral suppression were 3.5 times less likely to live alone or to report social discomfort in taking HAART. Study results underscore the importance of microsocial factors of social network support, social isolation, and social stigma for successful HAART outcomes among IDUs. The findings suggest that adherence interventions for IDUs should promote existing informal HIV caregiving, living with supportive others, and positive medication-taking norms among social networks.