Predictors and moderators of outcomes of HIV/STD sex risk reduction interventions in substance abuse treatment programs: A pooled analysis of two randomized controlled trials.

This CTN ancillary investigation aimed to examine predictors and moderators of response to two HIV sexual risk interventions of different content and duration for individuals in substance abuse treatment programs. Participants were recruited from community drug treatment programs participating in the National Drug Abuse Treatment Clinical Trials Network (CTN). Data were pooled from two parallel randomized controlled CTN studies, CTN-0018 and CTN-0019 (“Reducing HIV/STD Risk Behaviors: A Research Study for Men/Women in Drug Abuse Treatment”), each examining the impact of a multi-session HIV education intervention, on the degree of reduction in unprotected sex from baseline to 3- and 6-month follow-ups. The findings were analyzed using a zero-inflated negative binomial (ZINB) model.

Severity of drug use, gender, and age were significant main effect predictors of number of unprotected sexual occasions (USOs) at follow-up in the non-zero portion of the ZINB model (men, younger participants, and those with greater severity of drug/alcohol abuse have more USOs). Monogamous relationship status and race/ethnicity were significant predictors of having at least one USO vs. none (monogamous individuals and African Americans were more likely to have at least one USO). Significant moderators of intervention effectiveness included recent sex under the influence of drugs/alcohol, duration of abuse of the primary drug, and Hispanic ethnicity.

Conclusions: These predictor findings and moderator findings point to ways in which patients may be selected for the different HIV sexual risk reduction interventions and suggest potential avenues for further development of the interventions for increasing their effectiveness within certain subgroups, with particular attention to cultural sensitivity.

Related protocols: CTN-0018, CTN-0019