The cost and cost-effectiveness of an enhanced intervention for people with substance abuse problems at risk for HIV

Objective. To estimate the costs, effectiveness, and cost-effectiveness of prevention interventions for out-of-treatment substance abusers at risk for HIV This is the first cost-effectiveness study of an AIDS intervention tha t focuses on drug use as an outcome. Study Design. We examined data from the North Carolina Cooperative Agreemen t site (NC CoOp). All individuals in the study were given the revised NIDA standard intervention and randomly assigned to either a longer, more person alized enhanced intervention or no additional intervention. We estimated th e cost of each intervention and, using simple means analysis and multiple r egression models, estimated the incremental effectiveness of the enhanced i ntervention relative to the standard intervention. Finally, we computed cos t-effectiveness ratios for several drug use outcomes and compared them to a "back-of-the-envelope" estimate of the benefit of reducing drug use. Principal Findings. The estimated cost of implementing the standard interve ntion is $187.52, and tile additional cost of the enhanced intervention is $124.17. Cost-effectiveness ratios range from $35.68 to $139.52 per reduced day of drug use, which are less than an estimate of the benefit per reduce d drug day. Conclusions. The additional cost of implementing the enhanced intervention is relatively small and compares favorably to a rough estimate of the benef its of reduced days of drug use. Thus, the enhanced intervention should be considered an important additional component of an AIDS prevention strategy for out-of-treatment substance abusers.