Economic Evaluation in Hybrid Type-2 Trials: Evidence and Lessons Learned from the Substance Abuse Treatment to HIV Care Project

JESSE M. HINDE
RTI International

Given that substance use and substance use disorders among people with HIV are both prevalent and problematic, improving the integration of substance use treatment within HIV service settings is urgently needed. As part of the Substance Abuse Treatment to HIV Care Project, the Implementation & Sustainment Facilitation (ISF) strategy was found to be an effective adjunct to the Addiction Technology Transfer Center (ATTC) strategy for helping integrate a motivational interviewing-based brief intervention (MIBI) for substance use disorders. This presentation will discuss the results from the cost and cost-effectiveness study and highlight methodological considerations and lessons learned.

Thirty-nine HIV service organizations recruited in the central United States (n=14), western United States (n=11), and eastern United States (n=14). Two staff from each of the 39 HIV service organizations (N=78) were randomized to receive either the ATTC-only condition or the ATTC+ISF condition.

We estimated costs using primary data on the time spent by staff in each strategy and delivering MIBIs. We conducted staff-level cost-effectiveness analyses on the number of MIBIs implemented, average MIBI quality scores, and total client days abstinent per staff.

Per-staff costs were $3,256 for the ATTC strategy and $5,940 for ATTC+ISF, resulting in an incremental cost of $2,684. ATTC+ISF significantly increased the number of MIBIs delivered (3.73) and the average MIBI quality score (61.45), yielding incremental cost effectiveness ratios (ICERs) of $719 and $44. Client days abstinent increased between 19 and 60 days per staff, depending on the model, with ICERs ranging across models from $45 to $144. We estimated an ICER for quality-adjusted life-years, which ranged from $48,084 to $153,929.

Based on ICERs falling below the approximately $50 average reimbursement of a MIBI, the ISF strategy as an adjunct to the ATTC strategy was found to improve quality and is potentially cost-effective for days abstinent. ISF as an adjunct to the ATTC strategy may be cost-effective for improving the integration of MIBIs for substance use disorders within HIV service organizations if scaled up to reach more clients. Further, our results highlight two critical challenges in conducting cost-effectiveness analyses as part of a hybrid trial: MIBI delivery targets kept recruitment below cost-effective levels, and the definition of an aggregated days abstinent measure strongly influences interpretation. Future hybrid trials should consider these design issues to ensure robust economic conclusions can be drawn.