Cluster randomized stepped-wedge trial of a multi-level HIV prevention intervention to decrease amphetamine-type stimulants and sexual risk in Cambodian female entertainment and sex workers.

Background: HIV prevention for female entertainment and sex workers (FESW) may be optimized by addressing individual and structural risks. We examined the impact of a sequentially delivered intervention to decrease sexual risk, amphetamine-type stimulant (ATS) use, and improve economic well-being in Cambodian FESW.

Methods: A cluster randomized stepped-wedge trial was conducted in 10 Cambodian provinces to test multi-level intervention in high risk FESW. After baseline screening in 1198 women, those screening positive for ATS use disorder were allocated to a 12-week conditional cash transfer intervention followed by a 4-week cognitive-behavioural aftercare group (CCT + AC). At six months, ATS abstinent participants were offered a microenterprise (ME) opportunity. Co-primary outcomes assessed in 600 FESW at each 6-, 12- and 18-month follow-up assessments, included: 1) number of sexual partners (past three months); and 2) ATS urine toxicology positive (Tox+) results. Secondary outcomes included indicators of economic well-being.

Results: Relative to baseline, FESW reported fewer sexual partners at all follow-up assessments with a significant 50% decrease at 12-months (Adjusted Rate Ratio [ARR] = 0.50; 95%CI: 0.25, 0.95). Women had 60% lower odds of being ATS Tox+ (Adjusted Odds Ratio [AOR] = 0.40; 95%CI: 0.25, 0.65) at 6-months, and continued but non-significant reductions at 12- and 18-months. Improvements in economic well-being indicators were observed at 12- and 18-months.

Conclusions: Findings support the robust effectiveness of the sequentially delivered CCT + AC and ME interventions for boosting HIV prevention for Cambodian FESW. Further research is needed to inform the scale up and improve durability of this comprehensive approach with FESW in Southeast Asia.