Female entertainment and sex workers (FESW) have high rates of alcohol and amphetamine-type stimulant (ATS) use, increasing risk for HIV/sexually transmitted infections (STI), and other negative outcomes. A prospective cohort of 1,198 FESW in a HIV/ATS use prevention intervention in Cambodia was assessed for alcohol and stimulant use disorders (AUD and SUD) using the Alcohol and Substance Use Involvement (ASSIST) scale. STI history was measured by self-report at baseline and at quarterly follow-up visits. Participants were asked if they had been diagnosed with an STI by a medical provider in the past 3 months. Marginal structural models were used to estimate joint effects of AUD and SUD on recent STI. At baseline, one-in-four screened AUD positive and 7% screened positive for SUD. At 18-months, 26% reported ≥1 recent STI. Accounting for time-varying and other known confounders, the adjusted odds ratio (AOR) for recent STI associated with AUD alone and SUD alone were 2.8 (95% CI:1.5-5.1) and 3.5 (95% CI:1.1-11.3), respectively. The AOR for joint effects of AUD and SUD was 5.7 (95% CI:2.2-15.2). AUD and SUD are independently and jointly associated with greater odds of STI among Cambodian FESW. Further research is critical for understanding how AUD and SUD potentiate biological and behavioural pathways that influence STI acquisition and to inform HIV risk-reduction interventions in FESW.

We examined the proportion and correlates of loss to follow-up (LTFU) among female entertainment and sex workers (FESWs) in a longitudinal HIV prevention intervention trial in Cambodia. The Cambodia Integrated HIV and Drug Prevention Intervention trial tested a comprehensive package of interventions aimed at reducing amphetamine-type stimulant use and HIV risk among FESWs in ten provinces. The present study estimated the proportion of women LTFU and assessed factors associated with LTFU. Logistic regression analyses were used. Of a total 596 women enrolled, the cumulative proportion of LTFU was 29.5% (n = 176) between zero- and 12-month follow-up. In multivariate analyses, women with no living children (adjusted odds ratio [AOR] 1.6; 95% confidence interval [CI]: 1.1, 2.3) and those who experienced recent food insecurity (AOR 1.7; 95%CI: 1.1, 2.7) were more likely to be LTFU. Women who were members of the SMARTgirl HIV prevention programme for ≥ 6 months compared to non-members were less likely to be LTFU (AOR 0.3; 95%CI: 0.2, 0.6). LTFU was moderately high in this study and similar to other studies, indicating a need for strategies to retain this population in HIV prevention programmes and research. Interventions aimed at stabilizing women's lives, including reducing food insecurity and creating communities of engagement for FESWs, should be considered.