HIV Pre-Exposure Prophylaxis Service Cascade and Risk Factors Associated with Loss to Follow-Up Among Key Populations in Indonesia: Data from a Real-World Pilot Implementation 2021-2023.

The pre-exposure prophylaxis (PrEP) care cascade depicting eligibility, initiation, and continuation, as well as loss to follow-up (LTFU) among individuals taking PrEP, has not been systematically evaluated in Indonesia. We examined baseline factors associated with PrEP initiation, the PrEP care cascade, and longitudinal risk factors of LTFU in the Indonesia PrEP Pilot Program, a large-scale implementation program for key populations in Indonesia: men who have sex with men (MSM), female sex workers (FSW), people who inject drugs (PWID), transgender women (TGW), and serodiscordant partners of people living with HIV (SD-PLHIV). Of the 16,469 eligible individuals, 9,124 (55.4%) initiated PrEP (mean age 29.4 [SD 7.5], 85.9% men, 74.4% MSM, 92% from Java-Bali). PrEP initiations were significantly higher among older people, women, FSW and TGW (versus MSM), while markedly lower among PWID and SD-PLHIV and those living in provinces not covered by the program. PrEP continuations at months one and three were very low among FSW (37% and 34%, respectively). The cumulative LTFU rate at 12 months was 41.9% (95% confidence interval [CI], 40.9%-43%). Becoming LTFU was predicted by being younger, being a woman, being an FSW, living in South Sulawesi, West Java, or East Java (versus Jakarta), having no STI diagnoses, reporting consistent condom use, and having high adherence. Our findings revealed gaps in PrEP initiation, continuation, and LTFU among key populations taking PrEP in Indonesia. Targeted interventions are needed to address engagement among those likely to LTFU and populations underserved by the program to improve initiation and continuation.