Risk Factors Associated with Loss to Follow-up Among Transgender Women Receiving HIV Pre-exposure Prophylaxis in Chiang Mai province, Thailand

Although HIV pre-exposure prophylaxis (PrEP) is free in Thailand, many transgender women discontinue taking it after initiation. We determined the loss to follow-up (LTFU) rate of transgender women who initiated PrEP at the Mplus Foundation, Chiang Mai, Thailand, and identified associated risk factors using Cox proportional hazard models. Of 235 participants who initiated PrEP, 59 (55%) out of 108 remaining participants had reactive syphilis. The LTFU rate at 6 months was 38% (95% confidence interval [CI]: 29–48%). Multivariable analysis indicates that LTFU is independently associated with age ≥ 26 years old (adjusted hazard ratio [aHR] = 2.09; 95% CI: 1.06–4.14) and reactive syphilis (aHR = 1.98; 95% CI:1.01–3.88). Delayed appointment scheduling by the PrEP providers and the syphilis clinic was associated with transgender women having reactive syphilis, and the lockdown policy during the COVID-19 pandemic might have influenced them to discontinue PrEP and their subsequent LTFU.