Subpopulations with frequent healthcare barriers have increased risk of sexually transmitted infections and dropping out from HIV preexposure prophylaxis care.

Objective: Certain subpopulations (i.e., <25 years, transgender, sex worker, uninsured or migrant) were prioritized for inclusion in the Dutch preexposure prophylaxis (PrEP) pilot. We compared incidence of sexually transmitted infections (STI) during and drop-out from HIV PrEP care between prioritized and nonprioritized subpopulations.

Design: Retrospective longitudinal study using routinely collected data at the Centre for Sexual Health Amsterdam, 2019-2024.

Methods: We modelled incidence rates (IR) for any STI while on PrEP using Poisson regression, adjusting for testing frequency and calendar time. We modelled the probability of early loss-to-follow-up (LTFU) (i.e., no PrEP follow-up visit within 12 months of enrolment) using logistic regression, adjusting for sexual behaviour. We modelled the probability of later LTFU (i.e., no PrEP visit within 12 months of a prior PrEP follow-up visit) using competing risk regression, adjusting for sexual behaviour. We added subpopulations as indicator variables to all models to compare endpoints between groups.

Results: Of 4781 individuals included (median age 32 years, IQR = 26-40), 50.2% ( n = 2402) belonged to prioritized subpopulations. The IR of any STI was 101.6/100 person-years. STI IR were higher among those belonging to prioritized groups (except for the transgender group). 494 individuals had early LTFU, which was associated with age <25 years, reporting sex work, and being a migrant. Later LTFU occurred 933 times and was associated with age <25 years, being transgender, and reporting sex work.

Conclusion: People belonging to prioritized subpopulations had more STIs and were more often LTFU from PrEP care. Targeted interventions to support PrEP retention and prevent STIs are needed.