Comparing PrEP adherence via objective and self-reported measures among fishermen working on Lake Victoria, Kenya

Fishermen working along Lake Victoria experience high rates of HIV acquisition that can be mitigated by pre-exposure prophylaxis (PrEP), which requires adequate adherence for effective prevention. We evaluated PrEP adherence among Kenyan fishermen using objective metrics and examine non-adherence. Data are from the Owete study (NCT04772469), a cluster randomized-controlled trial using a social network approach among fishermen to increase HIV testing and linkage to care. Survey and lab data were collected from PrEP users. We measured recent objective adherence via a point-of-care tenofovir urine assay. We conducted a logistic regression to assess the relationship between self-reported adherence data and urine tenofovir detection. Among 71 PrEP users, 34% self-reported ≥90% PrEP adherence. Reasons for non-adherence included not feeling at risk (31%), being away and without medication (27%), or feeling they did not need PrEP (24%). Detectable PrEP in urine was low (17%). Self-reported PrEP non-adherence within 30 days was associated with 13.29 times the odds of non-detection of urine tenofovir (95% CI: 2.20, 80.43). The point-of-care tenofovir assay was a valuable tool for objectively measuring PrEP adherence. Interventions to bolster PrEP adherence are needed to prevent HIV acquisition among fishermen, as are longer-acting products with lower demands for adherence.