Introduction: HIV pre-exposure prophylaxis (PrEP) significantly reduces the risk of HIV acquisition. However, studies have demonstrated discordance between self-reported measures and biomedical benchmarks of PrEP adherence. We estimated the correlation between self-reported PrEP adherence and PrEP biomarkers and explored factors associated with adherence among men who have sex with men (MSM) in Nigeria.
Methods: TRUST-PrEP, an open-label, prospective study; conducted in Abuja between April 2018 and May 2019. MSM ≥ 18 years with substantial HIV risk were enrolled. Participants reported PrEP adherence in the last month using a 4-point scale from "poor" to "perfect" and serum samples for PrEP biomarkers were collected at months 3 and 9. Serum tenofovir concentration was measured by liquid chromatography-tandem mass spectrometry and considered protective for adherence if ≥ 4.2 ng/ml. Spearman's rank correlation was used to estimate correlation between self-reported adherence and measured tenofovir levels. Generalized estimating equations with a logit link was used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for associations between self-reported adherence and laboratory-measured adherence.
Results: A total of 219 MSM with median age 23 (interquartile range 20-27) years had at least one PrEP biomarker assay. Only 66/219 (30%) had at least one record of protective tenofovir concentration. Correlation between tenofovir and self-reported adherence at 3 and 9 months were 0.1 and 0.02 respectively. Furthermore, 17/219 (8%,) and 49/219 (22%) had serum tenofovir of 4.2-35.4 ng/mL and ≥ 35.5 ng/mL, corresponding to at least 4 and 7 days' PrEP use in a week, respectively. PrEP adherence was higher among participants introduced to PrEP in the clinics compared with communities (aOR: 8.35, 95%CI: [3.24, 21.5]) and those with same-sex practices family disclosure (aOR: 3.60 95% CI: [1.73, 7.51]).
Conclusion: Self-reported PrEP adherence poorly correlated with biomarkers. Facilitating clinic-based PrEP introduction and disclosure of same-sex practices to family among MSM may improve PrEP adherence.
Copyright: © 2023 Adeyemi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.