6ER-033 Evaluating adherence in HIV pre-exposure prophylaxis (PrEP): a retrospective analysis

<h3>Background and Importance</h3> HIV Pre-Exposure Prophylaxis (PrEP) is an established preventive therapy, made reimbursable in Italy since August 2023.¹ In this context, the prescription form was digitised with the goal of improving its clinical management and monitoring therapeutic adherence. This tool assists clinicians by streamlining the prescription process and enabling quick therapies’ monitoring for individuals at risk of HIV. However, understanding gaps between prescribed therapy and patient adherence is crucial for improving outcomes. <h3>Aim and Objectives</h3> This analysis aimed to evaluate patient adherence to PrEP, assess how well patients followed the prescribed regimen and to identify factors related to suboptimal adherence. <h3>Material and Methods</h3> Data extracted from digital form and pharmaceutical flows were crossed to create a dataset of individuals with at least one PrEP refill between July 2023 and September 2024. Only patients receiving Continuous Dosing Therapy (CDT) were included in the analysis, and those who chose On-Demand therapeutic regimen (ODT), interrupted or switched it, were excluded. Adherence was assessed by calculating the proportion of days covered (PDC),² with a threshold of ≥80% considered adherent. PDC data were compared with self-reported adherence from patients during therapeutic planning. <h3>Results</h3> A total of 515 individuals were collected, consisting of 509 males (98.8%), three females, and three with unspecified gender, with a median age of 38 years (IQR 32–46). Of these, 213 (41.4%) opted for CDT regimen, while 302 (58.6%) chose ODT regimen. The final analysed sample comprised 179 users (34.7%) who maintained the CDT, with 100% self-reported adherence. However, our analysis revealed that 21 users had a PDC ≤80%, indicating suboptimal adherence, 131 users had a PDC ≥80%, reflecting adequate adherence. Additionally, 27 users had a PDC ≥120%, suggesting potential overuse, which warrants further investigation. <h3>Conclusion and Relevance</h3> The digital prescription tool proves to be an effective system for monitoring and evaluating adherence. Despite high self-reported adherence, discrepancies between reported and actual adherence were observed, underscoring the need for continuous and objective monitoring. These findings highlight the importance of collaboration between infectious disease specialists and pharmacists to enhance clinical support. Future efforts should prioritise identifying and addressing adherence barriers while strengthening patient support to ensure sustained efficacy in HIV prevention <h3>References and/or Acknowledgements</h3> https://www.aifa.gov.it/en/-/aifa-approva-rimborsabilita-farmaci-per-la-prep McCormick <i>et al</i>. 2024. doi:10.1002/pds.5729 <h3>Conflict of Interest</h3> No conflict of interest