Mind the Gaps: Prescription Coverage and HIV Incidence Among Patients Receiving Pre-Exposure Prophylaxis from a Large Federally Qualified Health Center in Los Angeles, California

Abstract

Background: Understanding long-term, real world use of pre-exposure prophylaxis (PrEP) is key to improving HIV prevention. The few previous studies on PrEP continuation in community settings have identified retention as a major challenge, but data on how episodic access to PrEP affects HIV incidence has been sparse. Methods: We conducted a records-based cohort study of patients who initiated PrEP at a large federally qualified health center in Los Angeles, CA between January 2014 and December 2017. We characterized patterns of episodic PrEP use, identified correlates of PrEP discontinuation, and calculated HIV incidence. Results: Of 3,121 individuals who initiated PrEP, 42% (n=1,314) were active (i.e., had a current PrEP prescription) at the end of the analysis period. Of these, 63% (n=829) had gaps between PrEP prescriptions, averaging one gap per year (median gap length = 65 days, interquartile range = 37-129 days). HIV incidence was 0.1 cases per 100 person-years among active PrEP patients, compared to 2.1 cases per 100 person-years among patients who discontinued PrEP. Patients aged 18-24 had higher risk of discontinuation (Adjusted rate ratio (ARR) =2.8, 95% confidence interval (CI): 1.9, 4.0) compared to those aged 41-50. Compared to patients accessing PrEP through government programs with no prescription copay, risk of discontinuation was significantly higher among those with private insurance (ARR = 1.4, 95% CI: 1.2, 1.7), and those with no insurance (ARR = 4.5, 95% CI 3.2, 6.4). Conclusions: Increasing access to free or low-cost PrEP can maximize PrEP's effectiveness at reducing HIV transmission in community settings. Efforts to support PrEP continuation among young people are warranted. Funding Statement: MJ was supported by the National Institutes of Health and National Institute of Allergy and Infectious Disease, grant number K01AI091861. MRB was supported by the UCLA Postdoctoral Fellowship Training Program in Global HIV Prevention Research (Currier and Gorbach, PIs); T32MH080634. Declaration of Interests: The authors declare that there are none to report. Ethics Approval Statement: The study was approved by the Institutional Review Board at the University of California, Los Angeles (IRB#17-000717).