Patterns of PrEP Retention among HIV Pre-exposure Prophylaxis Users in Baltimore City, Maryland

Background: HIV pre-exposure prophylaxis (PrEP) retention, defined as quarterly clinical evaluation, is critical to reducing HIV incidence. Our objectives were to determine: (1) visit- and individual-level PrEP retention patterns; (2) and individual-level characteristics associated with low-level PrEP retention 12 months after initiation among PrEP users in Baltimore City, Maryland.Methods: Information was abstracted from medical records among individuals initiating PrEP between October 1, 2015 and February 28, 2018. Visit-level PrEP retention was defined as evidence of PrEP use, documented PrEP prescription, or current PrEP use at each quarterly follow-up visit. Low-level PrEP retention was defined as <3/4 quarters with documented PrEP use. Multilevel mixed effects Poisson regression was used to determine characteristics associated with low-level PrEP retention.Results: Among 412 individuals initiating PrEP and followed for 12 months, the majority was: cis-gender male (83.7%, n = 345), non-Hispanic Black (56.3%, n = 232) and gay, bisexual, or other man who has sex with men (74.0%, n = 305). By quarterly visits, PrEP retention was: 3-month: 69.4% (n = 286); 6-month: 51.9% (n = 214); 9-month: 44.5% (n = 183); and 12-month: 41.1% (n = 169). Three-fifths (58.5%, n = 241) had low-level PrEP retention. Cis-gender females (vs. cis-gender males) (adjusted relative risk: 1.36, 95% confidence interval: 1.04 to 1.77) were more likely to have low-level PrEP retention.Conclusions: Our observed PrEP retention rates are lower than what may be needed to reduce HIV incidence. Future research should examine individual- and clinic-level barriers and facilitators to PrEP retention programs by key population to inform interventions for PrEP retention.