Risk factors for loss to follow-up of persons who inject drugs enrolled at syringe services programs in Kentucky

Background: Syringe services programs (SSP) are an effective strategy to reduce blood-borne infections of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) in persons who inject drugs (PWID). The objectives of this study were to determine the frequency and risk factors for loss to follow-up (LTFU) in PWID enrolled at SSPs in Kentucky. Methods: A retrospective cohort study was conducted which included data of PWID enrolled at 32 SSP. Demographics, use of drugs, HIV testing, HCV testing, and medical services were analyzed. A generalized linear model (GLM), family binomial was used to determine risk factors for LTFU. Results: The analysis included 5742 PWID. LTFU by year of enrollment was 287/770 (37.3%) in 2017, 796/1874 (42.5%) in 2018, and 1479/3,098 (47.7%) in 2019. LTFU was significantly associated with distance to SSP from home of more than five miles (RR 1.25; 95%CI 1.09–1.43; p = 0.002) and SSPs housed in rural counties (RR 1.22; 95%CI 1.06–1.40; p = 0.004), adjusted by age, sex, and race. The use of buprenorphine was associated with less risk of LTFU (RR 0.79, p = 0.034). Conclusion: The distance to an SSP from home and SSPs in rural counties were identified as risk factors for LTFU. Initiatives that bring health services closer to PWID homes and offer opioid use disorder treatment may improve repeated participation in SSPs.