Sociodemographic, behavioral, and geospatial factors associated with syringe services program use in San Francisco,...

Syringe services programs (SSPs) are a cornerstone of preventing infectious disease and overdose for people who use drugs. Given efforts to achieve universal access, we examined factors associated with SSP use, including proximity.

We used cross-sectional data from 713 people who use drugs across San Francisco, California (September 2023-September 2024). We assessed proximity to an SSP by calculating the walking time between where participants slept the night before and nearest SSP location. We conducted multivariable negative binomial models to explore factors associated with SSP use and assess whether the association between proximity and SSP use was modified by race-ethnicity.

Almost 80 % of participants used an SSP at least once in the past 3 months. Age, race-ethnicity, mode of use, and proximity to SSP were negatively associated with SSP use. Participants who only smoked used SSPs less often than those who used in other ways (adjusted rate ratio [aRR]=0.77, 95 % CI: 0.61-0.97), as well as those more than a 20-minute walk to an SSP (aRR=0.54, 95 % CI: 0.36-0.83). The effect size between walking time to SSP and SSP use was substantially larger for Black participants than non-Black (Black: aRR=0.38, 95 % CI: 0.15-0.60 vs. non-Black: aRR=0.72, 95 % CI: 0.40-1.31).

Geographic distance was a barrier to SSP use, especially for Black participants. SSPs may not reach people who only smoke drugs. SSPs should be added to areas with limited geographic access and include safer smoking supply distribution.