Correlates of disparities in syringe return ratios: A cross-sectional study of a syringe services program in New York

Predictors of syringe exchange behavior are critical to informing secondary prevention measures needed to attenuate risk of blood-borne infections among persons who inject drugs (PWID).

Participants included PWIDs who attended a syringe services program in New York from 2015 to 2017 (n = 1777). We analyzed the syringe return ratio (receipts/returns) with two distinct but related methodological strategies-threshold logistic regression and quantile regression-to identify correlates of disparities in syringe return ratios.

The majority of participants were white males negative for HIV (90% white, 63% male, 76% HIV-). Logistic and quantile regression models showed that the correlates of disparate syringe return ratios (i.e., magnitude and directionality of differences) changed across different percentile groups and quantile levels, respectively. At the median threshold, being single, urbanicity, and older age were associated with higher return ratios. Syringe return ratio disparities were more pronounced among subgroups of nontypical PWIDs (with extremely low or high return ratios) especially by urbanicity, race, relationship status, and type of housing.

Irrespective of urbanicity classification, correlates of syringe return ratios such as older age, Black race, single relationship status, and unstable housing appear to be critical to informing targeted secondary prevention initiatives that promote harm reduction behavior.