Rural and urban comparisons of polysubstance use profiles and associated injection behaviors among people who inject drugs in Puerto Rico

Introduction: In contrast to urban populations, little is known about polysubstance.use among rural people who inject drugs (PWID), particularly in Puerto Rico where injection drug use and related health consequences are prevalent. The aim of the study is to compare injection and non-injection substance use profiles among separate urban and rural samples of Puerto Rican PWID. Material and methods: Data for the urban sample come from 455 PWID who participated in the CDC's National HIV Behavioral Surveillance survey of injection drug use in San Juan. The data for the rural sample come from 315 PWID residing in four rural cities approximately 40-miles from San Juan. Latent class analysis was used to derive separate urban and rural profiles of weekly injection and non-injection substance use. Injection behaviors were examined as possible correlates of latent class membership. Results: Five latent classes were identified in the urban sample, and three latent classes were identified in the rural sample. Classes were similar across samples; however, key differences emerged. Both samples had classes of primary heroin injectors, primary speedball injectors, and cocaine-heroin injectors. The urban sample had one high polysubstance class. Polysubstance use profiles that shared similar characteristics between samples also shared similar injection patterns, with some variation. Discussion: Variations in substance use patterns and associated health risks are likely shaped by social and geographic boundaries. Conclusions: Understanding variations in substance use patterns across rural and urban locales may improve surveillance efforts and tailor desistance and harm reduction efforts at the state and local levels.