Incarceration history and HIV testing among people who inject drugs in the Boston metro area: a pooled cross-sectional study.

Background: The persistent incidence of HIV among people who inject drugs (PWID) underscores the urgency for HIV prevention efforts to end the HIV epidemic. Little is known about the role carceral settings play as touchpoints for HIV testing in this population. Methods: Secondary analysis of cross-sectional survey data of PWID in the Boston metro area from the 2015 and 2018 cycles of the National HIV Behavioral Surveillance (NHBS). Among self-reported HIV-negative participants, we examined incarceration and HIV testing histories and used a multivariable modified Poisson regression model to evaluate the association between incarceration history (main exposure) and past-year HIV testing (primary outcome). Results: Among 957 participants, average age was 38.9 (SD 11.1) years, 70.1% were male, 15.2% were Hispanic (of any race), 8.4% were non-Hispanic Black, and 68.1% were non-Hispanic White. Regarding incarceration experiences, 43.5% of participants reported past-year incarceration, and 41.8% reported a history of incarceration but only prior to the past year. Among those with past-year incarceration, 23.4% said their last HIV test was done at a jail or prison. Adjusting for other characteristics, compared to no incarceration history, past-year incarceration (PR 1.39; 95% CI: 1.29, 1.49) and incarceration prior to the the past year (PR 1.19; 95%CI: 1.02, 1.38) were both associated with a greater prevalence of past-year HIV testing. Conclusions: Among PWID, incarceration was very common and was a substantial source of HIV testing. However, more testing is still needed-in both community and carceral settings-to reach optimal testing rates in this key population.