Resumen
BACKGROUND: People who inject drugs (PWID) often report negative interactions with police that could elevate their risk of acquiring HIV. Some interactions can occur proximally on the causal pathway (syringe confiscation leading to syringe sharing) or distally (arrest outside methadone providers). To align policing with public health, from February 2015 ' May 2016, we trained over 1,800 police officers in Tijuana on occupational safety, drug policy reforms, and epidemiology of HIV and harm reduction services. We assessed how the training could have impacted the HIV risk environment in a parallel cohort of PWID in Tijuana. METHODS: We recruited 589 PWID by street outreach among whom 39% were female and 70% reported receptive syringe sharing at baseline. Data on police interactions were limited to visits 21 months before, 15 months during and 18 months after the training. We adopted an interrupted time series design to assess temporal trends in police interactions reported by PWID. We partitioned data into 3-month intervals which were classified into 3 periods: pre-training (7 intervals), training (5 intervals), and post-training (6 intervals). We conducted mixed effects logistic regression to estimate the mean predicted probability of the outcomes for each 3-month time interval and used these values in segmented regression to estimate the immediate change in probabilities of the outcomes from one period to the next and the change in trend within one period and the next.
RESULTS: Compared to the pre-training period, perception that participants would be arrested for carrying new syringes declined significantly during the training period (p=0.03). Further, we observed a significantly decreasing trend in the probability of syringe sharing (p=0.02) during the training period, which continued to decline in the post-training period (p=0.03). We also detected an increasing trend in the probability of accessing methadone during the training period, which marginally increased in the post-training period. CONCLUSIONS: Police trainings that integrate public health concepts could be a novel structural intervention to reduce HIV risk among PWID. Police officials should ensure that street-level officers understand how their behaviors impact health of PWID and have the capacity to refer PWID to harm reduction programs.