Estimating prevalence of opioid misuse in North Carolina counties from 2016-2021: An integrated abundance model approach.

Background: The overdose epidemic remains largely driven by opioids, but county-level prevalence of opioid misuse is unknown. Without this information, public health and policy responses are limited by a lack of knowledge on the scope of the problem.

Methods: Using an integrated abundance model, we estimate annual county-level prevalence of opioid misuse for counties in North Carolina from 2016 to 2021. The model integrates county-level observed counts of illicit opioid overdose deaths, people receiving prescriptions for buprenorphine, and people served by treatment programs. It also incorporates state-level survey estimates of misuse prevalence. County-level social and environmental covariates are also accounted for in the model. Data are integrated through a Bayesian hierarchical model to estimate posterior distributions of the parameters.

Results: In general, the estimated prevalence of misuse was decreasing over the study period. Estimated prevalence was above average in the western and southeastern parts of the state. We also estimated that the proportion of people who misuse opioids who fatally overdosed increased sharply over the study period as the median estimated proportion in 2021 was more than 8 times greater than 2016. The proportion of people who misuse opioids who received buprenorphine and were served by treatment programs increased over the study period.

Conclusions: Estimates from our integrated abundance model fill an important gap in public health knowledge about the local prevalence of people who misuse opioids and can be used to inform an adequate and equitable allocation of resources to communities across the state.