Urbanicity Differences for Opioid Prescribing and Overdose Deaths in Michigan: A County-Level Analysis from 2013-2017

Background and Purpose: Generally, living in a rural area represents one identified risk factor for both overdose and residing in a high-volume opioid prescribing area. Nonetheless, previous work highlights that state or regional data can diverge from general trends. Thus, there remains a need for regional research to more precisely inform local policy. Few studies have examined region-specific analyses in hot-spot overdose death regions, and few urbanicity comparisons for opioid-related overdose death or prescribing rates have been conducted in the Midwest, despite high opioid-related overdose death rates. Therefore, for both opioid-related outcomes, the present study used state-level data to examine urbanicity differences in five sequential years, as well as annual percentage changes across that timeframe.

Methods: This study used 2013-2017 county-level public data on opioid-prescribing rates and opioid-related overdose death rates (per 100,000 residents) extracted from the Michigan Department of Health and Human Services. Urbanicity was assessed by Rural Urban Continuum Codes (RUCCs) developed by the U.S. Department of Agriculture. RUCCs have nine categories and were dichotomized to urban (RUCC=1-3) and rural (RUCC=4-9). We used t-tests to examine rural/urban differences in opioid-prescribing and opioid-related overdose death rates for each year. We then used joinpoint regression analyses to test whether the annual changes in both opioid-related outcomes were statistically significant across 2013-2017 among rural and urban counties.

Results: The majority of Michigan counties were rural (n=57, 68.7%). The mean opioid-prescribing rates were 106,258 (SD=27,047), 111,855 (SD=28,458), 119,646 (SD=28,958), 116,116 (SD=27,953), and 106,421 (SD=25,751) for 2013, 2014, 2015, 2016, and 2017, respectively. The mean opioid-related overdose death rates were 6.34 (SD=5.62), 7.29 (SD=6.95), 9.65 (SD=7.78), 11.51 (SD=8.70), and 14.78 (SD=10.06) for the five sequential years, respectively. Bivariate analyses demonstrated that rural counties (vs. urban) had consistently higher opioid-prescribing rates, whereas urban counties (vs. rural) had consistently higher opioid-related overdose death rates (p<.05 for all ten t-tests). Joinpoint regression analysis revealed that there were no changes across 2013-2017 for opioid-prescribing rates among rural or urban counties. By contrast, opioid-related overdose death rates significantly increased across 2013-2017 in both rural (Annual Percent Change=24.84, p<.05) and urban counties (Annual Percent Change=22.66, p<.05).

Conclusions and Implications: There is an urgent need to expand services to hot-spot overdose death regions. Our study utilized state-level data in Michigan, a hard-hit region, to provide findings that can guide targeted service delivery efforts. Some of our findings are consistent with national trends, while others diverge. Similar to national trends, we observed upward trends in opioid-related overdose death rates regardless of urbanicity, and higher opioid-prescribing rates among rural counties. Contrary to national trends, urban counties consistently had higher opioid-related overdose death rates compared to rural counties, despite rural counties having higher opioid-prescribing rates in the same timeframe. It is plausible that unmeasured factors commonly associated with urban counties (i.e.., greater access to illicit and potent opioids, higher opioid use disorder rates) are driving differences in Michigan. We suggest policymakers in Michigan and other regions take into account both general and regional trends to better optimize service delivery efforts in their jurisdiction.