(see Poster Gallery) County-Level Comparisons of Addiction and Infectious Disease Treatment Services in the United States: The Cascade Effect of Increasing Rurality on Supply Disparities

Background/Objectives. Prior studies have identified rural disparities in addiction and infectious disease treatment service availability compared to urban areas of the United States. Specifically, rural counties demonstrate lower supply of addiction treatment programs and federally certified opioid treatment programs (OTPs) (Amiri et al., 2021; Jones, 2017). Additionally, rural disparities for Human Immunodeficiency Virus (HIV), Hepatitis B (HBV), and Hepatitis C (HCV) treatment facilities exist compared to urban counties (Nelson et al., 2018; Schranz et al., 2018). Despite these patterns, the literature comparing rural-urban differences for addiction and infectious disease treatment supply is scarce, especially studies using per-capita level metrics from all 50 states. To address these gaps, our objectives were to examine rural-urban differences for six measures of addiction and infectious disease treatment service supply, as well as whether the county had one form of addiction and infectious disease treatment service each (i.e., co-located treatment services). Compared to urban counties, we hypothesized that remote rural and micropolitan rural counties of the United States would have lower per-capita rates for all measures and a lower likelihood of co-located treatment service availability. We predicted a cascade effect wherein remote rural counties would demonstrate greater disparities relative to urban and micropolitan rural counties, and micropolitan rural counties would experience disparities compared to urban counties. Methods. On January 1, 2022, we extracted Federal Information Processing Series (FIPS) codes and addresses of treatment service providers from publicly-available sources (SAMHSA, CDC) and calculated county-level treatment service availability (per 100,000 residents) for three addiction (addiction treatment facility, OTPs, buprenorphine providers) and three infectious disease (facilities treating HIV, HCV, and HBV) treatment service measures. We constructed binary variables to categorize whether counties had at least one type of addiction and infectious disease treatment services. For rural-urban comparisons, we used Rural Urban Continuum Codes (USDA ERS, 2020), categorized as urban (RUCCs=1-3), micropolitan rural (RUCCs=4-7), and remote rural (RUCCs=8-9). County-level per-capita rates were collapsed. Data analyses included descriptive and group comparison tests (x², Kruskal-Wallis). Results. Across the 3,142 counties of the United States, 1,166, 1,332, and 664 were classified as urban, micropolitan rural, and remote rural, respectively. Significant group differences were observed for all measures (addiction treatment: H(2)=68.79, p<0.001; OTPs: H(2)=288.20, p<0.001; buprenorphine providers: H(2)=144.78, p<0.001; HIV: H(2)=166.75, p<0.001; HCV: H(2)=119.112, p<0.001; and HBV: H(2)=92.00, p<0.001). All post-hoc comparisons were significant (ps<.001) revealing a cascade effect in treatment service availability where remote rural < micropolitan rural < urban. Group differences were observed for county-level co-located addiction and infectious disease treatment [x²(2) =406.87, p<.001; urban=44.77%, micropolitan rural=15.69%, remote rural=8.07%]. Conclusion. People living in remote and micropolitan rural areas experience disparities in addiction and infectious disease treatment service availability, with a cascade effect where supply decreases as the level of rurality increases. Our findings represent the first rural-urban analysis of per-capita supply across a range of addiction and infectious disease treatment services in the United States. Policy changes and innovative healthcare delivery models are needed in to reduce disparities among residents of remote rural and micropolitan rural communities.