BACKGROUND: Prescription opioid overdose remains a critical public health problem in Kentucky. Research has shown that patients receiving high daily doses of prescribed opioids are at an increased risk for unintentional overdose. Counties in Kentucky Appalachia have been historically among the counties with highest opioid prescribing rates in the U.S. This study examined clustering of rates of patients with high daily doses of prescription opioids in Kentucky counties in 2015, and determined how socio-demographic factors were associated with the rates.
METHODS: In this ecological study with analysis units of county, Getis-Ord General G and Getis-Ord Gi* cluster statistics were performed to identify hotspots of rates of patients with at least three days per quarter receiving equal or greater than 100 daily morphine milligram equivalents (MME) for 2015 in Kentucky. The data source was the Kentucky All Schedule Prescription Electronic Reporting System (KASPER). Association between the rates of prescription opioid dispensed and selected socio-demographic factors, including per capita income, percentages of residents with bachelor degree attainment or higher, male population, and population aged 18 or older, which were obtained at county level for 2015 from the 2011-2015 American Community Survey 5-Year Estimates, United States Census Bureau, was investigated by spatial error model. Geographic variations in impacts of educational attainment were further assessed with geographically weighted regression.
RESULTS: There were significant high clusters of the rate of patients with more than three days per quarter receiving 100 daily MME or more for 2015 in Kentucky. Two hotspots were located among nine western counties on the border with Illinois and Indiana, and seven eastern counties in the Appalachian region. The spatial error model indicated that every one percent increase in bachelor degree attainment or higher was associated with a decrease in the rate of patients with more than three days per quarter receiving 100 daily MME or more by 22 per 1000 population (p-value = 0.002; R-squared = 34%). The two hotspots were also identified as the areas where educational attainment had the highest impact on the rates, suggesting improving education levels might be an effective intervention component in the areas.
CONCLUSIONS: Our study identified geographical areas in Kentucky with significantly higher rates of dispensed prescription opioids. The findings will inform local prevention and intervention efforts and additional research on risk and protective factors in the hotspots to prevent opioid dependence, misuse and overdose.