Association between county-level sociodemographic characteristics and county-level differences in opioid dispensing

Abstract

Background While overall opioid prescribing has been decreasing in the United States, the rates of prescribing at the county level have been variable. Previous studies show that social determinants of health (the social and economic conditions in which we live) may play a role in opioid prescribing; however, researchers have not examined this relationship across US counties. This cross-sectional study seeks to determine whether county-level sociodemographic characteristics (e.g., economic, housing, social environment, healthcare environment, and population characteristics) are associated with county level differences in opioid dispensing. Methods Data from 2,881 counties in the United States from 2017 to 2018 were used for this study. Opioid dispensing was measured using morphine milligram equivalents (MME) per capita. Spatial error models were used to measure the association between county-level sociodemographic characteristics and MME per capita while adjusting for spatial correlation between neighboring counties. Results In the adjusted model, counties with a higher percentage of people below the poverty line, with less than a 4-year college degree, and without health insurance were associated with higher MME dispensed per capita, as were counties with higher percentages of families headed by a single parent, persons separated or divorced, and those with disabilities. Conversely, minority race/ethnicity and rural population were associated with lower opioid dispensing. Conclusions County-level sociodemographics can differ in their association with opioid dispensing, hence examining which county-level factors help in improving opioid prescribing, and implementing overdose prevention strategies that tackle these factors is important.

Prevalence and correlates of prescription opioid use among US adults, 2019–2020

“…This finding is surprising given widespread perception of higher opioid use in rural areas, supported by studies reporting large rural/urban differences in opioid misuse and related morbidity and mortality [ 52 ]. Specifically for prescription opioid use, however, the sparse prior research yields conflicting findings: Some studies find higher POU in rural areas [ 13 , 15 ], others find lower [ 9 ], and still others find no rural/urban differences [ 5 , 12 , 53 ], as in the current study. Many accounts of the opioid epidemic focus on opioid misuse in rural areas, but our findings suggest that large and medium urban areas are not necessarily less vulnerable, at least not based on POU rates.…”

“…With respect to socioeconomic status (SES), prior work has consistently found higher POU among lower-SES adults [ 5 , 9 , 53 , 55 ]. What our analysis contributes is that food insecurity and employment status are more salient predictors of POU use than the more commonly used SES measures of education or income, which were largely not significant net of these other covariates.…”

“…First, many recently published studies on POU among US adults are based on data over a decade old [ 5 – 8 ]. Given the dramatic changes in opioid prescribing in recent years [ 9 ] alongside increases in pain prevalence [ 1 ], information from a decade or longer ago may not reflect current POU patterns. Second, studies often utilize data that has only limited information on respondent characteristics [ 10 ], especially in pharmacy prescription-based studies [ 11 ].…”

“…This is problematic because multiple social determinants of POU are correlated, and omitting some will bias the estimates for others. For instance, rural areas have older populations with more white and US-born adults [ 13 ], lower socioeconomic status (SES) [ 14 ], and more pain [ 13 ], characteristics also associated with higher POU [ 9 , 15 , 16 ]. Thus, if not taking these correlated characteristics into account, estimates for rural/urban differences could be biased by the effects of age, race and ethnicity, SES, and/or pain differences.…”

“…Fourth, some studies use opioid dispensing information at county or state levels or other aggregate approaches, raising the risk of ecological fallacy. For instance, counties with higher proportions of uninsured adults have higher opioid dispensing amounts [ 9 ]. However, the county-level proportion of uninsured captures the county’s socioeconomic status, rather than any given individual’s access to medical care and thus to opioid prescriptions; at the individual level, the association between health insurance and opioid dosage may differ from that observed at the county level.…”