Table 3. Socioeconomic and Regulatory Factors Contributing to the Association of the Vote for the Republican Presidential Candidate in 2016 With Rates of Chronic Opioid Prescriptions .

Socioeconomic or Regulatory Factora	R2		Parameter Estimateb	Standard Error	P Value
	Model	Partial
Model 1	0.18
Intercept			7.50	0.23	<.001
% Republican presidential vote		0.18	0.09	0.004	<.001
Model 2	0.44
Intercept			13.65	1.98	<.001
% Republican presidential vote (each 1% increase)		0.07	0.08	0.005	<.001
% Original entitlement as disabled (1% increase)		0.04	0.12	0.01	<.001
Median household income, per $1000 (1% increase)		0.02	−0.05	0.007	<.001
% Part D coverage (1% increase)		0.02	−0.07	0.009	<.001
Unemployment (1% increase)		0.01	0.13	0.02	<.001
% With ≥3 comorbidities (1% increase)		0.007	−0.05	0.01	<.001
% Adult high school graduate (1% increase)		0.007	−0.05	0.01	<.001
% Married (1% increase)		0.003	0.04	0.01	.001
Ruralityc (1 unit increase)		0.003	−0.07	0.02	.004
% Single household (1% increase)		0.002	0.04	0.02	.02
% HMO (1% increase)		0.002	−0.01	0.004	.03
% Non-Hispanic white (1% increase)		0.001	0.009	0.006	.13
% Medicaid eligible (1% increase)		<0.001	−0.01	0.01	.35
% Male (1% increase)		<0.001	0.01	0.02	.46
Religious attendance per 1000 population (1% increase)		<0.001	<.001	<.001	.88
Model 3	0.46
Intercept			12.05	1.98	<.001
% Republican presidential vote		0.06	0.08	0.005	<.001
% Original entitlement as disabled		0.05	0.12	0.01	<.001
Median household income, per $1000		0.02	−0.05	0.007	<.001
% Part D coverage		0.02	−0.07	0.009	<.001
Unemployment		0.008	0.10	0.02	<.001
% With ≥3 comorbidities		0.009	−0.06	0.01	<.001
% Adult high school graduate		0.004	−0.04	0.01	<.001
% Married		0.003	0.04	0.01	.001
Ruralityc		<0.001	−0.02	0.03	.32
% Single household		0.003	0.06	0.02	.002
% HMO		<0.001	−0.007	0.004	.13
% White		0.001	0.01	0.006	.04
% Medicaid eligible		<0.001	−0.01	0.01	.26
% Male		<0.001	0.001	0.02	.97
Religious attendance per 1000 population		<0.001	<.001	<.001	.12
Opioid law category, yes vs nod
1		0.007	0.94	0.20	<.001
2		0.003	0.37	0.12	.002
3		0.002	−0.36	0.13	.006
4		0.002	0.25	0.01	.01
5		<0.001	−0.16	0.14	.24
6		<0.001	−0.26	0.32	.42
7		<0.001	0.40	0.34	.25

Abbreviation: HMO, health maintenance organization.

^aThe county opioid rates are adjusted for the individual characteristics of Medicare enrollees (shown in Table 1). Model 1 includes only the county percentage vote for the Republican presidential candidate. Model 2 adds county-level socioeconomic measures. Model 3 adds whether the state had specific regulations on opioid prescribing.

^bParameter estimate is the change in response (rate of opioid prescriptions) for each 1-unit change in the predictor.

^cRurality is measured by the US Department of Agriculture Rural-Urban Continuum Codes²¹: 1 indicates counties in metropolitan areas of 1 million population or more; 2, counties in metropolitan areas of 250 000 to 1 million population; 3, counties in metropolitan areas of fewer than 250 000 population; 4, urban population of 20 000 or more, adjacent to a metropolitan area; 5, urban population of 20 000 or more, not adjacent to a metropolitan area; 6, urban population of 2500 to 19 999, adjacent to a metropolitan area; 7, urban population of 2500 to 19 999, not adjacent to a metropolitan area; 8, completely rural or less than 2500 urban population, adjacent to a metropolitan area; 9, completely rural or less than 2500 urban population, not adjacent to a metropolitan area.

^dThe state laws are classified into 7 categories by the Centers for Disease Control and Prevention.²² See Methods for description.