Table 3.

Modeled Relationship Between Physician Density and Percent Uninsured by Region and Medicaid Expansion.

Geographic area	Medicaid expansion			No Medicaid expansion			P valuea
	Log (OR)	25th-75th percentilesb	10th-90th percentiles	Log (OR)	25th-75th percentilesb	10th-90th percentiles
Preexpansion
Nation	−1.77**	−9.28	−15.49	−1.67**	−8.14	−16.01	.75
Northeast	−1.18*	−2.89	−5.22	−5.71	−6.56	−11.64	.73
Midwest	−0.92	−2.61	−4.97	−3.40*	−12.14	−22.18	.13
South	−4.30**	−11.84	−23.90	−1.46**	−6.01	−11.93	<.01
West	−2.82**	−11.53	−21.31	3.12	14.57	25.85	.040
Postexpansion
Nation	−3.80**	−9.42	−19.44	−2.29**	−8.88	−18.38	<.01
Northeast	−1.14	−1.95	−3.43	−3.42	−1.56	−8.44	.83
Midwest	−1.87	−3.86	−7.04	−2.85	−9.84	−16.48	.62
South	−4.12**	−13.85	−20.83	−2.40**	−9.87	−17.77	.19
West	−6.48**	−20.43	−32.27	5.71	15.78	35.75	<.01
Post-Preexpansionc
Nation	−1.64**	−5.41	−8.76	−1.13	−2.00	−3.68	.53
Northeast	−2.40*	−2.34	−4.95	−3.80	−0.72	−6.22	.96
Midwest	3.01	3.31	6.66	−3.19	−3.23	−7.34	.19
South	−3.30*	−7.34	−16.15	0.63	0.92	1.81	.02
West	−2.61**	−6.20	−12.92	−1.74	−5.58	−9.56	.86

Note. Log (OR)—log (odds ratio, ie, slope coefficient) of PCP vs No PCP per unit change in Proportion Uninsured. PCP = primary care physician; CBSA = Core-Based Statistical Area.

^aP value for approximate t tests for log (OR) (slope) differences for each geographic between Medicaid expansion and No Medicaid expansion.

^b25th to 75th percentiles and 10th to 90th percentiles are expressed as the expected (modeled) difference in PCP density between CBSAs in the 25th to 75th and 10th to 90th percentiles, respectively, of percentage uninsured within geographic area and Medicaid expansion status.

^cLogit model for postexpansion year PCP density using difference in percentage uninsured between postexpansion and preexpansion periods as predictor, by region and Medicaid expansion status.

^*P < .05. **P < .01.