Table 3.

Odds ratios for rural vs. urban residence, stratified by trauma center designation, injury severity, and Census region

	Odds Ratio	95% CI	p
Trauma center designation
Level I	1.20	1.11 – 1.30	<0.001
Level II	1.34	1.16 – 1.54	<0.001
Level III	1.12	0.93 – 1.34	0.211
Level IV/non-trauma	1.23	1.15 – 1.31	<0.001
Masked I/II	1.03	0.79 – 1.34	0.831
Masked I/II/III	1.05	0.84 – 1.30	0.665
Injury severity
ISS 1–8	1.31	1.19 – 1.44	<0.001
ISS 9–15	1.10	1.03 – 1.19	0.009
ISS 16–19	1.21	1.09 – 1.35	0.001
ISS 20+	1.10	1.00 – 1.20	0.046
Unknown ISS	2.09	1.51 – 2.91	<0.001
Census Region
Northeast	1.10	0.97 – 1.24	0.125
Midwest	1.21	1.11 – 1.31	<0.001
South	1.11	1.04 – 1.18	0.002
West	1.11	0.97 – 1.28	0.130