Table 2.

Primary model – Multivariate regression of increase in drive time on inpatient mortality

	In-hospital mortality Odds Ratio (95% CI)
Decrease or no change in drive time to nearest TC (n= 266,023, 98.1%)	ref
Increase in drive time to nearest TC (n=5,122, 1.9%)	1.21 (1.04, 1.40)
COVARIATESa
Gender
Male	1.41 (1.33, 1.49)
Female	ref
Age Category
20–44 years	ref
45–64 years	1.61 (1.50, 1.72)
65–74 years	2.11 (1.89, 2.37)
75–84 years	2.78 (1.48, 3.11)
> 85 years	3.71 (3.28, 4.18)
Race/Ethnicity
Non-Hispanic White	ref
Black	0.98 (0.87, 1.10)
Hispanic	0.95 (0.87, 1.03)
Other (Asian, Pacific Islander, Native American)	0.90 (0.77, 1.04)
Insurance
Medicare	1.54 (1.39, 1.69)
Medi-Cal	1.69 (1.54, 1.86)
Private	ref
Uninsured	0.91 (0.82, 1.02)
Other	0.74 (0.65, 0.84)
Injury category
Penetrating injury	1.76 (1.62, 1.91)
Falls	ref
Burns	3.63 (2.25, 5.87)
MVC	0.84 (0.79, 0.91)
Other	0.62 (0.57, 0.68)
ISS severity
Mild	ref
Moderate	2.64 (1.23,1.37)
Severe	14.01 (13.07, 15.01)
Median household income
$14999 – 35599	1.15 (1.05, 1.27)
$35600 – 48709	1.12 (1.03, 1.22)
$48710 – 65453	1.07 (0.99, 1.16)
>$65454	ref
Trauma center in county
None	ref
Present	1.04 (0.94, 1.14)
Urbanicity
Beale=1 (most urban)	ref
Beale=2	1.07 (0.96, 1.02)
Beale=3	1.07 (0.90, 1.27)
Beale=4	0.75 (0.57, 0.98)
Beale=5	0.68 (0.25, 1.86)
Beale=6	0.81 (0.47, 1.38)
Beale=7 (most rural)	0.36 (0.15, 0.84)
Case mix index
1st quartile (0.87–1.09)	ref
2nd quartile (1.09–1.20)	0.90 (0.83, 0.98)
3rd quartile (1.20–1.34)	0.90 (0.82, 0.98)
4th quartile (>1.34)	0.80 (0.74, 0.87)
Year	0.96 (0.95, 0.97)

^aOdds ratios for patient comorbidities included in Supplemental Digital Content Table 2