Table 3.

Association between hospital and physician volume and Mortality (n=7,950)

Covariates	Hospital			Surgeon
	Low	Medium	High	Low	Medium	High
	Hazard ratio (CI)	Hazard ratio (CI)	Hazard ratio (CI)	Hazard ratio (CI)	Hazard ratio (CI)	Hazard ratio (CI)
Ethnicity
African American	1.03 (0.82,1.29)	1.34 (0.83, 2.15)	0.90 (0.62,1.35)	1.14 (0.91, 1.43)	1.02 (0.63,1.64)	0.74 (0.45,1.16)
Hispanic	0.90 (0.71,1.15)	1.29 (0.83, 2.02)	1.31 (0.79,2.15)	0.95 (0.76, 1.19)	1.28 (0.77,2.10)	2.11 (1.11,3.99)
White (reference)	1.00	1.00	1.00	1.00	1.00	1.00
Age	1.02 (1.01,1.04)	1.01 (0.98, 1.04)	0.99 (0.95,1.01)	1.02 (1.01, 1.04)	0.99 (0.96, 1.03)	0.99 (0.96,1.03)
Income	1.0 (1.0, 1.0)	1.00 (1.0, 1.0)	1.00 (1.0, 1.0)	1.00 (1.0, 1.0)	1.00 (1.0, 1.0)	1.00 (1.0,1.0)
Married	0.95 (0.81,1.11)	1.24 (0.91, 1.69)	1.03 (0.74,1.43)	0.99 (0.85, 1.16)	1.09 (0.79, 1.49)	0.91 (0.63,1.32)
TNM stage
T2b –T2c	1.08 (0.93,1.27)	1.30 (1.02, 1.67)	1.07 (0.84,1.37)	1.11 (0.96, 1.27)	1.05 (0.79, 1.38)	1.27 (0.95,1.67)
≥ T3a	1.27 (1.03,1.55)	1.33 (0.89, 1.98)	1.26 (0.79,2.01)	1.37 (1.12, 1.68)	0.99 (0.66, 1.48)	1.15 (0.70,1.88)
≤ T2a (reference)	1.00	1.00	1.00	1.00	1.00	1.00
Geographic area
Metro	0.85 (0.46,1.56)	1.63 (0.39, 6.72)	0.81 (0.43,1.52)	0.87 (0.52, 1.47)	0.79 (0.32, 1.97)	1.20 (0.43,3.36)
Urban	0.93 (0.49,1.74)	2.34 (0.55, 9.85)	1.05 (0.53,2.09)	1.03 (0.59, 1.78)	0.93 (0.36, 2.36)	1.39 (0.48,4.08)
Rural (reference)	1.00	1.00	1.00	1.00	1.00	1.00
Charlson comorbidity
1–2	1.16 (0.89,1.52)	1.37 (0.87, 2.18)	1.00 (0.67,1.51)	1.16 (0.91, 1.49)	1.06 (0.69, 1.65)	1.27 (0.76,2.14)
>3	0.94 (0.61,1.44)	0.84 (0.39, 1.81)	1.14 (0.66,1.98)	0.98 (0.67, 1.45)	1.16 (0.58, 2.29)	0.81 (0.38,1.76)
(reference) 0	1.00	1.00	1.00	1.00	1.00	1.00

CI=Confidence interval