Table A1.

Multivariable generalized linear model for hospital volume.

	Coefficient	95% CI		P-value
Volume
Low Volume	Reference
High Volume	−1175.07	−3254.41	−904.27	0.27
Age	2.41	−16.88	21.71	0.81
Sex
Female	Reference
Male	−1745.26	−2109.33	−1381.19	<0.001
Race
Caucasian	Reference
African American	122.97	−643.33	889.27	0.75
Asian	2820.01	1099.81	4540.21	0.001
Other	2366.10	1017.35	3714.85	0.001
Unknown	−1443.85	−3071.53	183.83	0.08
Severity of Illness
Minor	Reference
Moderate	2550.67	2089.95	3011.39	<0.001
Major	7782.20	6988.73	8575.67	<0.001
Extreme	43212.74	36284.23	50141.26	<0.001
Unknown	3553.20	2521.07	4585.33	<0.001
Pancreaticoduodenectomy	3114.89	2498.07	3731.71	<0.001
Minimally invasive operation	−1377.41	−2108.42	−646.39	<0.001
Payer
Private	Reference
Government	503.59	−9.29	1016.48	0.05
Other	−148.71	−1547.74	1250.32	0.84
Elixhauser comorbidity index score	78.00	45.81	110.19	<0.001
Time-period
10–2013 to 9–2014	Reference
10–2014 to 9–2015	253.85	−308.04	815.75	0.38
10–2015 to 9–2016	1919.82	1076.54	2763.09	<0.001
10–2016 to 6–2017	1776.41	977.35	2575.46	<0.001