Table 1.

Multivariable regression model of in-hospital mortality and length of stay

In-hospital mortality	Odds ratios	Lower 95%	Upper 95%	P value
Yearly mean volume (per patient)	0.992	0.989	0.995	<.0001
Relative volume	1.003	0.997	1.008	.3899
Calendar year	0.952	0.916	0.989	.0107
Gender (male)	1.753	1.435	2.142	<.0001
Age (per 10 y)	1.628	1.482	1.788	<.0001
Charlson = 1	0.396	0.227	0.694	.0009
Charlson = 2	0.27	0.205	0.356	<.0001
Charlson = 3	0.402	0.292	0.555	<.0001
Charlson = 4	1.371	0.832	2.258	.2064
Charlson = 5	0.258	0.169	0.393	<.0001
Charlson = 6 +	1.009	0.535	1.9	.9785

Length of stay	Odds ratios	Lower 95%	Upper 95%	P value
Yearly mean volume (per patient)	0.997	0.996	0.999	<.0001
Relative volume	0.998	0.997	0.999	.0005
Calendar year	0.982	0.979	0.986	<.0001
Gender (male)	1.033	1.016	1.05	.0001
Age (per 10 y)	1.098	1.09	1.105	<.0001
Charlson = 1	1.087	1.039	1.137	.0001
Charlson = 2	1.003	0.974	1.034	.4097
Charlson = 3	0.998	0.964	1.033	.4436
Charlson = 4	1.369	1.26	1.487	<.0001
Charlson = 5	1.037	0.998	1.078	.0297
Charlson = 6 +	1.39	1.273	1.518	<.0001