Table 3.

Results of Hierarchical Multivariable Regression, Assessing Association between In-Hospital Mortality and Hospital Annual Volume

Year	Volume Effect	SE	p-Value	OR	95% CI
Annual volume as a continuous variable (per 100 patients per year)
1998	−0.039	0.027	0.154	0.962	0.912–1.015
1999	−0.046	0.019	0.017	0.955	0.920–0.991
2000	−0.060	0.025	0.020	0.942	0.897–0.989
2001	−0.067	0.027	0.015	0.935	0.887–0.986
2002	−0.055	0.027	0.041	0.946	0.899–0.997
2003 (v)*	−0.007	0.032	0.826	0.993	0.932–1.058
2003 (m)†	−0.003	0.030	0.911	0.997	0.939–1.058
2004 (v)*	−0.026	0.034	0.448	0.974	0.911–1.042
2004 (m)†	−0.016	0.037	0.658	0.984	0.915–1.058
Annual volume >250 (<250 is reference group)
1998	−0.077	0.155	0.619	0.926	0.684–1.254
1999	−0.199	0.112	0.079	0.820	0.659–1.020
2000	−0.423	0.132	0.002	0.655	0.506–0.849
2001	−0.348	0.143	0.017	0.706	0.534–0.934
2002	−0.292	0.132	0.031	0.747	0.576–0.968
2003 (v)*	0.007	0.159	0.965	1.007	0.737–1.376
2003 (m)†	0.086	0.141	0.544	1.089	0.827–1.435
2004 (v)*	−0.001	0.160	0.995	0.999	0.731–1.366
2004 (m)†	0.163	0.162	0.317	1.177	0.856–1.618
Annual volume >450 (<450 is reference group)
1998	−0.286	0.203	0.164	0.751	0.505–1.119
1999	−0.263	0.140	0.064	0.769	0.584–1.011
2000	−0.323	0.202	0.114	0.724	0.487–1.076
2001	−0.533	0.204	0.011	0.587	0.394–0.873
2002	−0.327	0.174	0.064	0.721	0.513–1.013
2003 (v)*	0.050	0.208	0.810	1.052	0.699–1.582
2003 (m)†	0.016	0.206	0.940	1.016	0.678–1.522
2004 (v)*	−0.106	0.204	0.605	0.900	0.603–1.341
2004 (m)†	−0.050	0.231	0.829	0.951	0.605–1.495

Reported are the coefficients and statistics for volume, years 2000–2004. Data for covariates are not shown.

^*2003 (v) and 2004 (v) = 2003 and 2004 data from the hospitals that participated at least 1 year in the voluntary reporting program.

^†2003 (m) and 2004 (m) = 2003 and 2004 data from the hospitals that participated in the mandatory reporting program.

CI, confidence interval.