Table 4

Five-year centre volume and in-hospital mortality in various subgroups

Unadjusted HR (95% CI)p ValueAdjusted HR* (95% CI)p Value
Admitted via emergency department?
 Yes (n=249 722)0.895 (0.884 to 0.906)<0.0010.906 (0.894 to 0.917)<0.001
 No (n=51 250)0.799 (0.783 to 0.815)<0.0010.823 (0.806 to 0.840)<0.001
Age category
 <70 years (n=102 510)0.887 (0.865 to 0.909)<0.0010.862 (0.840 to 0.884)<0.001
 ≥70 years (n=198 462)0.892 (0.882 to 0.903)<0.0010.881 (0.870 to 0.891)<0.001
Gender
 Females (n=150 614)0.874 (0.861 to 0.887)<0.0010.883 (0.870 to 0.897)<0.001
 Males (n=150 358)0.870 (0.857 to 0.883)<0.0010.871 (0.858 to 0884)<0.001
Race
 Blacks (n=64 367)0.898 (0.872 to 0.926)<0.0010.900 (0.873 to 0.928)<0.001
 Others (n=236 605)0.975 (0.866 to 0.885)<0.0010.876(0.866 to 0.885)<0.001
Ethnicity
 Hispanics (n=30 633)0.875 (0.846 to 0.906)<0.0010.888(0.858 to 0.920)<0.001
 Others (n=270 339)0.873 (0.863 to 0.883)<0.0010.876 (0.866 to 0.886)<0.001
APR-severity of illness
 Minor/moderate (n=139 158)0.771 (0.744 to 0.798)<0.0010.796 (0.769 to 0.822)<0.001
 Major/extreme (n=161 814)0.872 (0.862 to 0.881)<0.0010.891 (0.881 to 0.901)<0.001
APR-risk of mortality
 Minor/moderate (n=163 437)0.741 (0.715 to 0.768)<0.0010.774 (0.748 to 0.802)<0.001
 Major/extreme (n=137 535)0.877 (0.867 to 0.886)<0.0010.891 (0.881 to 0.901)<0.001
Primary insurance
 Medicare/Medicaid/other federal programme (n=223 560)0.845 (0.826 to 0.865)<0.0010.883 (0.872 to 0.894)<0.001
 Other insurance (n=77 412)0.884 (0.873 to 0.894)<0.0010.854 (0.834 to 0.874)<0.001
  • Table showing Cox proportional hazard regressions for in-hospital mortality up to 120 days after admission and 5-year centre volume (measured in thousands) in various subgroups.

  • *Survival models adjusted for confounding factors—age 70 years or above, gender, black race or not, Hispanic ethnicity or not, APR-severity of illness major to extreme or not, APR-risk of mortality major to extreme or not, type of primary insurance and admission via emergency department or not. All confounders except the subgroup in which the analysis was carried were adjusted for in the adjusted HR* models.

  • APR, all patient refined.