Comparison of different comorbidity measures for use with administrative data in predicting short- and long-term mortality

Table 2 G² statistics indicating the contribution of the comorbidity measures to the nested baseline model

	G^2†(df^‡)
	In-hospital mortality		One-year mortality
	AMI	COPD	AMI	COPD
Baseline model*	N/A(4)	N/A (4)	N/A (4)	N/A (4)
Index hospitalization only
Baseline model + Charlson/Deyo	35 (16)	59 (17)	120 (16)	254 (17)
Baseline model + Charlson/Romano	100 (15)	114 (16)	280 (15)	613 (16)
Baseline model + Elixhauser	216 (33)	269 (33)	394 (33)	856 (33)
Index and prior hospitalizations
Baseline model + Charlson/Deyo	80 (19)	98 (20)	336 (19)	1106 (20)
Baseline model + Charlson/Romano	129 (19)	144 (20)	428 (19)	1199 (20)
Baseline model + Elixhauser	194 (33)	200 (33)	496 (33)	1290 (33)

AMI = acute myocardial infarction; COPD = chronic obstructive pulmonary disease.
* Variables in the baseline model included age, sex, race, and whether the patient received surgery.
^† All p values of the G² statistics, < 0.0001.
^‡ Degree of freedom equals to the number of parameters entered in the regression model. Some comorbidity variables were dropped in the analysis because they had 0% or 100% prevalence.
N/A: Not applicable.

ISSN: 1472-6963