Table 5. Performance of selected comorbidity measures in assessing the association between comorbidity and selected outcome measures (Victoria).

Model	Ln (ICU1 hours)2		Ln (MV3 hours)4		Number of complications5
	Adjusted R2	Model fit AIC	Adjusted R2	Model fit AIC	Mc. Fadden's Adjusted R2	Model fit AIC
(i) Baseline model	0.104	14591	0.145	7815	0.029	106849
(ii) Baseline model + selected comorbidities (individually modelled with binary representation)	0.121	14498	0.164	7763	0.036	106142
(iii) Baseline model + selected comorbidities (modelled as a weighted summed score)6	0.121	14492	0.152	7795	0.032	106584
(iv) Baseline model + comorbidity using CCI weights	0.108	14572	0.147	7809	0.031	106639
(v) Baseline model + comorbidity using Quan weights	0.107	14577	0.147	7810	0.030	106720
(vi) Baseline model + ECM	0.130	14471	0.178	7752	0.036	106103

1. ICU–intensive care unit

2. Baseline model includes age, sex, injury severity, injury type and body region; outcome = ICU stay hours (Ln transformed linear model)

3. MV–mechanical ventilator

4. Baseline model includes age, sex and injury severity; outcome = MV hours (Ln transformed linear model)

5. Baseline model includes age, sex, injury type, injury severity and body region; outcome = number of complications for those with at least one complication (negative binomial model)

6. See Methods for weight calculation, excludes weights resulting from an odds <1.2, rounded weights used

See Table 6 for selected comorbidities for each outcome