Table 3 Risk factors significantly associated in multivariate analyses with mortality within 90 days of hospital discharge in the derivation cohort (n = 1117)

Risk factors	β parameter	OR (95% CI)	p Value	Points
Intercept	−5.33
Baseline functional status*
16–30 vs 15	1.26	3.51 (0.96 to 12.79)	0.06	3
>30 vs 15	2.61	13.62 (3.96 to 46.85)	<0.001	6
Charlson index
>1 vs 0+1	0.87	2.38 (1.24 to 4.59)	0.009	2
CURB score†
>1 vs 0+1	0.79	2.20 (1.16 to 4.15)	0.01	2
AUC		0.81
Hosmer–Lemeshow p value‡		0.910

All risk factors were examined jointly.
n = 1033 (45 deaths, 988 survivors). No answers were received to Katz index for 84 cases (10 deaths).
*Baseline functional status was measured by the Katz index (n = 1036); functional status range 15–52 (excellent functional status, 15).
†Severity of illness on admission was assessed with the CURB score (Confusion, Urea nitrogen, Respiratory rate, Blood pressure).
‡A significant value for the Hosmer-Lemeshow statistic indicates a significant deviation between predicted and observed outcomes.
AUC, area under the receiver operating characteristic curve; OR, odds ratio; 95% CI, 95% confidence interval; β parameter, estimated β coefficient.