Table 3. Validation of VACO Index 30-day COVID-19 mortality estimates using area under the receiver operating characteristic curves.

	Cohort
	Development	Validation, Early	Validation, Late	Validation, Combined
Testing Dates	3/2/2020–4/15/2020	4/16/2020–5/18/2020	5/19/2020–7/18/2020	4/16/2020–7/18/2020
N	3,681	2,151	7,491	9,642
30-day Deaths, n (%)	480 (13.0)	253 (11.8)	403 (5.4)	656 (6.8)
Model, AUC (95% CI)
Age	0.77 (0.75–0.79)	0.80 (0.77–0.82)	0.83 (0.81–0.84)	0.82 (0.81–0.84)
Charlson	0.73 (0.71–0.75)	0.75 (0.72–0.78)	0.78 (0.76–0.80)	0.78 (0.76–0.80)
Index	0.79 (0.77–0.81)	0.81 (0.78–0.83)	0.84 (0.78–0.86)	0.84 (0.82–0.85)
Index Validation in Subgroups, AUC (95% CI)
Sex
Male	n/a	0.80 (0.71–0.83)	0.83 (0.81–0.84)	0.83 (0.81–0.84)
Female	n/a	0.79 (0.58–1.00)	0.91 (0.82–0.99)	0.87 (0.76–0.97)
Race/Ethnicity
Black	n/a	0.79 (0.74–0.82)	0.81 (0.78–0.84)	0.81 (0.79–0.84)
Other	n/a	0.81 (0.78–0.84)	0.84 (0.83–0.86)	0.85 (0.83–0.86)
Geographic region
Northeast & West	n/a	0.81 (0.78–0.85)	0.82 (0.80–0.86)	0.84 (0.81–0.86)
Midwest & Southeast	n/a	0.79 (0.74–0.83)	0.84 (0.83–0.86)	0.83 (0.82–0.84)

Abbreviations: AUC = Area under receiver operating characteristic curse, CI = confidence interval