Table 1.

Patient demographic characteristics, comorbid conditions and baseline physical examination findings

Characteristics	Derivation sample	Validation sample	P value
	(n = 4593)	(n = 1967)
Demographic factors
Male gender, n (%)	2428 (52.9)	1040 (52.9)	0.99
Age, mean (SD), years	60 (20)	60 (20)	0.48
Comorbid conditions, n (%)
Neoplastic disease	229 (5.0)	120 (6.1)	0.06
Liver disease	71 (1.5)	30 (1.5)	0.95
Congestive heart failure	542 (11.8)	235 (11.9)	0.87
Renal disease	243 (5.3)	112 (5.7)	0.51
Coronary artery disease	792 (17.2)	318 (16.2)	0.29
Chronic pulmonary disease	1153 (25.1)	474 (24.1)	0.39
Diabetes mellitus	672 (14.6)	284 (14.4)	0.84
Physical examination findings
Altered mental status, n (%)	275 (6.0)	120 (6.1)	0.96
Respiratory rate, median (IQR), per minute	22 (20 to 26)	22 (20 to 26)	0.72
Pulse, median (IQR), per minute	97 (84 to 112)	97 (84 to 110)	0.28
Systolic BP, median (IQR), mmHg	132 (118 to 150)	131 (118 to 150)	0.67
Temperature, median (IQR), °C	37.7 (36.8 to 38.5)	37.6 (36.8 to 38.5)	0.07
Oxygen saturation, median (IQR), %	94 (90 to 96)	94 (91 to 97)	0.07

Missing values were assumed to be normal for respiratory rate (n = 819; 12%), pulse (n = 356, 5%), systolic (n = 314, 5%), temperature (n = 323, 5%) and comorbid conditions (< 2%). BP = blood pressure; ICU = intensive care unit; IQR = interquartile range.