Table 2.

Area under the ROC curve and optimal cutoff value of variables indicating acute respiratory distress syndrome in COVID-19.

	AUROC	P value	95% CI	Cutoff value	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)
Continuous variables
C-reactive protein (mg/dL)	0.90	<0.001	0.85–0.94	5.0	94	74	51	98
Infiltration on chest X ray (%)	0.87	<0.001	0.81–0.94	22	74	84	57	91
Neutrophil/lymphocyte ratio	0.87	<0.001	0.80–0.93	3.55	90	71	47	97
Lymphocyte count (/mm3)	0.81	<0.001	0.74–0.88	1021	70	74	44	90
Neutrophil count (/mm3)	0.77	<0.001	0.68–0.86	5373	67	82	43	90
Age (year)	0.80	<0.001	0.72–0.87	60	92	53	35	96
Lactate dehydrogenase (U/L)	0.74	<0.001	0.64–0.85	600	71	65	37	89
Aspartate transaminase (U/L)	0.73	<0.001	0.64–0.83	41	70	71	41	89
Platelet (×103/mm3)	0.72	<0.001	0.63–0.81	204	57	60	29	83
Glucose (mg/dL)	0.72	<0.001	0.63–0.81	125	75	66	40	90
Blood urea nitrogen (mg/dL)	0.68	0.001	0.56–0.79	14.6	62	63	33	85
Body mass index (kg/m2)	0.65	0.010	0.55–0.75	24.2	66	67	32	88
Creatinine (mg/dL)	0.62	0.023	0.51–0.73	0.83	60	60	30	84
Categorical variables
Dyspnea	0.67	0.002	0.57–0.77		70	64	36	88
Hypertension	0.64	0.011	0.53–0.74		57	71	36	85
Headache	0.63	0.015	0.54–0.73		89	37	8	71
Diabetes mellitus	0.60	0.059	0.49–0.71		35	85	41	82
Fever	0.60	0.068	0.50–0.70		84	36	27	88
Myalgia	0.60	0.059	0.50–0.70		81	39	12	72
Sore throat	0.58	0.164	0.48–0.67		95	21	7	74
Dementia	0.56	0.300	0.45–0.67		14	98	63	80
Chronic kidney disease	0.55	0.391	0.44–0.66		11	98	67	79

Acronyms: AUROC = area under the receiver operating characteristic curve; PPV = positive predictive value; NPV = negative predictive value.