Table C1.

Details on patient characteristics and CXR images.

Data	CNUH	YNU	KNUH	AMC
Details on patient characteristics
Age	47.9 $\pm$ 17.2	57.4 $\pm$ 18.5	53.8 $\pm$ 18.9	46.2 $\pm$ 14.5
Sex	Male (45.7%), Female (45.1%), N/A (9.2%)	Male (52.6%), Female (47.3%), N/A (0.2%)	Male (29.8%), Female (33.6%), N/A (36.6%)	Male (48.9%), Female (47.1%),N/A (3.9%)
COVID-19 cases	81	286	293	-
COVID-19 severity	3 (1–6)	3 (1–6)	6 (1–6)	-
CT positive cases	N/A (100%)	N/A (100%)	Positive (2.0%), N/A (98.0%)	-
Country	South Korea	South Korea	South Korea	South Korea
Details on CXR images
Number of images	365	806	1093	9972
View	PA (65.6%), AP (34.4%)	PA (56.1%), AP (43.9%)	PA (72.1%), AP (27.9%)	PA (98.7%), AP (1.3%)
Modality	CR (95.0%), N/A (5.0%)	CR (99.9%), N/A (0.1%)	CR (100%)	CR (3.7%), DX (96.3%)
Exposure time (msec)	6.7 $\pm$ 3.4	16.5 $\pm$ 7.7	12.1 $\pm$ 8.3	8.9 $\pm$ 3.9
Tube current (mA)	473.3 $\pm$ 198.1	307.8 $\pm$ 36.4	311.8 $\pm$ 39.6	298.9 $\pm$ 43.7
Bits	12 (12–14)	12 (12-12)	12 (12–14)	14 (10–15)

Note: Values are presented as mean $\pm$ standard deviation or median (range).