Table 2

Potential risk factors of patients with mild TBI categorized by brain CT scan results

Risk factors	CT positive (n=461)		CT negative (n=538)		P value	AuROC (95% CI)
Risk factors	N	%	N	%	P value	AuROC (95% CI)
Gender—male	176	38.2	226	42.0	0.220	0.52 (0.49 to 0.55)
Age >60 years	145	31.5	306	56.9	<0.001	0.37 (0.34 to 0.40)
Admission GCS score
GCS 15	385	83.5	490	91.1	0.001	0.46 (0.43 to 0.49)
GCS 14	51	11.1	33	6.1
GCS 13	25	5.4	15	2.8
Skull fracture	96	20.8	2	0.4	<0.001	0.60 (0.57 to 0.63)
Basilar skull fracture	10	2.2	0	0	<0.001	0.51 (0.48 to 0.54)
GCS score drop ≥2 points	20	4.3	8	1.5	0.007	0.51 (0.48 to 0.55)
Penetrating skull injury	3	0.7	0	0	0.098	0.50 (0.47 to 0.53)
Vomiting ≥2 times	40	8.7	47	8.7	0.999	0.50 (0.47 to 0.53)
Neurological deficit	57	12.4	29	5.4	<0.001	0.53 (0.50 to 0.57)
Post-traumatic seizure	17	3.7	14	2.6	0.363	0.51 (0.47 to 0.54)
Headache	164	35.6	131	24.4	<0.001	0.56 (0.53 to 0.59)
Severe headache	33	7.2	0	0	<0.001	0.53 (0.50 to 0.57)
Post-traumatic amnesia	262	58.8	131	24.4	<0.001	0.66 (0.63 to 0.69)
History of LOCs	312	67.7	87	16.2	<0.001	0.76 (0.73 to 0.78)
Scalp/facial hematoma	85	18.4	41	7.6	<0.001	0.55 (0.52 to 0.59)
Intoxication	89	25.9	35	22.6	0.502	0.52 (0.47 to 0.56)

AuROC, area under receiving operating characteristic curve; GCS, Glasgow Coma Scale; LOC, loss of consciousness; TBI, traumatic brain injury.