Table 2

Factors of injury and subgroup of injury by using Cox regression

Injury severity	With dementia			Without dementia			With versus Without
Injury severity	Event	PYs	Rate (per 10⁵ PYs)	Event	PYs	Rate (per 10⁵ PYs)	Adjusted HR	95% CI	P
Total	6701	49 964.72	13 411.46	20 919	374 918.24	5579.62	2.294	2.229 to 2.361	<0.001
Outpatient	4986	49 964.72	9979.04	17 041	374 918.24	4545.26	2.302	2.227 to 2.380	<0.001
Inpatient	983	49 964.72	1967.39	1667	374 918.24	444.63	2.373	2.179 to 2.583	<0.001
ISS ≥16	782	49 964.72	1565.10	2211	374 918.24	589.73	2.091	19.15 to 2.283	<0.001
Sex
Male	3634	26 700.46	13 610.25	10 724	205 214.96	5225.74	2.399	2.306 to 2.496	<0.001
Female	3067	23 264.26	13 183.31	10 195	169 703.28	6007.54	2.171	2.082 to 2.264	<0.001
Age groups (years)
50–64	132	740.08	17 835.91	315	4655.96	6765.52	2.411	1.937 to 3.000	<0.001
≥65	6569	49 224.64	13 344.94	20 604	370 262.28	5564.70	2.292	2.226 to 2.359	<0.001

Adjusted HR, adjusted for sex, age, comorbidity, urbanization, geography, and income; ISS, Injury Severity Score; PYs, person years.