Traumatic Brain Injury and Substance Related Disorder: A 10-Year Nationwide Cohort Study in Taiwan

Table 2

Incidence and hazard ratios of substance related disorder by demographic characteristics and comorbidity among patients with or without TBI.

Variables	Patients with TBI		Patients without TBI		Compared to non-TBI		for interaction
	Substance related disorder	Rate	Substance related disorder	Rate	Crude HR (95% CI)	Adjusted HR (95% CI)
Overall	340	1.97	118	0.41	5.71 (4.58–7.12)	3.62 (2.87–4.57)
Gender
Men	265	2.69	94	0.57	5.64 (4.40–7.23)	3.69 (2.84–4.79)
Women	75	1.01	24	0.19	5.88 (3.64–9.49)	3.45 (2.06–5.78)
Stratify by age
18–39	256	2.79	65	0.45	7.20 (5.44–9.53)	5.03 (3.76–6.72)	<0.001
≥40	84	1.04	53	0.37	3.39 (2.39–4.81)	1.91 (1.33–2.75)
Comorbidity
No	122	1.68	54	0.31	6.51 (4.69–9.04)	5.14 (3.69–7.16)	0.002
Yes	218	2.17	64	0.57	4.55 (3.42–6.06)	2.59 (1.93–3.49)

Rate, incidence rate per 1000 person-years; 95% CI, 95% confidence interval; HR, hazard ratio; TBI, traumatic brain injury.
Model adjusted for age, gender, income, urbanization level, Charlson Comorbidity Index, and relevant comorbidities (hypertension, diabetes mellitus, hyperlipidemia, coronary artery disease, congestive heart failure, chronic obstructive pulmonary disease, and malignancy).
Patients with any examined comorbidities, including hypertension, diabetes mellitus, hyperlipidemia, coronary artery disease, congestive heart failure, chronic obstructive pulmonary disease, and malignancy, were classified as the comorbidity group.
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