The increased risk of stroke in early insomnia following traumatic brain injury: a population-based cohort study.

OBJECTIVE: Insomnia, a common symptom after traumatic brain injury (TBI), may be a pre-symptom for developing stroke. This study aims to investigate whether insomnia is a potential risk factor for stroke after TBI, especially early insomnia.

METHODS: Taiwan's Longitudinal Health Insurance Database 2000 from 1999 to 2013 was used in this cohort study. TBI patients with insomnia were selected based on the ICD-9-CM code (TBI: 801-804 and 850-854; insomnia: 307.4, 327, and 780.5). The outcome we were interested in was stroke (ICD-9-CM: 430-438). The incidence rate ratio of stroke between TBI with insomnia and the general population with insomnia was calculated by Poisson regression. The relative risk adjusted for potential confounding variables was estimated by Cox regression.

RESULTS: For 1174 TBI patients with insomnia and 5870 general patients with insomnia, TBI patients have 209.85 incidence risk of new-onset stroke if they have insomnia. TBI patients have 2.28-fold (95% CI: 1.70-3.06) risk of new-onset stroke compared with the general population, even when controlling for age, gender, socioeconomic status, and comorbidities. The hazard ratio of new-onset stroke among different phases of new-onset insomnia after TBI surgery is 1.95-fold (95% CI: 1.05-3.62), 2.75-fold (95% CI: 1.73-4.37), and 2.66-fold (95% CI: 1.68-4.21) at ≤3, 3-12, and 12-24 months, compared with the general population with insomnia, respectively.

CONCLUSION: TBI patients with insomnia have a higher risk of stroke compared with the general population with insomnia. Early new-onset insomnias after TBI will have higher risk of stroke. Therefore, we consider that insomnia could be a signal of the development of new-onset stroke in TBI patients.