J Head Trauma Rehabil Vol. 29, No. 6, pp. 514–521 Copyright c  2014 Wolters Kluwer Health | Lippincott Williams & Wilkins Risk and Mortality of Traumatic Brain Injury in Stroke Patients: Two Nationwide Cohort Studies Yi-Chun Chou, MD; Chun-Chieh Yeh, MD; Chaur-Jong Hu, MD; Nai-Hsin Meng, MD; Wen-Ta Chiu, MD, PhD; Wan-Hsin Chou, MPH; Ta-Liang Chen, MD, PhD; Chien-Chang Liao, PhD, MPH Objective: Patients with stroke had higher incidence of falls and hip fractures. However, the risk of traumatic brain injury (TBI) and post-TBI mortality in patients with stroke was not well defined. Our study is to investigate the risk of TBI and post-TBI mortality in patients with stroke. Methods: Using reimbursement claims from Taiwan’s National Health Insurance Research Database, we conducted a retrospective cohort study of 7622 patients with stroke and 30 488 participants without stroke aged 20 years and older as reference group. Data were collected on newly developed TBI after stroke with 5 to 8 years’ follow-up during 2000 to 2008. Another nested cohort study including 7034 hospitalized patients with TBI was also conducted to analyze the contribution of stroke to post-TBI in-hospital mortality. Results: Compared with the nonstroke cohort, the adjusted hazard ratio of TBI risk among patients with stroke was 2.80 (95% confidence interval = 2.58-3.04) during the follow-up period. Patients with stroke had higher mortality after TBI than those without stroke (10.2% vs 3.2%, P < .0001) with an adjusted relative risk (RR) of 1.46 (95% confidence interval = 1.15-1.84). Recurrent stroke (RR = 1.60), hemorrhagic stroke (RR = 1.68), high medical expenditure for stroke (RR = 1.80), epilepsy (RR = 1.79), neurosurgery (RR = 1.94), and hip fracture (RR = 2.11) were all associated with significantly higher post-TBI mortality among patients with stroke. Conclusions: Patients with stroke have an increased risk of TBI and in-hospital mortality after TBI. Various characteristics of stroke severity were all associated with higher post-TBI mortality. Special attention is needed to prevent TBI among these populations. Key words: mortality, stroke, traumatic brain injury S TROKE REMAINS the second leading cause of death and the leading cause of acquired disabil- ity in adults in most regions. 1,2 In the United King- dom, productivity loss arising from stroke was estimated to result in total societal costs of 8.9 billion pounds Author Affiliations: Department of Physical Medicine and Rehabilitation, China Medical University Hospital, Taichung, Taiwan (Drs Chou and Meng); School of Medicine, China Medical University, Taichung, Taiwan (Dr Yeh); Department of Neurology, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan (Dr Hu); Graduate Institute of Injury Prevention and Control, Taipei Medical University, Taipei, Taiwan (Dr Chiu); Department of Anesthesiology, Taipei Medical University Hospital, Taipei, Taiwan (Ms Chou, Drs Chen, and Liao); Health Policy Research Center, Taipei Medical University Hospital, Taipei, Taiwan (Drs Chen and Liao); School of Medicine, Taipei Medical University, Taipei, Taiwan (Drs Hu, Chen, and Liao). This study is based in part on data obtained from the National Health Insur- ance Research Database provided by the Bureau of National Health Insurance, Department of Health and managed by the National Health Research Insti- tutes. The interpretation and conclusions contained herein do not represent those of the Bureau of National Health Insurance, Department of Health, or National Health Research Institutes. This research was supported by a Foundation for Anesthesia Education and Research fellowship grant to Taipei Medical University. This study is also supported in part by National Science Council (NSC102-2314-B-038-021- MY3) and Taiwan Department of Health Clinical Trial and Research Center of Excellence (DOH102-TD-B-111-004). sterling per year. 3 The increasing incidence of stroke in younger people prolongs the disabled period and causes higher societal burden. 4 Complications after stroke in- clude falls, pneumonia, urinary tract infection, epilepsy, mental disorders, dysphagia, pressure ulcer, and con- stipation; these sequelae may worsen stroke survivors’ medical conditions. 5,6 Other complications associated with stroke are still being researched. Traumatic brain injury (TBI) is among the most seri- ous forms of trauma, 7 it causes an estimated 1.7 million patients annually, including 1.365 million emergency care visits, 275 000 hospitalizations, and 52 000 deaths in the United States. 8 Socioeconomic impacts of disabil- ity following TBI are potentially long-term or lifelong, 7,9 and TBI remains a worldwide leading cause of disability and death. 10–12 Yi-Chun Chou and Ta-Liang Chen contributed equally to the article. The authors declare no conflicts of interest. Corresponding Author: Chien-Chang Liao, PhD, MPH, Department of Anesthesiology, Taipei Medical University Hospital, 252 Wuxing St, Taipei 110, Taiwan (jacky48863027@yahoo.com.tw; ccliao@tmu.edu.tw). DOI: 10.1097/HTR.0000000000000007 Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 514