Increased risk of ischemic stroke in patients with burn injury: a nationwide cohort study in Taiwan
Hung et al. Scandinavian Journal of Trauma, Resuscitation
and Emergency Medicine
Increased risk of ischemic stroke in patients with burn injury: a nationwide cohort study in Taiwan
Tzu-Yao Hung 2
Yi-Kung Lee 0 1
Ming-Yuan Huang 4
Chen-Yang Hsu 3
Yung-Cheng Su 0 1
0 Emergency Department, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation , No. 2, Minsheng Rd., Dalin Township, Chiayi County 622 , Taiwan, R.O.C
1 School of Medicine, Tzu Chi University , Hualien , Taiwan
2 Emergency Department, Zhongxing Branch of Taipei City Hospital , Taipei , Taiwan
3 Department of Public Heath, National Taiwan University , Taipei , Taiwan
4 Department of Emergency Medicine, Mackay Memorial Hospital , Taipei , Taiwan
Background: Conflicting results have been obtained by studies attempting to assess the risks of ischemic stroke in patients with burn injury, while the long-term risk of stroke in survivors of burn injury remains unexplored. We evaluated whether the risk of ischemic stroke in patients hospitalized with burn injury in Taiwan is higher when compared to the general population. Methods: The data from one million National Health Insurance (NHI) adult beneficiaries were evaluated from January 1, 2005 until December 31, 2012 to identify those who developed ischemic stroke. Each identified patient with burn injury was matched with one hundred unexposed patients based on a high-dimensional propensity score. Cox regression models were applied to compare the risks of the development of ischemic stroke in the matched cohorts. Results: A total of 743,237 patients were enrolled. After matching, 1,763 burn injury patients and 176,300 unexposed patients were selected and compared. The adjusted hazard ratio of ischemic stroke was significantly increased in burn injury patients (1.84; 95 % CI, 1.43-2.36). A subgroup analysis based on patients who survived longer than 12 months in the matched cohort also revealed higher hazard ratio in the burn injury patients (1.54; 95 % CI, 1.11-2.13). Conclusion: The risk of ischemic stroke is significantly higher in patients hospitalized with burn injury than in the general population, and these risks may extend longer than expected.
Burns; Ischemic stroke; Cohort studies
Background
Stroke remains one of the leading causes of long-term
disability and mortality, with a worldwide incidence of
4.2–6.5 per 1000 person-years for people aged 55 or
older, resulting in a significant societal economic burden
[
1–3
]. Apart from patient management, early
identification of risk factors for the development of stroke is
critical to reduce morbidity and mortality. Several
precipitating co-morbidity factors have been reported to be
associated with stroke onset, including hypertension,
diabetes, hyperlipidemia, atrial fibrillation, and a history
of smoking [
4
]. Recently, the potential relationship
between burn injury and stroke has begun to receive
attention from the clinical community.
It is well known that cerebral complications are
common in victims of burn injury [
5, 6
]. Hypovolemia,
during the acute stage of burn injury, may induce poor
cerebral perfusion, resulting in ischemic stroke. In
addition, sepsis, a common complication in burn
patients, may represent another risk factor of stroke [7],
while a state of acquired hypercoagulopathy that is often
encountered following burn injury may present a further
risk of stroke in these patients [
8, 9
].
To our knowledge, few studies exist concerning the
incidence of ischemic stroke after burn injury, and the
results are contradictory [
6, 10
]. Moreover, the long-term
risk of stroke in survivors of burn injury remains
unexplored. In the present study, a large administrative
database was used to elucidate the risks of ischemic stroke
in burn injury patients in Taiwan. High-dimensional
propensity score (hdPS) matching (i.e., a semi-automated
statistical method) was used to address possible
confounding. The results of this study may help clinicians to
identify individuals at possible risk for stroke.
Methods
Ethics statement
This study was conducted in accordance to the tenets of
the Helsinki Declaration. The Institutional Review Board
of Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical
Foundation, Taiwan, approved the study. The need for
informed consent was waived because patient record/
information was anonymous and no identifiers were
employed.
Database
The Taiwanese National Health Insurance (NHI)
program was initiated in 1995, and has been described in
detail previously [
11–13
]. Utilizing the Longitudinal
Health Insurance Database (2005), a dataset comprising
1,000,000 individuals who were representative
beneficiaries of the NHI program was randomly sampled.
Study population
The representative population sample was systematically
tracked between January 1, 2003 and December 31,
2012. Individuals aged >18 years who were alive in 2005
were initially identified. Burn injury was defined by the
ICD-9-CM codes 940–949. Only pa (...truncated)