Associations of stroke with all-cause and cause-specific mortality: A population-based matched cohort study

Background This study aimed to assess the specific associations between stroke and all-cause and cause-specific mortality among Korean adults. Methods We used data extracted from the Korean National Health Insurance claims database from 2002 to 2013, including information on individuals with or without stroke aged 20 years and older. Patients with intracerebral hemorrhage, ischemic stroke or unspecified stroke were classified as stroke patients, while a reference population matched in terms of sex and age were also selected. The outcomes were all-cause mortality, natural causes of death (i.e. all natural causes, death by stroke and death by other diseases) and suicide. Survival analysis was performed using the Cox proportional hazards model. Results Of the 73 150 eligible participants-including 14 630 stroke patients and 58 520 age- and sex-matched controls-11 121 (15.2%) died during the study period. Of them, 10 513 participants (94.5%) died of natural causes, including 1653 (14.5%) who died due to stroke and 8860 (79.7%) who died due to other diseases. Two hundred and fifty patients (2.2%) died by suicide. Stroke patients showed higher adjusted hazard ratios (HR) for all-cause (HR = 6.48, 95% CI, 3.87-10.86), all-natural-cause (HR = 2.68, 95% CI, 2.53-2.84), stroke (HR = 21.16, 95% CI, 17.49-25.61), other disease (HR = 1.69, 95% CI, 1.58-1.81) and suicide mortality (HR = 3.34, 95% CI, 2.24-4.98) than those without stroke. The effect size of stroke for suicide mortality was greater than that for other causes of mortality (except stroke mortality). Conclusions Stroke was associated with a higher risk of all-cause, natural cause and suicide mortality; stroke was more strongly associated with risk of suicide mortality than with any mortality for any other causes. From a policy standpoint, these results suggest the need for greater supportive care to prevent unnatural deaths among stroke patients.