Analysis of the Relationship between Adult Asthma and Stroke: A Longitudinal Follow-Up Study Using the Korean National Sample Cohort

Several previous studies demonstrated the risk of stroke in asthma patients. The aim of this study was to evaluate the risk of hemorrhagic and ischemic stroke in asthma patients, independent of age, sex, income, region of residence, and past medical histories. The Korean Health Insurance Review and Assessment Service-National Sample Cohort from 2002 through 2013 was used. Overall, 111,364 asthma patients ≥ 20 years old were matched to 111,364 control participants for age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia. Asthma was classified using ICD-10 codes (J45 and J46) and medication history. The admission histories were investigated for hemorrhagic stroke (I60-I62) and ischemic stroke (I63) using ICD-10 codes. The crude and adjusted (age, sex, income, region of residence, hypertension, diabetes, dyslipidemia, ischemic heart disease, and depression) hazard ratios (HRs) for hemorrhagic and ischemic stroke in asthma patients were analyzed using a Cox proportional hazards model. Subgroup analyses were conducted according to age and sex. Hemorrhagic and ischemic stroke were found in 0.7% (795/117,364) and 2.4% (922/117,364) of the asthma group and in 0.8% (922/117,364) and 2.6% (93,079/117,364) of the control group, respectively. The asthma group demonstrated adjusted HRs of 0.86 (95% confidence interval [CI] = 0.78-0.94, p = 0.002) for hemorrhagic stroke and 0.91 (95% CI = 0.86-0.95, p = 0.002) for ischemic stroke. None of the subgroups of asthma patients showed higher HRs for stroke. Asthma did not elevate the risk of either hemorrhagic or ischemic stroke.