Association of Parkinson's disease with ischemic stroke in Korea: A nationwide longitudinal cohort study in Korea.

OBJECTIVE: The aim of this nationwide age- and sex- matched longitudinal follow up study is to determine the risk of Parkinson's disease (PD) associated with ischemic stroke in Korea. METHODS: Patient data were collected from the National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS). PD was identified using the International Classification of Diseases (ICD) 10-CM code G 20. In total, 6,475 patients were enrolled in the PD group from the NHISS. After subtracting 1,039 patients who underwent hospitalization less than once or those who visited an outpatient clinic less than two times, 5,259 patients who were diagnosed after January 1, 2004 ultimately participated in this study. After case-control match was done through 1:5 age- and sex- stratified matching, 26,295 individuals were chosen as control. Kaplan-Meier method and Cox proportional hazard regression analysis were performed to evaluate the risk of ischemic stroke in PD. RESULTS: The hazard ratio of ischemic stroke in the PD group was 3.848 (95% confidence interval (confidence interval [CI]): 3.14-4.70) after adjusting for age and sex. The adjusted hazard ratio of ischemic stroke in PD group was 3.885 (95% CI: 3.17-4.75) after adjusting for comorbidities. According to subgroup analysis, in male and female and non-diabetes and diabetes and non-hypertension and hypertension and dyslipidemia and non-dyslipidemia subgroups, ischemic stroke incidence rates were significantly higher in the PD group than those in the control group. CONCLUSIONS: This nationwide longitudinal study suggests an increased risk of ischemic stroke in PD patients.