Association of ischemic stroke with ankylosing spondylitis: a nationwide longitudinal cohort study.

BACKGROUND: The purpose of this nationwide age- and sex-matched longitudinal follow-up study was to investigate the risk of developing ischemic stroke in ankylosing spondylitis (AS). METHODS: The data in this study, spanning from January 1, 2010 to December 31, 2014, was obtained from a database maintained by the Korean National Health Insurance Service. A total of 12,988 patients with a diagnosis of AS were enrolled. The control group consisted of 64,940 age-sex-stratified matching subjects without AS. The 6year ischemic stroke incidence rate for each group was calculated using the Kaplan-Meier method. Cox proportional hazards regression analysis was used to estimate the hazard ratio of ischemic stroke. RESULTS: During the follow-up period, 73 patients (0.56%) in the AS group and 250 patients (0.38%) in the control group developed ischemic stroke (p = 0.0041). The hazard ratio of ischemic stroke in the AS group was 1.46 (95% confidence interval [95% CI], 1.13-1.90) after adjusting for age and sex. The adjusted hazard ratio of ischemic stroke in the AS group was 1.35 (95% CI, 1.04-1.75) after controlling for demographics and comorbid medical disorders. According to subgroup analysis, in female and diabetes and non-hypertension and dyslipidemia subgroups, ischemic stroke incidence rates were significantly higher in AS patients than those in control group. CONCLUSION: Our nationwide longitudinal study suggests an increased risk of ischemic stroke in AS patients.