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

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). 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. 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. Our nationwide longitudinal study suggests an increased risk of ischemic stroke in AS patients.