Increased Risk of Ischemic Heart Disease in Young Patients with Newly Diagnosed Ankylosing Spondylitis - A Population-Based Longitudinal Follow-Up Study

Background: Prospective data is sparse on the association between ischemic heart disease (IHD) and ankylosing spondylitis (AS) in the young. The purpose of this population-based, age- and sex-matched follow-up study was to investigate the risk of IHD in young patients with newly diagnosed AS. Methods: A total of 4794 persons aged 18 to 45 years with at least two ambulatory visits in 2001 with the principal diagnosis of AS were enrolled in the AS group. The non-AS group consisted of 23970 age-and sex-matched, randomly sampled subjects without AS. The three-year IHD-free survival rate and cumulative incidence of IHD were calculated using the Kaplan-Meier method. The Cox proportional hazards regression model was used to estimate the hazard ratio of IHD after controlling for demographic and cardiovascular co-morbidities. Results: During follow-up, 70 patients in the AS group and 253 subjects in the non-AS group developed IHD. The cumulative incidence rate of IHD over time was higher in the AS group than the non-AS group. The crude hazard ratio of IHD for the AS group was 1.47 (95% CI, 1.13 to 1.92; p = 0.0043) and the adjusted hazard ratio after controlling for demographic characteristics and comorbid medical disorders was 1.47 (95% CI, 1.13 to 1.92; p = 0.0045). Conclusions: This study showed an increased risk of developing IHD in young patients with newly diagnosed AS.