Midlife Ankylosing Spondylitis Increases the Risk of Cardiovascular Diseases in Males 5 Years Later: A National Population-Based Study

There are limited studies describing the association between ankylosing spondylitis (AS) and cardiovascular disease (CVD) in patients over 40 years old. We aimed to focus on the incident AS patients in those aged 40 years or older and to investigate whether events of CVD occurred more than the general population. We conducted a nationwide cohort study between 2000 and 2005 using the Taiwan National Health Insurance Research Database. The risk of newly diagnosed CVD was compared between incident AS patients and matched age- and sex-matched subjects without AS. Events of CVDs were classified into 1 of 5 subcategories: hypertensive heart disease, coronary heart disease, congestive heart failure, cerebrovascular disease, or “other” CVD according to the ICD-9-CM codes. Cumulative incidences and hazard ratios (HRs) were calculated after adjusting for demographic and comorbid medical disorders. Multivariate analyses were performed using Cox proportional hazards model. We compared 537 AS and 2685 non-AS patients and found that the cumulative incidence rate of CVD during follow-up period was higher in the AS cohort than the non-AS cohort. The crude HR of CVD for the AS group was 1.24 [95% confidence interval (95% CI), 1.05–1.46; P = 0.01] and the adjusted HR was 1.20 with 95% CI 1.02 to 1.42 (P = 0.03). When stratified by age, AS cohort at age 60 to 69 years exhibited a significantly higher HR for all CVD than the general population cohort (adjusted HR 1.48, 95% CI 1.06–2.08, P < 0.05). When stratified by gender, male AS group had a significantly higher HR for all CVD than the general population cohort with the adjusted HR 1.28 (95% CI 1.01–1.63, P < 0.05). There was no statistically significant difference for females. Patients with AS, especially age 60 to 69 years male patients, had a higher risk of CVDs than non-AS controls.