A nationwide population-based retrospective cohort study: increased risk of acute coronary syndrome in patients with ankylosing spondylitis

OBJECTIVES: To compare the risk of acute coronary syndrome (ACS) between patients with and without ankylosing spondylitis (AS). METHOD: This retrospective cohort study identified all patients with AS aged ≥ 18 years newly diagnosed from 2000 to 2009, registered in the National Health Insurance Research Database (NHIRD) in Taiwan. The non-AS cohort consisted of fourfold randomly selected control patients free of AS, frequency matched by age, sex, and diagnosis year. The incidence of ACS was determined for both AS and non-AS cohorts. RESULTS: We selected 6262 patients with AS and 25 048 patients without AS. The patients with AS were more prevalent than those without, with co-morbidities of hypertension, diabetes mellitus (DM), hyperlipidaemia, stroke, and peripheral vascular diseases. The overall incidence rate of ACS was higher in the AS cohort than in the non-AS cohort (4.4 vs. 2.9 per 1000 person-years), with an adjusted hazard ratio (aHR) of 1.36 [95% confidence interval (CI) 1.16-1.59]. AS patients with co-morbidities of hypertension, DM, and cancer had an aHR of 7.74 for ACS, compared to those without these co-morbidities. CONCLUSIONS: AS patients are at higher risk of ACS compared with non-AS subjects. Management of CV risk factors should be taken into account for the treatment of patients with AS, especially for patients with co-morbidities of hypertension, DM, and cancer.