The coexistence of gout in ankylosing spondylitis patients: a case control study

Ankylosing spondylitis (AS) and gout are common inflammatory arthropathies. It had been claimed previously that the two conditions rarely coexist. The aim of this study was to compare the prevalence of gout in a population of AS patients to its prevalence in the general population. To conduct this population-based case-control study, data of adult patients with a physician diagnosis of AS were retrieved from the database of the largest health-care provider organization in Israel, Clalit Health Services. For each patient with AS, five age- and sex-matched subjects without AS were randomly selected from the same database. Different parameters including the existence of gout, hypertension, body mass index, socioeconomic status, and smoking were evaluated in both the AS and the control groups. The study included 3763 patients with AS and 19,214 controls. The proportion of gout in the AS group was higher than in the control group: 73 subjects in the AS group had gout, while only 107 subjects in the non-AS group had gout (1.94% and 0.56%, respectively, OR 3.53, P < 0.001). Logistic regression adjusting for possible confounding variables found that AS was independently associated with gout (OR 1.41, P = 0.037). Our study suggests that gout is not less common in AS patients in comparison with the general population, and that it might even be more common in AS patients.