Prevalence and influence of hypouricemia on cardiovascular diseases in patients with rheumatoid arthritis

Abstract

Abstract Background Serum uric acid (SUA) acts as an antioxidant and abnormally low SUA may raise the risk of developing atherosclerotic disorders. There is a U-shaped association between SUA with cardiovascular diseases (CVDs) in general population. However, the prevalence of hypouricemia and its influence on CVDs in rheumatoid arthritis (RA) remains unclear. Methods This cross-sectional study collected clinical data from a Chinese RA cohort. Hypouricemia was defined as SUA ≤ 3.0 mg/dL, and hyperuricemia was defined as SUA ≥ 7.0 mg/dL. CVDs were defined as a history of angina pectoris, myocardial infarction, heart failure, stroke and peripheral arterial disease. Restricted cubic spline regression and logistic regression analysis were conducted to evaluate the associations between SUA levels and CVDs. Results Among 1130 RA patients recruited, the mean age was 53.2 years and 79.0% were female. The prevalence of hypouricemia and hyperuricemia were 10.6% and 12.0%, respectively. RA patients with hyperuricemia had a higher rate of CVDs than normouricemic patients (27.9% vs. 7.1%, P < 0.05). Surprisingly, RA patients with hypouricemia also had a higher rate of CVDs (20.7% vs. 7.1%, P < 0.05) even without higher traditional cardiovascular risk factors. A U-shaped association between SUA levels and total CVDs was found (Pnon-linear < 0.001). Multivariate logistic regression analysis revealed that compared with normouricemia, both hypouricemia [adjusted OR (AOR) = 4.707, 95% CI 2.570–8.620] and hyperuricemia (AOR = 3.707, 95% CI 2.174–6.321) were associated with higher risk of CVDs. Conclusions Hypouricemia may be a potential risk factor of CVDs in RA patients