Objectives: Serum uric acid (SUA) is associated with poor outcomes in patients with numerous types of disease. However, the association between SUA and the outcomes of patients with rheumatoid arthritis (RA) remains to be fully elucidated. Thus, the present study aimed to determine the associations between SUA and all-cause or cardiovascular disease (CVD)-associated mortality in adults with RA.
Methods: The data of patients with RA were collected from the National Health and Nutrition Examination Survey from 2001 to 2018. All-cause and CVD-associated mortality were identified using national death records through 31 December 2019. Weighted survival curves, Cox proportional hazards regression models, restricted cubic splines (RCS) and stratified analyses were used to assess the association between SUA levels and mortality.
Results: Among 2,312 patients with RA, a total of 597 all-cause deaths and 198 CVD-associated deaths were recorded during 19,133 person-years of follow-up. The results of the Kaplan-Meier curves for long-term all-cause and CVD-associated mortality demonstrated that increased levels of SUA were associated with a higher incidence of mortality. In the fully adjusted models, the highest SUA quartile exhibited hazard ratios [(HRs); 95% confidence intervals (CIs)] of 1.53 (1.10, 2.14) for all-cause mortality and 1.93 (1.14, 3.27) for CVD-associated mortality, compared with the lowest SUA quartile. The results of the RCS analysis confirmed a strong linear association between SUA levels and the HR of all-cause mortality, while a U-shaped association was observed between SUA and CVD-associated mortality.
Conclusions: The results of the present study demonstrated that high SUA levels were significantly associated with increased risks of all-cause and CVD-associated mortality in patients with RA. Further studies are required to elucidate the potential impact of treatments on reducing SUA levels.