Abstract
BACKGROUND: The association between serum uric acid (UA) and all-cause and cardiovascular-related mortality in hemodialysis (HD) patients is conflicting. We investigated this association and explored the effect modification of underlying nutritional status, as reflected in the lean tissue index (LTI) and the Geriatric Nutritional Risk Index (GNRI), which serve as markers of muscle mass and nutritional risk in HD patients. METHODS: A retrospective cohort study was conducted from January 2019 to December 2023. We investigated the association between serum UA and the outcomes using the Cox proportional hazards regression and restricted cubic splines. Subgroup analyses based on the LTI and GNRI were conducted to explore possible effect modification. RESULTS: During a mean follow-up of 32.9 months, 876 patients who underwent HD were included in the analysis. The association between serum UA and all-cause mortality showed a non-linear U-shaped pattern (p = 0.007), with a survival benefit observed for the patients with serum UA levels between 3.4 and 6.8 mg/dL. In the multivariable-adjusted model, the low and high UA groups were associated with a greater risk of all-cause mortality compared to the reference UA group (hazard ratio (HR) =1.24, confidence interval (CI) 1.03-2.12, p = 0.027; HR = 1.09; CI 1.05-2.08. p = 0.012). In the low UA group, a greater risk of mortality was observed in patients with low LTI (<12.3; HR 1.56, 95% CI 1.22-1.82) and GNRI values (<102.1; HR 1.43, 95% CI 1.12-1.76), but not in those with high LTI and GNRI values. There was no significant association between serum UA and cardiovascular disease-related mortality. CONCLUSION: Our study showed that lower and higher serum UA levels increase the risk of all-cause mortality in HD patients. Among the patients with lower UA levels, low LTI and GNRI values showed a greater risk of mortality. This finding suggested that better nutritional status, rather than elevated UA levels, is likely to improve long-term survival in HD patients.