Serum uric acid and mortality in metabolic dysfunction-associated steatotic liver disease: Subgroup differences.

Background And Aims: This study aims to investigate the association between serum uric acid (SUA) and both the risk and long-term mortality of dysfunction-associated steatotic liver disease (MASLD), and to explore differences between the pure MASLD and metabolic and alcohol related/associated liver disease (MetALD) subgroups.

Methods And Results: We included 11,675 participants from the Third National Health and Nutrition Examination Survey, with matched mortality data up to 2019. Logistic regression and Cox proportional hazards regression evaluated the relationship between SUA and both the risk and mortality of MASLD. Non-linear correlations and threshold effects were explored using restricted cubic splines and a two-piecewise Cox proportional hazards model. We found that SUA was positively associated with the risk of MASLD [odds ratio (OR): 1.19, 95 % confidence interval (CI) 1.12-1.27]. For pure MASLD, SUA showed a positive association with all-cause mortality [<4.7 mg/dL: hazard ratio (HR): 1.34, 95 % CI 1.04-1.73; ≥4.7 mg/dL: HR: 1.08, 95 % CI 1.02-1.15] and cardiovascular mortality (HR: 1.12, 95 % CI 1.02-1.22). For MetALD, there was an inverse J-shaped relationship (threshold: 6.6 mg/dL) between SUA and all-cause mortality. Below the threshold, SUA was negatively correlated with all-cause mortality (HR: 0.42, 95 % CI 0.19-0.93), but no association was found above it (HR: 0.81, 95 % CI 0.54-1.21). Additionally, no association was observed between SUA and cardiovascular mortality.

Conclusions: SUA serves as an independent predictor of the risk and all-cause mortality of MASLD. The relationship between SUA and both all-cause and cardiovascular mortality differs between the pure MASLD and MetALD subgroups.