Abstract: Objective To investigate the correlation between the serum uric acid/creatinine (sUA/Cr) ratio and metabolic-associated fatty liver disease (MAFLD) in non-obese patients. Methods A retrospective analysis was conducted on individuals who underwent annual physical examinations at the Health Management Center of the First Affiliated Hospital of the Naval Medical University from July to December 2023. The study subjects were divided into three groups: non-obese MAFLD patients (n=669), obese MAFLD patients (n=1594), and non-obese healthy controls (n=116). Ggeneral conditions, baseline liver and kidney functions, blood glucose levels, and lipid profiles, and sUA/Cr levels were compared between the groups. Binary logistic regression was employed to analyze the risk factors for non-obese MAFLD, while ROC curves were used to evaluate the predictive efficacy of sUA/Cr, BMI, ALT, and TG for non-obese MAFLD. Spearman’s test was utilized for correlation analysis. Results Among 8764 individuals undergoing physical examinations, 26.8% were diagnosed with MAFLD, with the non-obese type accounting for 29.6% of all MAFLD cases. Compared to non-obese healthy controls, non-obese MAFLD patients were older, had a higher proportion of males, and sxhibited elevated levels of ALT, AST, γ-GT, AKP, FBG, TG, TC, LDL-C, sUA[345.0(289.0,399.0) vs. 262.0(230.3,306.5)μmol/L], Cr[73.0(61.0,83.3) vs. 60.0(53.0,68.0)μmol/L], and sUA/Cr ratio[4.8(4.1,5.5) vs. 4.3(3.9,4.9)], while HDL-C was lower. These differences were statistically significant (P< 0.05). Binary logistic regression analysis indicated that older age, male gender, BMI, ALT, and TG were independent risk factors for MAFLD in the non-obese population (P< 0.05), while sUA/Cr was not an independent risk factor (P>0.05). ROC curves analysis demonstrated that sUA/Cr (AUC=0.6399, 95%CI 0.5821-0.6857), BMI (AUC=0.8198, 95%CI 0.7715-0.8681), ALT (AUC=0.7868, 95%CI 0.7408-0.8328), and TG (AUC=0.8208, 95%CI 0.7802-0.8613) could predict MAFLD occurrence in non-obese individuals sUA/Cr was not correlated with BMI (r=0.05, P<0.01), ALT (r=0.04, P<0.01) or TG (r=0.02, P<0.01). Using an optimal cut-off value of 4.365 for sUA/Cr, the non-obese population was divided into low and high sUA/Cr groups, with MAFLD incidences of 78.0% and 89.5%, respectively, showing a statistically significant difference (χ²=19.120, P<0.01). Conclusion The sUA/Cr ratio is associated with the occurrence of non-obese MAFLD and can be used to predict the development of non-obese MAFLD by monitoring sUA/Cr levels.

Key words: Uric acid, Creatinine, Metabolism-associated fatty liver disease, Non-obese type