The CRP-to-Uric Acid Index (CURI): A Novel Inflammatory–Metabolic Index to Enhance Noninvasive Screening for MASLD and Liver Fibrosis

Abstract Background Metabolic dysfunction-associated steatotic liver disease (MASLD) and significant liver fibrosis (SLF) require noninvasive screening. This study evaluates the C-reactive protein-to-uric acid index (CURI), combining inflammation and metabolic dysfunction, as a biomarker for early detection of MASLD and SLF. Methods Using NHANES 2017–2020 data (n=6,687), participants were divided into training and validation cohorts. CURI was calculated as high-sensitivity C-reactive protein (hs-CRP; mg/L) × [uric acid (mg/dL)]3. Associations with MASLD and SLF were analyzed via logistic regression, restricted cubic splines, and mediation analysis considering insulin resistance and adipose indices. Diagnostic performance was evaluated using the area under the curve (AUC), decision curve analysis (DCA), comparing CURI with established indices: fatty liver index (FLI), hepatic steatosis index (HSI), and fibrosis-4 (FIB-4). Results MASLD and SLF prevalence were 49.6% and 10.7%, respectively. CURI was independently associated with MASLD and SLF. Nonlinear relationships were observed. Combining CURI with FLI, HSI, or FIB-4 improved diagnostic performance compared to using them alone (AUC for MASLD: 0.852 with FLI, 0.819 with HSI, 0.690 with FIB-4; AUC for SLF: 0.811 with FLI, 0.750 with HSI, 0.699 with FIB-4, p<0.001). DCA showed net benefit for MASLD. Mediation analysis show 98.1% (MASLD) and 84.8% (SLF) of effects. Conclusion CURI is a promising, cost-effective biomarker for MASLD/SLF risk stratification. Highlights WHAT IS KNOWN MASLD and SLF require noninvasive screening. Existing methods like liver biopsy are invasive. Indices like FLI, HSI, and FIB-4 are commonly used for screening. WHAT IS NEW HERE CURI is a novel biomarker combining inflammation and metabolic dysfunction for screening. CURI is independently associated with MASLD and SLF. CURI enhances prediction when combined with FLI or HSI. Insulin resistance mediates most of CURI effect on MASLD and SLF. CURI is a cost-effective tool for risk stratification in resource-limited settings.