Creatinine-to-body weight ratio as an independent predictor of hepatic steatosis severity in metabolic dysfunction-associated steatotic liver disease: a cross-sectional study

Metabolic dysfunction-associated steatotic liver disease (MASLD) is closely tied to systemic metabolic dysregulation, yet reliable biomarkers of steatosis severity remain limited. The creatinine-to-body weight (Cr/BW) ratio, a surrogate for muscle mass and renal function, has been proposed as a predictor of MASLD; however, its correlation with hepatic steatosis severity, quantified by the controlled attenuation parameter (CAP), remains poorly defined. In this cross-sectional study of 1,492 participants (946 MASLD; 546 non-MASLD), we evaluated the association between the Cr/BW ratio and CAP-measured steatosis severity (mild, moderate, or severe) using ordinal logistic regression. Nonlinear relationships were explored using restricted cubic splines (RCS), and predictive performance was assessed using the area under the receiver operating characteristic curve (AUROC). To ensure robustness, subgroup analyses were conducted by age and sex. Severe MASLD (CAP ≥ 295 dB/m) was associated with a significantly lower Cr/BW ratio (median 0.89 vs. 1.03 in mild steatosis; P < 0.001). The Cr/BW ratio independently predicted steatosis severity (adjusted OR per 0.1-unit decrease: 0.03; 95% CI: 0.02–0.05; P < 0.001). RCS analysis revealed a threshold effect, and the risk of severe steatosis rose sharply below a Cr/BW ratio of 1.01 (OR = 0.02; 95% CI: 0.01–0.05). The AUROC for the Cr/BW ratio was 0.72, outperforming traditional metabolic markers. The findings were also consistent across age and sex subgroups. The Cr/BW ratio is inversely and independently associated with the severity of hepatic steatosis in MASLD. A threshold of 1.01 may serve as a marker to identify high-risk patients, supporting its integration into clinical screening and management strategies.