Abstract: Objective The purpose of this study was to explore the clinical value of fasting C-peptide in assessing the progression of liver fibrosis in patients with non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM). Methods 456 patients with NAFLD and T2DM were recruited in this study, and all of them underwent liver stiffness measurement (LSM), which showed that 41 patients had progressive hepatic fibrosis (PHF, LSM >7.9 kPa) and 415 hadn’t (Nphf, LSM ＜7.9 kPa). The Logistic regression analysis was applied to explore the risk factors of liver fibrosis progression, and the receiver operating characteristic curve(ROC) was used to evaluate the diagnostic value of fasting C-peptide for progressive liver fibrosis in this setting. Results The blood HDL-C, PLT counts, serum AST, fasting C-peptide and HbA1c levels in patients with PHF were (1.5±0.2)mmol/L, (259.3±50.3)×10⁹/L, (39.3±5.1)U/L, (2.7±0.8)ng/ml and (10.7±1.0)%, significantly different as compared to 【(1.4±0.3)mmol/L, (267.1±48.2)×10⁹/L, (26.1±4.1)U/L,(2.1±0.7)ng/ml and (8.1±1.1)%, respectively, P<0.05】 in patients with nPHF; non-conditional univariate analysis and multivariate analysis showed that the age , gender (OR=1.250, 95% CI:1.005-1.554, P=0.045), BMI (OR=1.117, 95% CI:1.011-1.235, P=0.030), HbA1c level (OR=1.117, 95% CI:1.011-1.235, P=0.030) and fasting C-peptide (OR=1.206, 95% CI:1.068-1.361, P=0.003) were the risk factors, and the ROC analysis demonstrated that the area under ROC (AUC) for fasting C peptide was 0.7 (95% CI:0.7-0.81, P<0.05), e.g. when serum fasting C-peptide level equal to 2.36 ng/mL as the cut-off-value, the sensitivity was 73.2% and the specificity was 67.0%. Conclusion The application of fasting C-peptide in the diagnosis of PHF in patients with NAFLD and T2DM is valuable, which warrants further investigation.

Key words: Nonalcoholic fatty liver disease, Type 2 diabetes mellitus, Liver fibrosis, Fasting C-peptide, Logistic analysis, Diagnosis