Abstract: Background Type 2 diabetes mellitus（T2DM） is the most common type of diabetes. The incidence of metabolic associated fatty liver disease（MAFLD） in T2DM patients is higher than that in non - diabetic patients. Therefore，it is of great significance to find effective indicators for predicting the occurrence of MAFLD in T2DM patients. Objective This study aims to explore the predictive value of the ratio of fasting C-peptide to diabetes duration（FCP/DD） for the occurrence of MAFLD in patients with Type 2 Diabetes Mellitus（T2DM），providing a potential indicator for the early prevention and management of MAFLD. Methods This study enrolled 532 patients diagnosed with Type 2 Diabetes Mellitus（T2DM） at the Department of Endocrinology，Hebei General Hospital，between September 2018 and December 2021. Demographic data were collected，and fasting blood samples were obtained to assess biochemical parameters. The fasting C-peptide to diabetes duration（FCP/DD） ratio was computed using a predefined formula. Participants were stratified into MAFLD（n=359）and non MAFLD（n=173） groups based on the presence or absence of Metabolic Associated Fatty Liver Disease（MAFLD）. Further classification into low FCP/DD（n=266） and high FCP/DD（n=266） groups was performed according to the median FCP/DD ratio. The relationship between the FCP/DD ratio and MAFLD incidence in T2DM patients was examined using Spearman rank correlation and logistic regression analyses. The predictive efficacy of the FCP/DD ratio for MAFLD was evaluated by constructing receiver operating characteristic（ROC） curves and calculating the area under the curve（AUC）. Results The FCP/DD in the MAFLD group was higher than that in the non-MAFLD group（P<0.05）. The incidence of MAFLD in the high FCP/DD group was higher than that in the low FCP/DD group（P<0.05）. The Spearman rank correlation analysis results showed that in patients with T2DM and MAFLD，FCP/DD was negatively correlated with age and high-density lipoprotein cholesterol（HDL-C），and positively correlated with BMI，fasting blood glucose（FBG），glycated hemoglobin（HbA1c），total cholesterol（TC），triglycerides（TG），low-density lipoprotein cholesterol（LDL-C），serum uric acid（SUA），aspartate aminotransferase（AST），alanine aminotransferase（ALT），and triglyceride-glucose index（TyG）（P<0.05）. The results of multivariate Logistic regression analysis showed that after adjusting for confounding factors，a high level of FCP/DD was an independent risk factor for the occurrence of MAFLD in T2DM patients（P<0.05）. The ROC curve results showed that the AUC of FCP/DD for predicting the occurrence of MAFLD in T2DM patients was 0.829（0.791-0.867），the AUC of FCP was 0.758（95%CI=0.711-0.805），the AUC of HbA1c was 0.525（0.471-0.578），and the AUC of TyG was 0.733（95%CI=0.689-0.778）.Conclusion The level of FCP/DD was significantly increased. T2DM patients with high levels of FCP/DD had a higher risk of developing MAFLD. FCP/DD ratio has better predictive value than FCP，HbA1c，TyG for combined MAFLD in T2DM patients.

Key words: Type 2 diabetes mellitus, Metabolism-associated fatty liver disease, Fasting C-peptide, Diabetes duration, Insulin resistance, Triglyceride glucose index

摘要： 背景 2型糖尿病（T2DM）是糖尿病中最常见的类型，T2DM患者代谢相关脂肪性肝病（MAFLD）发病率较非糖尿病患者高，因此寻找有效预测T2DM患者发生MAFLD的指标意义重大。目的 探讨空腹C肽与糖尿病病程比值（FCP/DD）预测T2DM患者发生MAFLD的预测价值，为早期防治MAFLD提供预测指标。方法 选取2018年9月—2021年12月河北省人民医院内分泌科收治的T2DM患者532例，收集患者的一般资料，并抽取空腹血液检测生化指标，按照公式计算FCP/DD。按照T2DM患者是否发生MAFLD，将患者分为MAFLD组（n=359）和无MAFLD组（n=173）；根据FCP/DD比值的中位数，将研究对象分为低FCP/DD组（n=266）和高FCP/DD组（n=266）。采用Spearman秩相关及Logistic回归分析探讨FCP/DD比值与T2DM患者发生MAFLD的相关性，并建立受试者工作特征（ROC）曲线及计算曲线下面积（AUC），探讨FCP/DD比值预测T2DM患者发生MAFLD的价值。结果 MAFLD组FCP/DD高于无MAFLD组（P<0.05）。高FCP/DD组MAFLD发生率高于低FCP/DD组（P<0.05）。Spearman秩相关分析结果显示，T2DM合并MAFLD患者FCP/DD与年龄、高密度脂蛋白胆固醇（HDL-C）呈负相关，与BMI、空腹血糖（FBG）、糖化血红蛋白（HbA1c）、总胆固醇（TC）、三酰甘油（TG）、低密度脂蛋白胆固醇（LDL-C）、血尿酸（SUA）、天冬氨酸氨基转移酶（AST）、丙氨酸氨基转移酶（ALT）、三酰甘油葡萄糖指数（TyG）呈正相关（P<0.05）。多因素Logistic回归分析结果显示，在校正混杂因素后，高水平FCP/DD是T2DM患者发生MAFLD的独立危险因素（P<0.05）。ROC曲线结果显示，FCP/DD预测T2DM患者发生MAFLD的AUC为0.829（0.791~0.867），FCP的AUC为0.758（95%CI=0.711~0.805），HbA1c的AUC为0.525（0.471~0.578），TyG的AUC为0.733（95%CI=0.689~0.778）。结论 T2DM合并MAFLD组FCP/DD水平升高。高水平FCP/DD的T2DM患者发生MAFLD的风险更高。FCP/DD较FCP、HbA1c、TyG对T2DM患者合并MAFLD有更好的预测价值。

关键词: 2 型糖尿病, 代谢相关脂肪性肝病, 空腹 C 肽, 糖尿病病程, 胰岛素抵抗, 三酰甘油葡萄糖指数