Clinical Utility of Fasting Plasma Glucose and Hemoglobin A1C (HbA1C) for the Prediction of Type 2 Diabetes Mellitus Diagnosed by Oral Glucose Tolerance Testing in Cirrhotic Patients with Impaired Fasting Plasma Glucose

Objective: Use of fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) levels has been ineffective in diagnosing diabetes in cirrhotic patients. The aim of this study was to determine the prevalence and optimal cut-off levels of FPG and HbA1c for effective prediction of type 2 diabetes mellitus (T2DM) as definitely diagnosed by the 75-gram oral glucose tolerance test (75-g OGTT) in cirrhotic patients with impaired fasting plasma glucose (IFG).Material and Methods: This single-center, cross-sectional study conducted in Nan Hospital included cirrhotic patients with IFG that were diagnosed as T2DM or non-T2DM via 75-g OGTT. The clinical factors associated with the presence of T2DM were investigated using univariate and multivariate regression models.Results: T2DM was diagnosed according to 75-g OGTT in 55 of the 103 participants (53.40%); impaired glucose tolerance (IGT) was diagnosed in 22.33%, and normal OGTT results were found in 24.27%. An FPG level of ≥104.5 mg/dL and an HbA1c level of ≥5.25% were found to be the optimal cut-off levels for the prediction of T2DM. The FPG level had a sensitivity of 76.4%, 95% confidence interval (CI) [63.0%, 86.8%], and a specificity of 37.5%; 95% CI [24.0%, 52.6%]. HbA1c levels had a sensitivity of 67.3%; 95% CI [53.3%, 79.3%] and a specificity of 37.5%; 95% CI [24.0%, 52.6%]. Hepatitis C virus (HCV) infection, high Child-Pugh score, and high level of FPG before the 75-g OGTT testing were significantly associated with T2DM.Conclusion: More than half of the cirrhotic patients with IFG had T2DM diagnosed by 75-g OGTT. An FPG level of ≥104.5 mg/dL and an HbA1c level of ≥5.25% were found to be the optimal cut-off levels for the prediction of the presence of T2DM in those with cirrhosis and IFG.