Predictors of Insulin Secretion in Japanese Patients with Histopathologically-confirmed Non-alcoholic Fatty Liver Disease

OBJECTIVE: The correlation between the insulin secretion levels and the risk of hepatocarcinogenesis is clinically important. The aim of the present study was to determine the effects of various clinical parameters on C-peptide (CPR) levels in patients with non-alcoholic fatty liver disease (NAFLD). METHODS: In this retrospective cohort study, the effects of clinical parameters on insulin resistance (HOMA-IR) and insulin secretion levels (HOMA-β and fasting CPR) were investigated. PATIENTS: A total of 244 Japanese patients with histopathologically confirmed NAFLD were evaluated. Of these, 77 underwent the meal tolerance test (MTT) to evaluate the association of various clinical parameters with the CPR levels at 120 minutes. RESULTS: A multivariate analysis identified fasting plasma glucose (FPG) (≥110 mg/dL), aspartate aminotransferase (≥1.0×ULN IU/L), and a large waist circumference as independent predictors of insulin resistance (HOMA-IR ≥2.5) or high fasting CPR levels. Significant parameters for a low insulin secretion capacity (HOMA-β <30%) were not detected, except for the parameters mentioned in the diagnostic criteria of diabetes mellitus. Regarding the MTT, the CPR levels at 120 minutes were significantly higher in patients with fibrosis stage 3-4 than in those with stage 0-2. Body composition and genetic variation did not affect the CPR levels at 120 minutes. A multivariate analysis identified fibrosis stage (3-4), hyperuricemia, FPG (≥110 mg/dL), and procollagen III peptide (>1.0 U/mL) as independent predictors of high CPR levels at 120 minutes. CONCLUSION: The present study showed that high plasma glucose levels and severe liver fibrosis stage influence insulin secretion levels in Japanese patients with NAFLD. Conservation of delayed insulin secretion levels was confirmed in patients with severe liver fibrosis.