Increased insulinogenic index is an independent determinant of nonalcoholic fatty liver disease activity score in patients with normal glucose tolerance

BackgroundAlthough insulin resistance is involved in nonalcoholic fatty liver disease, role of abnormalities in early phase of insulin secretion has not been examined.AimsWe examined which anthropometric and metabolic parameters, including insulinogenic index during oral glucose tolerant test, were independently associated with the disease activity of nonalcoholic fatty liver disease.MethodsA total of 114 consecutive biopsy-proven nonalcoholic fatty liver disease patients without type 2 diabetes were enrolled.ResultsAge, aspartate aminotransferase, free fatty acid, ferritin type IV collagen, hyaluronic acid, procollagen N-terminal peptide, fasting plasma glucose and 2-h insulin after glucose loading were significantly higher in patients with impaired glucose tolerance than those with normal glucose tolerance. Multiple stepwise regression analysis revealed that glycated haemoglobin, decreased density ratio of liver to spleen in computed tomography and increased insulinogenic index were independently associated with nonalcoholic fatty liver disease activity score in normal glucose tolerance patients, whereas aspartate aminotransferase and 2-h insulin in impaired glucose tolerance subjects. However, there were no significant independent correlations between insulinogenic index and steatosis grade/fibrosis stage in normal glucose tolerance patients.ConclusionThe present study suggests that increased early phase of insulin secretion may contribute to nonalcoholic fatty liver disease activity score in patients with normal glucose tolerance.