Objective: To investigate insulin resistance and islet beta cell function in type 2 diabetes mellitus (T2DM) and non alcoholic fatty liver disease (NAFLD).
Methods: Two hundred and six study subjects were classified into 4 groups. Hepatic insulin resistance index (HIR), HOMA insulin resistance index (HOMA-IR) and Matsuda index (MSI) were used to assess insulin resistance. HOMA-beta, early and late phase indexes of insulin secretion were used to evaluate islet beta cell function.
Results: HIR in the NAFLD group and T2DM with NAFLD group were significantly higher than that in the control group and T2DM group (4.13 +/- 0.64, 4.03 +/- 0.69 vs 3.52 +/- 0.78, 3.53 +/- 0.64, P < 0.05), HOMA-IR in the T2DM with NAFLD group was significantly higher than that in the NAFLD group and T2DM group (3.35 +/- 2.69 vs 2.31 +/- 1.39, 2.40 +/- 1.55, P < 0.05). Early phase insulin secretion index in the NAFLD group was lower than that in the control group significantly (2.13 +/- 0.17 vs 2.61 +/- 0.13, P < 0.05), but there was no significant difference of HOMA-beta and late phase insulin secretion index between the NAFLD group and control group, HOMA-beta, early and late phase indexes of insulin secretion in the T2DM group and T2DM with NAFLD group were significantly lower than those in the control group.
Conclusions: Normal glucose tolerance NAFLD patients may present with insulin resistance, mainly hepatic insulin resistance. Islet beta cell function in the NAFLD patients show damage of early phase insulin secretion. Newly diagnosed T2DM with or without NAFLD patients generally present with insulin resistance, early and later phase insulin secretion dysfunction. Insulin resistance in patients with T2DM and NAFLD is more severe.