Hepatic insulin resistance affects the efficacy of metformin in patients with newly diagnosed type 2 diabetes: A Sub-Analysis of the MARCH trial.

AIM

Our study aimed to analyze how hepatic insulin resistance (IR) influences the efficacy of 48 weeks of metformin treatment in newly diagnosed type 2 diabetes patients.

METHODS

We chose 291 participants who were allocated to a 48-week metformin treatment in the "Metformin and Acarbose in Chinese as initial Hypoglycemic treatment" (MARCH) trial and calculated their hepatic insulin resistance indexes (HIRI). We equally grouped the subjects into tertiles: low, medium, and high HIRI groups based on baseline HIRI; Low, medium, and high ΔHIRI groups based on the decreasing extent of HIRI after a 48-week metformin treatment.

RESULTS

Multiple linear regression showed that baseline HIRI was positively associated with the rising degree of Matsuda index and the falling range of fasting blood glucose, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and HIRI. Furthermore, baseline fasting insulin, homeostatic model assessment of β cell function (HOMA-β), HOMA-IR, and HIRI were positively associated with the decreasing extent of HIRI, while baseline Matsuda index had a negative association with the falling extent of HIRI.

CONCLUSIONS

Patients with higher levels of hepatic IR obtained better curative effects from metformin in terms of glycemic control, insulin saving, insulin sensitivity enhancement, and IR improvement. Higher fasting blood glucose, fasting insulin, HOMA-β, IR, and lower Matsuda index were indicators of better hepatic IR improvement.