Relative Impact of Insulin Secretion and Sensitivity on Glycemic Control

Although both insulin secretion and sensitivity affect glycemic control, insulin secretion was the major determinant of glycemic control in patients with type 2 diabetes.

A group of researchers led by Dr Louis Monnier of the University Institute of Clinical Research in Montpellier, France, assessed the relative impact of insulin secretion and sensitivity on glycemic control in insulin-naive patients with type 2 diabetes. HbA1c, insulin sensitivity (estimated using the homeostasis model assessment [HOMA]2-%S), and insulin secretion (HOMA2-%B) were measured in 289 patients treated with metformin (n=57) or metformin and glyburide (n=232).

The researchers found that HOMA2-%B contributed more to HbA1c than HOMA2-%S, using stepwise multiple regression in patients treated with metformin (33.5% vs 23.4%) or metformin plus glyburide (22.7% vs 8%). Patients treated with metformin with HOMA2-%B of <50% had increased HbA1c, compared with 2 subsets of patients with HOMA2-%B 50% or more (8.4% vs 7.2% and 6.8%; p=0.0013). In patients treated with metformin and glyburide, HOMA2-%B was greater in those with HbA1c <8%, compared with those with HbA1c values of 8% or more (55.1% vs 40.7% and 30.1%; p<0.0001). No differences were found with respect to HOMA2-%S.

The researchers concluded that, although both insulin secretion and sensitivity affect glycaemic control, insulin secretion was the major determinant of glycaemic control in patients with type 2 diabetes treated with metformin alone or metformin plus glyburide.
European Journal of Clinical Investigation 2006;36:231-5