[Features of insulin secretion and insulin resistance in newly diagnosed type 2 diabetes of different body mass indices].

Objective: To investigate insulin secretion function and insulin resistance in Chinese newly diagnosed type 2 diabetes (obese and non-obese patients) in order to provide evidence for clinical treatment.
Methods: 408 newly diagnosed type 2 diabetes and 40 normal controls were recruited. Height, weight were measured, insulin and glucose of 0 min, 30 min, 60 min, 120 min during oral glucose tolerance test were examined. The patients with fasting glucose level greater than 8.3mmol/L were treatment with Gliclazide for 1 - 3 months. After normalization of the plasma glucose levels for more than 2 weeks, and withdraw this medication for 48 hours, then OGTT were repeated to assess IR and IS.
Results: The patients were divided into four groups based on fasting plasma glucose (DM1: FPG < 6.9mmol/L; DM2: 6.9 mmol/L < or = FPG < 8.3 mmol/L; DM3: 8.3 mmol/L < or = FPG < 9.7 mmol/L; DM4: FPG > or = 9.7 mmol/L). Every groups were further stratified to subgroups by cut point of BMI = 24 kg/m(2). Their insulin sensitivity and insulin secretion function compared between subgroups. (1) True insulin level in BMI > or = 24 (FPG < 6.9 mmol/L) subgroups were higher than control's (3.5 +/- 0.5 vs 3.2 +/- 0.6 natural logarithm) (P < 0.05). (2) In BMI > or = 24 subgroups, their insulin sensitivity were even worse than BMI < 24 groups', but their insulin secretion function were better at the same FPG level. (3) After intervention, the change of insulin sensitivity in BMI < 24 group was better than BMI > or = 24 group's (-4.7 +/- 0.9 vs -5.5 +/- 1.4 natural logarithm) (P < 0.05); but the change of insulin secretion function in BMI < 24 group was worse.
Conclusion: (1) In newly diagnostic type 2 diabetes, insulin sensitivity and insulin secretion function were decreased with the increase of FPG, but they were different between obese and non-obese group. (2) Insulin secretion function was recovered better in obese group when eliminated glucose toxicity.