Effect Of Metformin In Newly Diagnosed Type 2 Diabetes Mellitus

Objective:To investigate the changes of the glucose levels, glucose variations, insulin sensitivity and islet function in newly diagnosed type 2 diabetes mellitus after short period of metformin treatment, analyses the possible influence elements, in order to provide reference of more rational treatment.Methods:21 newly diagnosed type 2 diabetes were given life style intervene and metformin (0.5g tid) treatment for 12 weeks. Flow-up once a week was taken at first 3 weeks, then flow-up once a month. All the follow exams were executed before and after the treatment.5 normal 75g glucose tolerance volunteers were taken as control.(1) Collection of general conditions;(2) Continuous glucose monitoring system (CGMS):calculate mean glucose levels and glucose variation coefficients;(3) Hyperinsulinemic euglycemic clamp test (HECT):calculate M value and other simple indices of insulin sensitivity.(4) Intravenous glucose tolerance test (IVGTT):Calculate AIR and other simple indices of islet function.Result:(1) General condition:weight, BMI, waist and waist/hip were decreased after treatment (P<0.05orP<0.01), plasma lipid only partly improved(2) glucose levels and variations:①Mean glucose levels, SD and CV dropped obviously after treatment (P<0.01).②CV-PBG and CV-night occupied the most important place in daily variation.③All glucose variation indices were related with HbAlc and AIR. Step-wise regression showed that MBG,PBG and CV-night were the glucose elements that effected HbAlc. HbAlc had positive relation with M value,2hINS and Alb/Cr, and negative relation with 2hCP.(3) Insulin sensitivity:①M value of the newly diagnosed type 2 diabetes was 71.8% of the normal glucose tolerance control (P<0.01), which increased significantly after treatment (P<0.01) and no longer had difference with the control.②Compared of the clamp showed that 30-60min glucose level had relation with insulin sensitivity. The main effect of insulin resistance on GIR included 3 aspects:delaying the time of reaching platform, elevating variation, and decreasing the GIR of the last hour.③Step-wise regression showed that M-PBG,M-FBG,MBG were the glucose elements that related with M value; Age,waist/hip,TG and LDL were related with M value; M value had positive relation with FINS and negative relation with 2hCP.(4) Islet function:①AIR was significantly decreased in newly diagnosed diabetes mellitus, which was elevated after treatment and still lower obviously than control (P<0.01).②Comparing of the IVGTT curves showed that:insulin level of newly diagnosed diabetes elevated in base line when compared with control, while insufficiently after intravenous glucose burden with lower insulin level of curve peak; insulin curves and glucose curves ameliorated after treatment though still far from control.③Step-wise regression showed that MBG,PBG,M-night,FINS,TC,SD and M value were related with AIR; h-duration,AIR,MBG,FBG and M value were relation with glucose disposition index (DI).Conclusion:(1) Glucose levels and variations:Mean glucose levels and variations decrease sharply. MBG and PBG are the mainly causes that influenced HbAlc, glucose variation is an independent element that effected HbAlc, as well as insulin sensitivity and islet function. Lowering HbAlc will be helpful in putting off the microvascular complications.(2) Insulin sensitivity:Heavy insulin resistance exists in newly diagnosed type 2 diabetes mellitus, which improves obviously after treatment mainly by ameliorating hepatic and skeleton muscle insulin sensitivities. PBS has close relation with insulin sensitivity. Insulin sensitivity is also influenced by lipid level, as well as age and abdomen fat.(3) Islet function:Isletβcell function of china newly diagnosed type 2 diabetes mellitus is bad, life style and metformin treatment could ameliorate islet function to some content. AIR relates more with PBG than FBG; the increase of AIR could decrease the mean glucose level and glucose variation of whole day. Islet function plays more important role than insulin sensitivity in glucose disposition.(4) Treatment proposal:Metformin is a efficient and safe treatment protocol for newly diagnosed type 2 diabetes. Intensive control of glucose and lipid will do help to ameliorating insulin sensitivity, protecting islet function and preventing diabetes vascular complications.