Prevalence of diabetes is increasing rapidly both in China and all over the world.Hyperglycemia is an important risk factor and major hazard to cardiovascular and cerebrovascular diseases and even dangerous to human health."High glucose toxicity "cause pancreatic β cell non-physiologic and irreversible damage.It is an important cause of β cell dysfunction.High glucose toxicity further suppresses insulin secretion of β cell, further even β-cell function failure.It is urgent to explore more effective and safety treatments which can also protect islet cells function.How to release high glucose toxicity , reverse the toxic effects of hyperglycemia on islet β cells as early as possible, and to maximize recover and protect the pancreatic β cell function is the keypoints of this study.Our aim is to explore the non-inferiority of new antidiabetic drugs DPP4 inhibitors on releasing glucose toxicity and protecting islet β cell function compared with traditional treatments on newly diagnosed type 2 diabetes,compare efficacy and safety of different oral antidiabetic drugs and insulin on newly diagnosed type 2 diabetes patients with high glucose toxicity and compare differences of different oral antidiabetic drugs and insulin on protecting pancreatic β-cell function.

Patients were divided into 3 groups:

1. DPP-4 inhibitor treatment group (45 cases): DPP-4 inhibitor (sitagliptin phosphate) combined with metformin and/or acarbose;
2. insulin treatment group (45 cases): insulin (insulin glargine or insulin detemir) and/or metformin;
3. Sulfonylureas treatment group (45 cases): sulfonylureas combined with metformin and/or acarbose;

Inclusion Criteria:

• newly onset
• type 2 diabetes
• BMI 18-30kg/m2
• FBS≧11.1mmol/L，GHbA1c≧9%
• urine ket ≦(1+)
• Normal liver and kidney function

Exclusion Criteria:

• type 1 diabetes
• renal or hepatic insufficiency
• Severe ketoacidosis
• Treatment with corticosteroids, immunosuppressive agents or cytotoxic drugs
• Severe systemic disease
• History of pancreatitis or pancreatic surgery
• Pregnant and lactating women