I. What is diabetes mellitus? Diabetes mellitus is a metabolic disorder characterized by chronic hyperglycemia caused by multiple etiologies, accompanied by abnormalities in sugar, fat and protein metabolism due to defective insulin secretion and/or action. What are the clinical features of diabetes mellitus? The main clinical signs are “three more and one less”, i.e. drinking more, eating more, urinating more and losing weight. How can I determine if I have diabetes? (2010 ADA Diabetes Diagnostic Criteria) 1. Glycosylated hemoglobin A1c≥6.5%. 2, fasting blood glucose FPG≥7.0 mmol/l. Fasting is defined as no caloric intake for at least 8h. 3, 2h blood glucose ≥ 11.1 mmol/l at oral glucose tolerance test. 4, Random blood glucose ≥ 11.1 mmol/l in patients with typical symptoms of hyperglycemia or hyperglycemic crisis. In the absence of definite hyperglycemia, criteria 1~3 should be confirmed by repeat testing.