Effect of Dapagliflozin on Glycemic Variability

Inclusion Criteria: 1. Female and male aged 20\~70 years 2. Type 2 diabetes patients 3. Treatment on basal insulin therapy ≥0.2U/kg/day(±metformin and/or ±sulfonylurea) for at least 12 weeks 4. Inadequate glycemic control ; HbA1c 7.0%\~10.0% at screening 5. Female of childbearing potential agrees to routinely use of adequate contraception from signing of the informed consent throughout the duration of the study 6. Understands the study procedure, alternatives, and risks and voluntarily agrees to participated by giving written informed consent Exclusion Criteria: 1. Type 1 diabetes(Fasting C-peptide ≤ 0.78ng/dL(or 0.26 nM/L)), secondary diabetes, gestational diabetes 2. Insulin therapy modalities containing short or rapid acting insulin (continuous subcutaneous insulin injection, pre-mixed insulin, basal-bolus insulin) 3. History of diabetic ketoacidosis, hyperglycemic hyperosmolar state 4. Estimated glomerular filtration rate \<60 mL/min/1.73 m2 5. History of chronic cystitis or recurrent urinary tract infection 6. Currently on loop diuretics 7. Adrenal insufficiency, pituitary insufficiency 8. Currently on medication known to affect glucose metabolism (e.g. corticosteroids, immunosuppressants) 9. Hemoglobin \<10g/dL in female, \<12g/dL in male 10. Abnormal liver function (AST/ALT \> x3 upper normal limit) 11. On weight loss program or taking weight loss medication 12. NYHA class III, IV congestive heart failure 13. History of acute myocardial infarction, unstable angina, coronary artery bypass graft or stroke within 6 months 14. History of bladder cancer 15. History of malignancy within 5 years 16. Pregnant or lactating women 17. History of excessive alcohol abuse (≥30g/day) 18. Hypersensitivity to SGLT2 inhibitors 19. Patient with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption. 20. Subject who the investigator deems inappropriate to participate in this study