The change of glycemic variation and insulin dose after adding SGLT2 inhibitor in type 2 diabetic patients treated with basal insulin was observed in a single center.

Inclusion Criteria:

1. Patients with T2DM, which was defined bypublished Criteria of World Health Organization in 1999;
2. Patients were using glargine with or without oral hypoglycemic drugs and having a stable dose of glargine for more than 2 month would be recruited into this study;
3. Patients had relatively constant diet and exercise in 2 month before the study.
4. Fasting blood glucose was between 6.1 and 16mmolL, and postprandial (or random) blood glucose <22.2mmol/L

Exclusion Criteria:

1. Patients with severe cardiovascular diseases, such as stroke, transient ischemic attack, myocardial infarction, unstable angina, coronary artery bypass grafting, percutaneous coronary intervention, and heart failure;
2. Patients with severe infectious diseases;
3. Patients with acute complications of diabetes on admission, such as diabetic ketoacidosis, diabetic hyperosmolar nonketotic coma, and lactic acidosis;
4. Patients with history of psychiatric disorders and were unsuitable to use CGMS;
5. Patients used GLP-1 analogues，SGLT2 or more than once insulin injection in the past 3 months
6. Any other situations that made patients unsuitable to participate in the study, such as alcoholism and drug abuse.