Abstract: Objective To investigate the application effect of dapagliflozin combined with metformin in obese/overweight type 2 diabetes mellitus(T2DM) and its effect on intestinal microbiota, adropin, chemerin, and irisin. 
Methods According to the computerized random number table method, 112 obese/overweight T2DM patients were divided into two groups in a 1∶1 ratio, with 56 cases in each group. The control group was treated with metformin, and the observation group was treated with dapagliflozin combined with metformin. The blood glucose levels［fasting blood glucose(FPG), 2 h postprandial blood glucose(2 hPG), glycosylated hemoglobin A1c(HbA1c)］, homeostasis model assessment-insulin resistance(HOMA-IR), waist circumference, body mass index(BMI), blood lipid indexes［high density lipoprotein(HDL-C), triacylglycerol(TG), low density lipoprotein(LDL-C), total cholesterol(TC)］, intestinal microbiota, serum adropin, chemerin, irisin and adverse reactions were compared between the two groups. 
Results The FPG, 2 hPG, HbA1c and HOMA-IR of the observation group were lower than those of the control group at 3 months and 6 months after treatment(P＜0.05). The waist circumference and BMI of the observation group were lower than those of the control group at 6 months after treatment(P＜0.05). At 3 and 6 months after treatment, TG was lower in the observation group than in the control group, and HDL-C was higher than that of the control group(P＜0.05). The number of Enterococcus and Enterobacter in the observation group at 6 months after treatment was lower than that of the control group, while the number of Bacteroides and Lactobacillus was higher than that of the control group(P＜0.05). In the observation group, adropin and irisin were higher than those in the control group at 3 and 6 months after treatment, while chemerin was lower than that in the control group(P＜0.05). 
Conclusion Dapagliflozin combined with metformin in the treatment of obesity/overweight T2DM can effectively reduce blood glucose levels, improve insulin resistance, blood lipid metabolism and intestinal microecology, relieve obesity/overweight, and have high safety. Decreasing chemerin and increasing adropin and irisin may be a molecular mechanism for the combined anti-T2DM effect of the two. 

Key words: diabetes mellitus, type 2, dapagliflozin, metformin