Comparative effects of sitagliptin and metformin in patients with type 2 diabetes mellitus: a meta-analysis.
BACKGROUND
Sitagliptin has been widely used in the treatment of type 2 diabetes mellitus (T2DM); however, the therapeutic efficacy of sitagliptin remains inconclusive in randomized controlled studies on T2DM in which metformin has served as a control.


OBJECTIVE
The present meta-analysis aimed to compare the therapeutic efficacy of sitagliptin and metformin in the treatment of T2DM.


METHODS
We searched the following databases (Medline, Embase, Cochrane databases, Chinese Medical Journal Database, and the Chinese National Knowledge Infrastructure from inception until April 2013), and identified randomized controlled trials (RCTs) involving sitagliptin and metformin for T2DM. Two independent authors determined whether or not these trials met the inclusion criteria. Then, the variance of results from each study was calculated, and I(2) was employed for evaluation of heterogeneity.


RESULTS
One hundred and twenty-one studies were identified, of which seven were included for further analysis. For T2DM, the therapeutic efficacy of sitagliptin and metformin was comparable in reducing HbA1c (P = 0.148, standard mean difference [SMD] = 0.13, 95% confidence interval [CI] = -0.05, 0.30), decreasing BMI (P = 0.063, SMD = 0.26, 95% CI = -0.01, 0.54), and improving the homeostasis model assessment (HOMA)-β (P = 0.285, SMD = -0.05, 95% CI = -0.15, 0.04), but sitagliptin was inferior to metformin in improving HOMA-IR (P = 0.003, SMD = 0.16, 95% CI = 0.06, 0.27).


CONCLUSIONS
Sitagliptin is similar to metformin in reducing HbA1c, decreasing body weight, and improving the function of beta cells, but is inferior to metformin in improving insulin sensitivity. More RCTs with large sample sizes are required to provide evidence for the rational application of sitagliptin.
Department of Endocrinology, Shengjing Hospital of China Medical University , Shenyang , China.
Qiang
Q
Du
Bo
B
Wu
Yan-Jun
YJ
Wang
Sheng
S
Yang
Yue-Yang
YY
Zhao
Yuan-yuan
YY
Liang
D015992:Body Mass Index; D001835:Body Weight / Q000187:drug effects; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D006442:Glycated Hemoglobin / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism; D008687:Metformin / Q000009:adverse effects / Q000627:therapeutic use*; D011719:Pyrazines / Q000009:adverse effects / Q000627:therapeutic use*; D000068900:Sitagliptin Phosphate; D014230:Triazoles / Q000009:adverse effects / Q000627:therapeutic use*
D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D008687:Metformin; D011719:Pyrazines; D000068900:Sitagliptin Phosphate; D014230:Triazoles; C517652:hemoglobin A1c protein, human