Comparative effects of sitagliptin and metformin in patients with type 2 diabetes mellitus: a meta-analysis

Abstract

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.

Objectives:

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.

Keywords::

• Meta-analysis
• Metformin
• Sitagliptin
• T2DM

Transparency

Declaration of funding

The authors received no payment in preparation of this manuscript.

Declaration of financial/other relationships

Q.D., B.W., Y.-J.W., S.Y., Y.-Y.Z., and Y.y.L. have disclosed that they have no significant relationships with or financial interests in any commercial companies related to this study or article.

CMRO peer reviewers may have received honoraria for their review work. The peer reviewers on this manuscript have disclosed that they have no relevant financial relationships.

Acknowledgments

The authors thank the research team at the Department of Endocrinology, Shengjing Hospital of China Medical University for their assistance with this study.