Efficacy and safety of liraglutide versus sitagliptin both in combination with metformin in patients with type 2 diabetes A systematic review and meta-analysis

Background: The aim of this systematic review was to evaluate the efficacy and safety of liraglutide versus sitagliptin both in combination with metformin in patients with type 2 diabetes and provide reference basis for rational use of clinical drugs. Methods: Several databases were searched, including Web of science, PubMed, Cochrane library, CNKI, and Wanfang database. Only randomized controlled trials (RCTs) of liraglutide versus sitagliptin both in combination with metformin up to 31 August 2016 were included. Data were extracted independently by 2 reviewers, and a fixed or random effects model were used to analyze outcomes that were expressed as odds ratio (OR) or mean difference (MD) and 95% confidence intervals (95% CIs) for different situations. Results: Five RCTs involving 1440 participants were included. Compared with sitagliptin combination with metformin group, participants' treatment with 1.2mg and 1.8mg liraglutide with metformin could significantly lower the level of glycosylated hemoglobin (HbA1c) (P<.00001, MD=-0.35, 95% CI -0.51 to -0.20). Moreover, patients with 1.8mg liraglutide group had significant body weight loss (P<.00001, MD= -1.12, 95% CI -1.54 to -0.70). However, there were no obvious differences in cutting down the systolic blood pressure and diastolic blood pressure between liraglutide-metformin and sitagliptin-metformin groups. The incidence of gastrointestinal problems was significantly higher than sitagliptin with metformin groups. Conclusion: The results of this meta-analysis indicated that Liraglutide added on to metformin therapy could significantly lower the level of HbA1c and increase body weight loss. Meanwhile, the adverse reactions such as gastrointestinal problems were common in the liraglutide treatment group. Thus, this will provide an important reference for the treatment of patients with type 2 diabetes.