title: Comparison of glucose lowering effect of metformin and acarbose in type 2 diabetes mellitus: a meta-analysis.
abstract: BACKGROUND
  Metformin is the first-line oral hypoglycemic agent for type 2 diabetes mellitus recommended by international guidelines. However, little information exists comparing it with acarbose which is also commonly used in China. This study expanded knowledge by combining direct and indirect evidence to ascertain the glucose lowering effects of both drugs.
  
  
  METHODS
  PubMed (1980- December 2013) and China National Knowledge Infrastructure databases (1994-January 2014) were systematically searched for eligible randomized controlled trials from Chinese and English literatures. Meta-analysis was conducted to estimate the glucose lowering effects of metformin vs. acarbose, or either of them vs. common comparators (placebo or sulphonylureas), using random- and fixed-effect models. Bucher method with indirect treatment comparison calculator was applied to convert the summary estimates from the meta-analyses into weighted-mean-difference (WMD) and 95% confidence intervals (CIs) to represent the comparative efficacy between metformin and acarbose.
  
  
  RESULTS
  A total of 75 studies were included in the analysis. In direct comparison (8 trials), metformin reduced glycosylated hemoglobin (HbA1c) by 0.06% more than acarbose, with no significant difference (WMD,-0.06%; 95% CI, -0.32% to 0.20%). In indirect comparisons (67 trials), by using placebo and sulphonylureas as common comparators, metformin achieved significant HbA1c reduction than acarbose, by -0.38% (WMD,-0.38%, 95% CI, -0.736% to -0.024%) and -0.34% (WMD, -0.34%, 95% CI, -0.651% to -0.029%) respectively.
  
  
  CONCLUSIONS
  The glucose lowering effects of metformin monotherapy and acarbose monotherapy are the same by direct comparison, while metformin is a little better by indirect comparison. This implies that the effect of metformin is at least as good as acarbose's.
authors.affiliation: Center for Health Policy Studies, School of Public Health, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, China.
authors.forename: Shuyan
authors.initials: S
authors.lastname: Gu
authors.affiliation: Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, China.
authors.forename: Jihao
authors.initials: J
authors.lastname: Shi
authors.affiliation: Health Economics and Outcome Research (HEOR), Bristol-Myers Squibb, Shanghai City, China.
authors.forename: Zhiliu
authors.initials: Z
authors.lastname: Tang
authors.affiliation: College of Health Professions, Marshall University, Huntington, West Virginia, United States of America.
authors.forename: Monika
authors.initials: M
authors.lastname: Sawhney
authors.affiliation: Center for Health Policy Studies, School of Public Health, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, China.
authors.forename: Huimei
authors.initials: H
authors.lastname: Hu
authors.affiliation: Department of Global Health Systems and Development, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, United States of America.
authors.forename: Lizheng
authors.initials: L
authors.lastname: Shi
authors.affiliation: Section of Endocrinology, Department of Medicine, School of Medicine, Tulane University, New Orleans, Louisiana, United States of America.
authors.forename: Vivian
authors.initials: V
authors.lastname: Fonseca
authors.affiliation: Center for Health Policy Studies, School of Public Health, Zhejiang University School of Medicine, Hangzhou City, Zhejiang Province, China.
authors.forename: Hengjin
authors.initials: H
authors.lastname: Dong
mesh_terms: D020909:Acarbose / Q000627:therapeutic use*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D008297:Male; D008687:Metformin / Q000627:therapeutic use*
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin; D020909:Acarbose