title: Methodological quality of meta-analyses on treatments for chronic obstructive pulmonary disease: a cross-sectional study using the AMSTAR (Assessing the Methodological Quality of Systematic Reviews) tool.
abstract: BACKGROUND
  Meta-analysis (MA) of randomised trials is considered to be one of the best approaches for summarising high-quality evidence on the efficacy and safety of treatments. However, methodological flaws in MAs can reduce the validity of conclusions, subsequently impairing the quality of decision making.
  
  
  OBJECTIVE
  To assess the methodological quality of MAs on COPD treatments.
  
  
  METHODS
  A cross-sectional study on MAs of COPD trials. MAs published during 2000-2013 were sampled from the Cochrane Database of Systematic Reviews and Database of Abstracts of Reviews of Effect. Methodological quality was assessed using the validated AMSTAR (Assessing the Methodological Quality of Systematic Reviews) tool.
  
  
  RESULTS
  Seventy-nine MAs were sampled. Only 18% considered the scientific quality of primary studies when formulating conclusions and 49% used appropriate meta-analytic methods to combine findings. The problems were particularly acute among MAs on pharmacological treatments. In 48% of MAs the authors did not report conflict of interest. Fifty-eight percent reported harmful effects of treatment. Publication bias was not assessed in 65% of MAs, and only 10% had searched non-English databases.
  
  
  CONCLUSIONS
  The methodological quality of the included MAs was disappointing. Consideration of scientific quality when formulating conclusions should be made explicit. Future MAs should improve on reporting conflict of interest and harm, assessment of publication bias, prevention of language bias and use of appropriate meta-analytic methods.
authors.affiliation: Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Robin S T
authors.initials: RS
authors.lastname: Ho
authors.affiliation: Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Xinyin
authors.initials: X
authors.lastname: Wu
authors.affiliation: Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Jinqiu
authors.initials: J
authors.lastname: Yuan
authors.affiliation: Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Siya
authors.initials: S
authors.lastname: Liu
authors.affiliation: Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Xin
authors.initials: X
authors.lastname: Lai
authors.affiliation: Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Samuel Y S
authors.initials: SY
authors.lastname: Wong
authors.affiliation: 1] Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong [2] Hong Kong Institute of Integrative Medicine, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Vincent C H
authors.initials: VC
authors.lastname: Chung
mesh_terms: D003430:Cross-Sectional Studies; D006801:Humans; D015201:Meta-Analysis as Topic; D015999:Multivariate Analysis; D017063:Outcome Assessment, Health Care; D017594:Publication Bias; D029424:Pulmonary Disease, Chronic Obstructive / Q000628:therapy*; D016032:Randomized Controlled Trials as Topic; D015203:Reproducibility of Results