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

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. To assess the methodological quality of MAs on COPD treatments. 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. 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. 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. A new study highlights widespread methodological flaws in meta-analyses of chronic obstructive pulmonary disease (COPD) trials. Meta-analyses of clinical trials allow researchers to combine the results of several independent studies with the aim of providing a more precise estimate of a treatment’s effect. Vincent Chung and his team at The Chinese University of Hong Kong assessed the methodological quality of 79 meta-analyses on COPD treatments published between 2000 and 2013. They found that only 18% of the analyses considered the scientific quality of the primary studies and only 49% used the appropriate statistical methods. They also noticed a lack of reporting on conflict of interest, harm, publication bias (positive findings) and language bias (English). Such issues greatly reduce the validity of the meta-analyses’ conclusions and can mislead clinical practice.