- Framework of problems / Rigourous
- Small number of trials in meta-analyses
- The knowledge system underpinning healthcare is not fit for purpose and must change
Ref ID | 84 |
First Author | I. Roberts |
Journal | BMJ: BRITISH MEDICAL JOURNAL |
Year Of Publishing | 2015 |
URL | https://pubmed.ncbi.nlm.nih.gov/26041754/ |
Keywords |
Cochrane Retraction General medical |
Problem(s) |
Perpetuates citation of poor quality primary study data Small number of trials in meta-analyses |
Number of systematic reviews included | 1 |
Summary of Findings | Discusses examples of limitations of published systematic reviews including: a Cochrane review showing that high dose mannitol reduced the risk of death after head injury that was retracted after the review group editors were unable to confirm that any of the included trials took place. The authors discuss the paradox that clinical trial protocols invariably include a estimate of the sample size needed for the results to be reliable but systematic reviewers rarely estimate how many participants would need to be included in a meta-analysis for reliable results. The median number of trials in Cochrane reviews is between six and 16, and the median number of patients per trial is about 80. Consequently, most meta-analyses include small numbers of trial participants. Meta-analyses with sparse data can miss modest but clinically important treatment effects, and the potential for random error to result in false positive conclusions is considerable. The authors assert that the number of trial participants needed for a reliable meta-analysis should be at least as large as for an appropriately powered trial. |
Did the article find that the problem(s) led to qualitative changes in interpretation of the results? | Not Applicable |
Are the methods of the article described in enough detail to replicate the study? |