Several meta-analyses published in medical literature do not adhere to appropriate design protocols or provide a clinically meaningful contribution to medical practice and patient care, according to a paper published in Circulation.

Milton Packer, MD, of the Baylor Heart and Vascular Institute at Baylor University Medical Center in Dallas, Texas, defines a meta-analysis as a “mathematical method for combining data, which is weighted by the quantity but not the quality of the observations.” To increase precision and confidence in results, trials included in meta-analyses should have varying designs, treatment doses, and methods for observation. In instances when a meta-analysis is improperly designed, clinically relevant results may be more accurately depicted in a randomized, large-scale trial.

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Dr Packer suggests a number of different factors that readers should look for in a meta-analysis to determine its strengths and limitations. First, the number of events in a pooled analysis should be appropriately sized to offer replicable truth. For the analysis to provide a reliable estimate of clinical events observed in clinical practice, Dr Packer suggests a total event number greater than 200 to 300.

Additionally, meta-analyses should include trials that have comparator groups, such as the effect of one treatment over another or the effect of an intervention vs no intervention. Dr Packer suggests that a meta-analysis should offer clinically useful insights that go beyond the data’s narrative summary.

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Overall, meta-analyses are important aspects of medical research, but only when properly designed and interpreted with findings that will affect patient care. When a meta-analysis provides novel findings that mirror, “the design of their component trials and are based on a meaningful amount of evidence…[they] can yield an answer whose reliability approximates or exceeds that of a single definitive trial.”


Packer M. Are meta-analyses a form of medical fake news? Thoughts about how they should contribute to medical science and practice.  Circulation. 2017;136(22):2097-2099.