Heterogeneity can impair the results of Cochrane meta‐analyses despite accordance with statistical guidelines

Ref ID 173
First Author H.-J. Malling
Journal ALLERGY
Year Of Publishing 2008
URL https://onlinelibrary.wiley.com/doi/pdfdirect/10.1111/j.1398-9995.2008.01908.x?download=true
Keywords Cochrane
Heterogeneity
Immunology
Problem(s) Inadequate analysis of heterogeneity
Weaknesses identified in some Cochrane reviews
Number of systematic reviews included 1
Summary of Findings The authors re-examined the meta-analysis and ultimate treatment effect of the Cochrane review on the effect of specific immunotherapy in patients with seasonal allergic rhinitis published in 2007. They found that excluding studies identified as extreme outliers from the original meta-analysis (as the authors state is generally advised within statistics) using influence statistics helped identify outliers and reasons for heterogeneity. As such, justifications for exclusion due to clinical or methodological heterogeneity were provided for exclusions of outlier studies in the meta-analysis.
Did the article find that the problem(s) led to qualitative changes in interpretation of the results? No
Are the methods of the article described in enough detail to replicate the study? Yes