Original Article
A proposed framework to guide evidence synthesis practice for meta-analysis with zero-events studies

https://doi.org/10.1016/j.jclinepi.2021.02.012Get rights and content
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Abstract

Objective

In evidence synthesis practice, researchers often face the problem of how to deal with zero-events. Inappropriately dealing with zero-events studies may lead to research waste and mislead healthcare practice. We propose a framework to guide researchers to better deal with zero-events in meta-analysis.

Study design and setting

We used two dimensions, one with respect to the total events count across all studies in the comparative arms in a meta-analysis, and a second with respect to whether included studies have single or both arms with zero-events, to establish the framework for the classification of meta-analysis with zero-events studies. A dataset from Cochrane systematic reviews was used to evaluate the classification.

Results

The proposed framework classifies meta-analysis with zero-events studies into six subtypes. The classification matched well to the large real-world dataset. The applicability of existing methods for zero-events were then presented under each meta-analysis subtype based on this framework, with a 5-step principle to help researchers in evidence synthesis practice.

Conclusions

The proposed framework should be considered by researchers when making decisions on the selection of the synthesis methods in a meta-analysis. It also provides a reasonable basis for the development of methodological guidelines to deal with zero-events in meta-analysis.

Keywords

Meta-analysis
zero-events studies
classification framework
guideline
evidence synthesis practice
decision-making

Cited by (0)

Funding: L.F.K. is funded by an Australian National Health and Medical Research Council Fellowship (APP1158469).

Conflicts of interest: None declared.

Authors’ contributions: C.X. conceived and designed the study; C.X. drafted the manuscript; L.F.K., L.Z., L.L., and S.V. provided methodological comments and revised the manuscript. All authors approved the final version to be published.