Meta-analysis with zero-event studies: a comparative study with application to COVID-19 data

Jia Jin Wei, En Xuan Lin, Jian Dong Shi, Ke Yang, Zong Liang Hu, Xian Tao Zeng, Tie Jun Tong*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

15 Citations (Scopus)


Meta-analysis is a statistical method to synthesize evidence from a number of independent studies, including those from clinical studies with binary outcomes. In practice, when there are zero events in one or both groups, it may cause statistical problems in the subsequent analysis.

In this paper, by considering the relative risk as the effect size, we conduct a comparative study that consists of four continuity correction methods and another state-of-the-art method without the continuity correction, namely the generalized linear mixed models (GLMMs). To further advance the literature, we also introduce a new method of the continuity correction for estimating the relative risk.

From the simulation studies, the new method performs well in terms of mean squared error when there are few studies. In contrast, the generalized linear mixed model performs the best when the number of studies is large. In addition, by reanalyzing recent coronavirus disease 2019 (COVID-19) data, it is evident that the double-zero-event studies impact the estimate of the mean effect size.

We recommend the new method to handle the zero-event studies when there are few studies in a meta-analysis, or instead use the GLMM when the number of studies is large. The double-zero-event studies may be informative, and so we suggest not excluding them.
Original languageEnglish
Article number41
JournalMilitary Medical Research
Early online date3 Jul 2021
Publication statusPublished - Dec 2021

Scopus Subject Areas

  • Statistics and Probability
  • Medicine(all)

User-Defined Keywords

  • Continuity correction
  • Coronavirus disease 2019 data
  • Meta-analysis
  • Relative risk
  • Zero-event studies


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