Congenital diaphragmatic hernia: a meta-analysis of mortality factors

CRD COMMENTARY:

This study was based on clear inclusion criteria and a reasonable search of the literature. However, only articles published in English were included and this may lead to publication bias, as the authors acknowledged in their discussion of the review's findings. In addition, no details of the number of reviewers involved in the study selection and data extraction processes, and how these processes were performed, were provided. Consequently, no comment can be made about the risk of bias with regards to the review methodology.
A variety of studies were included in the review. Some details of the studies were tabulated, but there was very little information on the study design, nature and accuracy of the diagnostic test, study setting and the participants. In addition, the validity of the studies was not assessed. A statistical test for heterogeneity was performed before the studies were pooled statistically, but some studies might have been pooled despite evidence of clinical heterogeneity. Based on the limited information provided, the analysis would appear to be valid. The authors also discussed a number of issues and problems associated with the review. The authors' conclusions and implications for practice appear reasonable given the data presented, but should be viewed with caution considering the limitations of the review.