Eligibility criteria in systematic reviews published in prominent medical journals: a methodological review

Abstract

Rationale and aim: Clear and logical eligibility criteria are fundamental to the design and conduct of a systematic review. This methodological review examined the quality of reporting and application of eligibility criteria in systematic reviews published in three leading medical journals.

Methods: All systematic reviews in the BMJ, JAMA and The Lancet in the years 2013 and 2014 were extracted. These were assessed using a refined version of a checklist previously designed by the authors.

Results: A total of 113 papers were eligible, of which 65 were in BMJ, 17 in The Lancet and 31 in JAMA. Although a generally high level of reporting was found, eligibility criteria were often problematic. In 67% of papers, eligibility was specified after the search sources or terms. Unjustified time restrictions were used in 21% of reviews, and unpublished or unspecified data in 27%. Inconsistency between journals was apparent in the requirements for systematic reviews.

Conclusions: The quality of reviews in these leading medical journals was high; however, there were issues that reduce the clarity and replicability of the review process. As well as providing a useful checklist, this methodological review informs the continued development of standards for systematic reviews.

Keywords: bias; eligibility criteria; meta-analysis; reporting; review; systematic review.