The use of systematic reviews to justify anaesthesiology trials: A meta-epidemiological study.

AIMS: New randomized clinical trials (RCTs) should be initiated if previous systematic reviews (SRs) indicate that new trials are needed. We analysed whether RCTs published in anaesthesiology journals mentioned previous SRs as a rationale for conducting trial and for discussing results.

METHODS: This was a meta-epidemiological, descriptive cross-sectional study. We analysed RCTs published in the seven first-quartile anaesthesiology journals between 2014 and 2016. We studied text and bibliography of the RCTs to assess whether the authors made a reference to previous SRs when justifying the need for their own clinical trial and discussing the results.

RESULTS: In the 622 studied RCTs 126 (20%) mentioned verbatim or cited one or more SRs as justification for conducting a trial, most commonly in introduction of a manuscript. Almost half of the included RCTs (44%) did not cite a single systematic review. There was no significant difference between the years in the number of explicitly mentioned SRs as justification for conducting a trial (F = 0.540, p = 0.583). Trials citing, mentioning or explicitly using SRs as a justification were published in journals with significantly higher impact factor and included significantly higher number of participants, while there was no difference in using SRs in trials in terms of funding type, type of intervention or positive versus negative results.

CONCLUSIONS: Trialists should use evidence from existing SRs for planning a trial, while ethics committees, peer-reviewers and editors should require authors to provide evidence that a new trial is indeed necessary.

SIGNIFICANCE: Since less than a fifth of trials published in high-impact journals in the field of anaesthesiology explicitly mention previous systematic review as a justification for conducting the trial, authors, ethics committees, editors and peer-reviewers need to increase their awareness of the need for proper justification regarding the necessity for a new trial.