Supplementary materials: Recommendations from Cochrane reviews for improving future trials on anesthesia and pain: a meta-research study

These are peer-reviewed supplementary materials for the article 'Recommendations from Cochrane reviews for improving future trials on anesthesia and pain: a meta-research study' published in the Journal of Comparative Effectiveness Research.

• Supplementary file 1: List of excluded studies with reasons for exclusion
• Supplementary file 2: Cochrane systematic reviews included in the study
• Supplementary file 3: Frequency of all categories of recommendations
• Supplementary file 4: List of studies included in 'Trials of this type are not a priority / are unlikely' category, corresponding Cochrane Review Group, verbatim and categorization of reasons for their inclusion

Background: Cochrane systematic reviews (CSRs) have a section ‘Implications for research’ where authors make suggestions for improving future research. The authors of the present study assessed the prevalence and time dynamics of different recommendations in the CSRs about anesthesia and pain. Methods: The authors included all CSRs published by the Cochrane Anaesthesia Group and Cochrane Pain and Palliative Care Group before 17 July 2020. The authors analyzed recommendations for improving future research listed in the ‘Implications for research’ section of these CSRs and categorized recommendations for improvements. Results: They analyzed 370 reviews. Four categories of recommendations were present in more than 40% of the reviews. Most reviews recommended a larger sample size and better outcome choice, study design and choice of future intervention. These recommendations gradually increased in frequency in the Cochrane Pain and Palliative Care Group and mainly decreased in the Cochrane Anaesthesia Group. Conclusion: Recommendations from CSRs offer useful advice for trialists designing new trials.