Reporting of meta-analyses of randomized controlled trials with a focus on drug safety: an empirical assessment.

Background: Due to the sparse nature of serious drug-related adverse events (AEs), meta-analyses combining data from several randomized controlled trials (RCTs) to evaluate drug safety issues are increasingly being conducted and published, influencing clinical and regulatory decision making. Evaluation of meta-analyses involves the assessment of both the individual constituent trials and the approaches used to combine them. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting framework is designed to enhance the reporting of systematic reviews and meta-analyses. However, PRISMA may not cover all critical elements useful in the evaluation of meta-analyses with a focus on drug safety particularly in the regulatory-public health setting.

Purpose: This work was conducted to (1) evaluate the adherence of a sample of published drug safety-focused meta-analyses to the PRISMA reporting framework, (2) identify gaps in this framework based on key aspects pertinent to drug safety, and (3) stimulate the development and validation of a more comprehensive reporting tool that incorporates elements unique to drug safety evaluation.

Methods: We selected a sample of meta-analyses of RCTs based on review of abstracts from high-impact journals as well as top medical specialty journals between 2009 and 2011. We developed a preliminary reporting framework based on PRISMA with specific additional reporting elements critical for the evaluation of drug safety meta-analyses of RCTs. The reporting of pertinent elements in each meta-analysis was reviewed independently by two authors; discrepancies in the independent evaluations were resolved through discussions between the two authors.

Results: A total of 27 meta-analyses, 12 from highest impact journals, 13 from specialty medical journals, and 2 from Cochrane reviews, were identified and evaluated. The great majority (>85%) of PRISMA elements were addressed in more than half of the meta-analyses reviewed. However, the majority of meta-analyses (>60%) did not address most (>80%) of the additional reporting elements critical for the evaluation of drug safety. Some of these elements were not addressed in any of the reviewed meta-analyses.

Limitations: This review included a sample of meta-analyses, with a focus on drug safety, recently published in high-impact journals; therefore, we may have underestimated the extent of the reporting problem across all meta-analyses of drug safety. Furthermore, temporal trends in reporting could not be evaluated in this review because of the short time interval selected.

Conclusions: While the majority of PRISMA elements were addressed by most studies reviewed, the majority of studies did not address most of the additional safety-related elements. These findings highlight the need for the development and validation of a drug safety reporting framework and the importance of the current initiative by the Council for International Organizations of Medical Sciences (CIOMS) to create a guidance document for drug safety information synthesis/meta-analysis, which may improve reporting, conduct, and evaluation of meta-analyses of drug safety and inform clinical and regulatory decision making.