Background: Systematic review authors do not typically report the analytical methods they used to handle missing participant data (MPD) in meta-analyses. Moreover, when methods are reported, the concordance with reviewers’ actual analyses is uncertain.
Objectives: To determine which analytical methods systematic review authors actually used to deal with MPD in their meta-analyses of dichotomous outcomes, and whether there is concordance with the approach described in their methods section.
Methods: Eligible systematic reviews (SRs) reported a group-level meta-analysis of a patient-important dichotomous efficacy outcome, with a statistically significant effect estimate. We acquired the full texts of all trials included in the meta-analyses of interest. Ten reviewers working in pairs will independently abstract statistical data relevant to the meta-analysis of interest from both the SR (numerator, denominator) and the corresponding RCTs (number randomized, number with missing data, number of observed events). Then, we will compare the SR data to the corresponding trial data. Based on these comparisons, we will classify the analytical method the SR authors actually used to deal with MPD into four categories: 'complete case analysis', 'making assumptions for MPD', 'using the trialists’ assumptions', or 'excluding trials with high rate of MPD'. Then, we will assess the consistency of the method across trials included in the same meta-analysis, and concordance with the method SR authors report to have used.
Results: We included a random sample of 100 Cochrane and non-Cochrane SRs published in 2012. We identified a total of 672 RCTs included in these SRs. We are in the process of data abstraction. We will present the findings of the study at the Colloquium.
Conclusions: The findings of our study are likely to reinforce the importance of transparency in reporting and conducting SRs, particularly when dealing with MPD.