Article type
Year
Abstract
Background: Reports of randomized clinical trials (RCTs) do not always specify whether participants belonging to certain categories (e.g. those who withdraw consent, non-compliers) were followed-up for the outcome(s) of interest or not (i.e. missing participant data (MPD)). Systematic reviewers may, therefore, have to make assumptions on whether data from these participants is missing.
Objectives: To describe characteristics, reporting and handling of categories of participants that could be potentially counted as having MPD in RCTs included in Cochrane and non-Cochrane systematic reviews (SRs).
Methods: We selected a random sample of 100 Cochrane and non-Cochrane SRs published in 2012. Eligible SRs reported a group-level meta-analysis of a patient-important dichotomous efficacy outcome, with a statistically significant effect estimate. Ten reviewers, working in pairs, independently extracted data from the RCTs included in eligible meta-analyses. We focused on 10 categories that could be potentially counted as MPD: 'participants deemed ineligible after randomization', 'did not receive any treatment', 'withdrew consent', 'outcome not assessable', 'explained and unexplained lost to follow-up', 'dead', 'experienced adverse events', 'non-compliant', 'discontinued prematurely', and 'cross-over'. We specifically assessed: 1) the number of participants in those categories; 2) whether trialists explicitly reported on the follow-up status of those participants; and 3) how trialists handled those participants in their analysis.
Results: We included a total of 672 RCTs included in 100 eligible Cochrane and non-Cochrane SRs. We are in the process of data abstraction. We will present the findings of the study at the Colloquium.
Conclusions: Results will inform a better understanding of trial reporting on the follow-up, and handling of categories with potentially missing outcome data, an issue of importance for systematic reviewers and for standards of trial reporting.
Objectives: To describe characteristics, reporting and handling of categories of participants that could be potentially counted as having MPD in RCTs included in Cochrane and non-Cochrane systematic reviews (SRs).
Methods: We selected a random sample of 100 Cochrane and non-Cochrane SRs published in 2012. Eligible SRs reported a group-level meta-analysis of a patient-important dichotomous efficacy outcome, with a statistically significant effect estimate. Ten reviewers, working in pairs, independently extracted data from the RCTs included in eligible meta-analyses. We focused on 10 categories that could be potentially counted as MPD: 'participants deemed ineligible after randomization', 'did not receive any treatment', 'withdrew consent', 'outcome not assessable', 'explained and unexplained lost to follow-up', 'dead', 'experienced adverse events', 'non-compliant', 'discontinued prematurely', and 'cross-over'. We specifically assessed: 1) the number of participants in those categories; 2) whether trialists explicitly reported on the follow-up status of those participants; and 3) how trialists handled those participants in their analysis.
Results: We included a total of 672 RCTs included in 100 eligible Cochrane and non-Cochrane SRs. We are in the process of data abstraction. We will present the findings of the study at the Colloquium.
Conclusions: Results will inform a better understanding of trial reporting on the follow-up, and handling of categories with potentially missing outcome data, an issue of importance for systematic reviewers and for standards of trial reporting.