Impact of missing participant data for dichotomous outcomes on pooled effect estimates in systematic reviews: A protocol for a methodological study

Background: There is no consensus on how authors conducting meta-analysis should deal with trial participants with missing outcome data. The objectives of this study are to assess in Cochrane and non-Cochrane systematic reviews: (1) which categories of trial participants the systematic review author...

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Bibliographic Details
Authors: Akl E.A., Kahale L.A., Agarwal A., Al-Matari N., Ebrahim S., Alexander P.E., Briel M., Brignardello-Petersen R., Busse J.W., Diab B., Iorio A., Kwong J., Li L., Lopes L.C., Mustafa R., Neumann I., Tikkinen K.A.O., Vandvik P.O., Zhang Y., Alonso-Coello P., Guyatt G.
Format: article
Status:Published version
Publication Date:2014
Country:España
Institution:Institut d’Investigació Biomèdica Sant Pau (IIB Sant Pau)
Repository:r-IIB SANT PAU. Repositorio Institucional de Producción Científica del Instituto de Investigación Biomédica Sant Pau
OAI Identifier:oai:iibsantpau.fundanetsuite.com:p10648
Online Access:https://iibsantpau.fundanetsuite.com/Publicaciones/ProdCientif/PublicacionFrw.aspx?id=10648
https://www.scopus.com/inward/record.uri?eid=2-s2.0-84927950888&doi=10.1186%2f2046-4053-3-137&partnerID=40&md5=0440b43eeeec4a4e9390ada43189f2b8
Access Level:Open access
Keyword:Article
bivariate analysis
data analysis
human
intention to treat analysis
meta analysis (topic)
methodology
outcome assessment
outcomes research
priority journal
randomized controlled trial (topic)
sample size
sensitivity analysis
statistical bias
systematic review (topic)
literature
Bias (Epidemiology)
Meta-Analysis as Topic
Review Literature as Topic
Description
Summary:Background: There is no consensus on how authors conducting meta-analysis should deal with trial participants with missing outcome data. The objectives of this study are to assess in Cochrane and non-Cochrane systematic reviews: (1) which categories of trial participants the systematic review authors consider as having missing participant data (MPD), (2) how trialists reported on participants with missing outcome data in trials, (3) whether systematic reviewer authors actually dealt with MPD in their meta-analyses of dichotomous outcomes consistently with their reported methods, and (4) the impact of different methods of dealing with MPD on pooled effect estimates in meta-analyses of dichotomous outcomes. Methods/Design: We will conduct a methodological study of Cochrane and non-Cochrane systematic reviews. Eligible systematic reviews will include a group-level meta-analysis of a patient-important dichotomous efficacy outcome, with a statistically significant effect estimate. Teams of two reviewers will determine eligibility and subsequently extract information from each eligible systematic review in duplicate and independently, using standardized, pre-piloted forms. The teams will then use a similar process to extract information from the trials included in the meta-analyses of interest. We will assess first which categories of trial participants the systematic reviewers consider as having MPD. Second, we will assess how trialists reported on participants with missing outcome data in trials. Third, we will compare what systematic reviewers report having done, and what they actually did, in dealing with MPD in their meta-analysis. Fourth, we will conduct imputation studies to assess the effects of different methods of dealing with MPD on the pooled effect estimates of meta-analyses. We will specifically calculate for each method (1) the percentage of systematic reviews that lose statistical significance and (2) the mean change of effect estimates across systematic reviews. Discussion: The impact of different methods of dealing with MPD on pooled effect estimates will help judge the associated risk of bias in systematic reviews. Our findings will inform recommendations regarding what assumptions for MPD should be used to test the robustness of meta-analytical results. © 2014 Akl et al.