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Trials
Published in: Trials 1/2009

Open Access 01-12-2009 | Study protocol

LOST to follow-up Information in Trials (LOST-IT): a protocol on the potential impact

Authors: Elie A Akl, Matthias Briel, John J You, Francois Lamontagne, Azim Gangji, Tali Cukierman-Yaffe, Mohamad Alshurafa, Xin Sun, Kara A Nerenberg, Bradley C Johnston, Claudio Vera, Edward J Mills, Dirk Bassler, Arturo Salazar, Neera Bhatnagar, Jason W Busse, Zara Khalid, SD Walter, Deborah J Cook, Holger J Schünemann, Douglas G Altman, Gordon H Guyatt

Published in: Trials | Issue 1/2009

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Abstract

Background

Incomplete ascertainment of outcomes in randomized controlled trials (RCTs) is likely to bias final study results if reasons for unavailability of patient data are associated with the outcome of interest. The primary objective of this study is to assess the potential impact of loss to follow-up on the estimates of treatment effect. The secondary objectives are to describe, for published RCTs, (1) the reporting of loss to follow-up information, (2) the analytic methods used for handling loss to follow-up information, and (3) the extent of reported loss to follow-up.

Methods

We will conduct a systematic review of reports of RCTs recently published in five top general medical journals. Eligible RCTs will demonstrate statistically significant effect estimates with respect to primary outcomes that are patient-important and expressed as binary data. Teams of 2 reviewers will independently determine eligibility and extract relevant information from each eligible trial using standardized, pre-piloted forms. To assess the potential impact of loss to follow-up on the estimates of treatment effect we will, for varying assumptions about the outcomes of participants lost to follow-up (LTFU), calculate (1) the percentage of RCTs that lose statistical significance and (2) the mean change in effect estimate across RCTs. The different assumptions we will test are the following: (1) none of the LTFU participants had the event; (2) all LTFU participants had the event; (3) all LTFU participants in the treatment group had the event; none of those in the control group had it (worst case scenario); (4) the event incidence among LTFU participants (relative to observed participants) increased, with a higher relative increase in the intervention group; and (5) the event incidence among LTFU participants (relative to observed participants) increased in the intervention group and decreased in the control group.

Discussion

We aim to make our objectives and methods transparent. The results of this study may have important implications for both clinical trialists and users of the medical literature.
Appendix
Available only for authorised users
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Metadata
Title
LOST to follow-up Information in Trials (LOST-IT): a protocol on the potential impact
Authors
Elie A Akl
Matthias Briel
John J You
Francois Lamontagne
Azim Gangji
Tali Cukierman-Yaffe
Mohamad Alshurafa
Xin Sun
Kara A Nerenberg
Bradley C Johnston
Claudio Vera
Edward J Mills
Dirk Bassler
Arturo Salazar
Neera Bhatnagar
Jason W Busse
Zara Khalid
SD Walter
Deborah J Cook
Holger J Schünemann
Douglas G Altman
Gordon H Guyatt
Publication date
01-12-2009
Publisher
BioMed Central
Published in
Trials / Issue 1/2009
Electronic ISSN: 1745-6215
DOI
https://doi.org/10.1186/1745-6215-10-40

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