TY - JOUR
T1 - LOST to follow-up Information in Trials (LOST-IT)
T2 - A protocol on the potential impact
AU - Akl, Elie A.
AU - Briel, Matthias
AU - You, John J.
AU - Lamontagne, Francois
AU - Gangji, Azim
AU - Cukierman-Yaffe, Tali
AU - Alshurafa, Mohamad
AU - Sun, Xin
AU - Nerenberg, Kara A.
AU - Johnston, Bradley C.
AU - Vera, Claudio
AU - Mills, Edward J.
AU - Bassler, Dirk
AU - Salazar, Arturo
AU - Bhatnagar, Neera
AU - Busse, Jason W.
AU - Khalid, Zara
AU - Walter, S. D.
AU - Cook, Deborah J.
AU - Schünemann, Holger J.
AU - Altman, Douglas G.
AU - Guyatt, Gordon H.
N1 - Funding Information:
We thank Ann Grifasi, Deborah Maddock Shelley Anderson and Monica Owen for their administrative assistance. We thank Aravin Duraik for developing the study electronic forms. Pfizer Inc is funding this study. The funder had no role in the study design, in the writing of the manuscript, or in the decision to submit this or future manuscripts for publication. Matthias Briel is supported by a scholarship for advanced researchers from the Swiss National Foundation (PASMA-112951/1). John You is supported by a Career Scientist Award from the Ontario Ministry of Health and Long-Term Care. Xin Sun is supported by two research scholarships from the National Natural Science Foundation of China (70503021, 70703025). Kara Nerenberg is supported by a RCT Mentorship Award from the Canadian Institutes of Health Research (CIHR). Bradley Johnston is supported by a Duncan L. Gordon Fellowship from SickKids Foundation. Jason Busse is funded by a New Investigator Award from the CIHR and Canadian Chiro- practic Research Foundation. Deborah Cook is a Research Chair of the CIHR. Douglas Altman is supported by Cancer Research UK.
PY - 2009/6/11
Y1 - 2009/6/11
N2 - 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.
AB - 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.
UR - https://www.scopus.com/pages/publications/67651046982
U2 - 10.1186/1745-6215-10-40
DO - 10.1186/1745-6215-10-40
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C2 - 19519891
AN - SCOPUS:67651046982
SN - 1745-6215
VL - 10
JO - Trials
JF - Trials
M1 - 40
ER -