Cited by 396Statistical Methods in Clinical TrialsMeta-analysis and systematic reviewsStatistical Methods and Bayesian Inference

Handling missing data in RCTs; a review of the top medical journals

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Bell, Melanie L, Fiero, Mallorie, Horton, Nicholas J, Hsu, Chiu-Hsieh·2014·BMC Medical Research Methodology

Abstract

BACKGROUND: Missing outcome data is a threat to the validity of treatment effect estimates in randomized controlled trials. We aimed to evaluate the extent, handling, and sensitivity analysis of missing data and intention-to-treat (ITT) analysis of randomized controlled trials (RCTs) in top tier medical journals, and compare our findings with previous reviews related to missing data and ITT in RCTs. METHODS: Review of RCTs published between July and December 2013 in the BMJ, JAMA, Lancet, and New England Journal of Medicine, excluding cluster randomized trials and trials whose primary outcome was survival. RESULTS: Of the 77 identified eligible articles, 73 (95%) reported some missing outcome data. The median percentage of participants with a missing outcome was 9% (range 0 - 70%). The most commonly used method to handle missing data in the primary analysis was complete case analysis (33, 45%), while 20 (27%) performed simple imputation, 15 (19%) used model based methods, and 6 (8%) used multiple imputation. 27 (35%) trials with missing data reported a sensitivity analysis. However, most did not alter the assumptions of missing data from the primary analysis. Reports of ITT or modified ITT were found in 52 (85%) trials, with 21 (40%) of them including all randomized participants. A comparison to a review of trials reported in 2001 showed that missing data rates and approaches are similar, but the use of the term ITT has increased, as has the report of sensitivity analysis. CONCLUSIONS: Missing outcome data continues to be a common problem in RCTs. Definitions of the ITT approach remain inconsistent across trials. A large gap is apparent between statistical methods research related to missing data and use of these methods in application settings, including RCTs in top medical journals.

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  1. [7]Council NR The prevention and treatment of missing data in clinical trials Committee on National Statistics, Division of Behavioral and Social Sciences and Education 2010 Washington DC National Academies Press 24983040
  2. The pre-publication history for this paper can be accessed here: http://www.biomedcentral.com/1471-2288/14/118/prepub

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Authors
Bell, M. L., Fiero, M., Horton, N. J., & Hsu, C.-H.
Affiliations
  • University of Arizona (US)
  • Amherst College (US)
Corresponding author
Bell, Melanie L
Venue
BMC Medical Research Methodology
Published
2014-11-19
Volume
14
Issue
1
Pages
118-118
ISSN
1471-2288 (ISSN-L)
OpenAlex
W2085508623
Cited by
395
References
30
Citations by year
2026: 28 · 2025: 42 · 2024: 39 · 2023: 46 · 2022: 44 · 2021: 51 · 2020: 34 · 2019: 34 · 2018: 26 · 2017: 25 · 2016: 17 · 2015: 9
FWCI
17.95
Type
journal article
Language
en
Open access
Locations
  • BMC Medical Research Methodology (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • UA Campus Repository (The University of Arizona) (acceptedVersion, cc-by)
Topics
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Clinical Trials
  • Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods and Bayesian Inference
Keywords
missing data, randomized controlled trials, intention-to-treat analysis, sensitivity analysis, complete case analysis, multiple imputation, missing data handling, reporting practices, medical journals
MeSH terms
Humans, Publishing, Research Design, Randomized Controlled Trials as Topic, Treatment Outcome, Intention to Treat Analysis

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