Cited by 398Statistical Methods and Bayesian InferenceStatistical Methods in Clinical TrialsAdvanced Causal Inference Techniques

ACCOUNTING FOR DROPOUT BIAS USING MIXED-EFFECTS MODELS

Mallinckrodt, Craig H., Clark, W. Scott, David, Stacy R.·2001·Journal of Biopharmaceutical Statistics

Abstract

Treatment effects are often evaluated by comparing change over time in outcome measures. However, valid analyses of longitudinal data can be problematic when subjects discontinue (dropout) prior to completing the study. This study assessed the merits of likelihood-based repeated measures analyses (MMRM) compared with fixed-effects analysis of variance where missing values were imputed using the last observation carried forward approach (LOCF) in accounting for dropout bias. Comparisons were made in simulated data and in data from a randomized clinical trial. Subject dropout was introduced in the simulated data to generate ignorable and nonignorable missingness. Estimates of treatment group differences in mean change from baseline to endpoint from MMRM were, on average, markedly closer to the true value than estimates from LOCF in every scenario simulated. Standard errors and confidence intervals from MMRM accurately reflected the uncertainty of the estimates, whereas standard errors and confidence intervals from LOCF underestimated uncertainty.

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Crossref · 10.1081/bip-100104194

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Authors
Mallinckrodt, C. H., Clark, W. S., & David, S. R.
Affiliations
Eli Lilly (United States) (US)
Venue
Journal of Biopharmaceutical Statistics
Published
2001-01-01
Volume
11
Issue
1-2
Pages
9-21
ISSN
  • 1054-3406 (ISSN-L)
  • 1520-5711
OpenAlex
W2073155558
Cited by
398
References
14
Citations by year
2026: 12 · 2025: 13 · 2024: 21 · 2023: 12 · 2022: 27 · 2021: 19 · 2020: 20 · 2019: 13 · 2018: 14 · 2017: 14 · 2016: 18 · 2015: 21 · 2014: 16 · 2013: 23 · 2012: 19
FWCI
11.96
Type
journal article
Language
en
Open access
closed
Locations
  • Journal of Biopharmaceutical Statistics (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods and Bayesian Inference
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Clinical Trials
  • Physical Sciences › Mathematics › Statistics and Probability › Advanced Causal Inference Techniques
Keywords
mixed models, last observation carried forward, missing data, non-ignorable missingness, treatment effect estimation, longitudinal data, randomized controlled trials, standard error estimation
MeSH terms
Analysis of Variance, Humans, Longitudinal Studies, Patient Dropouts, Models, Statistical, Bias, Confidence Intervals, Randomized Controlled Trials as Topic

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