Assessing the impact of attrition in randomized controlled trials

Catherine E Hewitt, Bharathy Kumaravel, Jo C Dumville, David J Torgerson, Trial attrition study group

Research output: Contribution to journalArticlepeer-review

Abstract

A survey of randomized controlled trials found that almost a quarter of trials had more than 10% of responses missing for the primary outcome. There are a number of ways in which data could be missing: the subject is unable to provide it, or they withdraw, or become lost to follow-up. Such attrition means that balance in baseline characteristics for those randomized may not be maintained in the subsample who has outcome data. For individual trials, if the attrition is systematic and linked to outcome, then this will result in biased estimates of the overall effect. It then follows that if such trials are combined in a meta-analysis, it will result in a biased estimate of the overall effect and be misleading. The aim of this study was to investigate the impact of attrition on baseline imbalance within individual trials and across multiple trials.
Original languageEnglish
Pages (from-to)1264-1270
Number of pages7
JournalJournal of Clinical Epidemiology
Volume63
Issue number11
DOIs
Publication statusPublished - Nov 2010

Keywords

  • Bias (Epidemiology)
  • Data Collection
  • Humans
  • Meta-Analysis as Topic
  • Musculoskeletal Diseases
  • Patient Dropouts
  • Randomized Controlled Trials as Topic

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