Attrition and non-compliance in secondary stroke prevention trials

E. Gencheva*, M. Sloan, S. Leurgans, R. Raman, Y. Harris, P. Gorelick

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

27 Scopus citations


Background: Attrition and non-compliance of subjects in secondary stroke prevention trials due to study drug-induced adverse events and loss to follow-up could lead to bias and loss of information, thus affecting the analysis of study results. Methods: We reviewed results from ten antiplatelet stroke prevention clinical trials: CAN TIA, DUTCH TIA, SWED ASA, SALT, UK TIA, CATS, TASS, ESPS, ESPS-2, and CAPRIE to tabulate the frequencies for total subject discontinuation, voluntary withdrawal, and loss to follow-up. Results: Forty thousand seven hundred and thirty (40,730) subjects participated in the aforementioned secondary stroke prevention trials. The range of outcomes was 11.8-52.0% for subjects discontinued for any reason (n = 9 trials); 3.0-20.9% for study drug-induced adverse events (n = 9 trials), and 4.2-7.8% for voluntary withdrawal (n = 10 trials). Conclusion: There is a substantial discrepancy (up to 20%) between the frequencies of total subject discontinuation for any reason and the sum of study drug-induced adverse events, voluntary withdrawal and loss to follow-up. Underestimation of these important outcomes may limit the ability of clinicians to translate results from clinical trials into medical practice.

Original languageEnglish (US)
Pages (from-to)61-66
Number of pages6
Issue number1-2
StatePublished - 2004


  • Attrition rate
  • Clinical trials
  • Lost to follow-up
  • Withdrawal

ASJC Scopus subject areas

  • Clinical Neurology
  • Epidemiology


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