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Informative noncompliance in endpoint trials

Steven M Snapinn1, Qi Jiang, Boris Iglewicz

  • 1Steven Snapinn, Amgen, One Amgen Center Drive 24-2-C, Thousand Oaks CA 91320 USA. ssnapinn@amgen.com

Current Controlled Trials in Cardiovascular Medicine
|July 6, 2004
PubMed

Insights

Noncompliance with study medications can reduce clinical trial power. This study shows noncompliance is often informative, impacting study power and sample size calculations in endpoint clinical trials.

Area of Science:

  • Clinical Trials
  • Biostatistics
  • Pharmacoeconomics

Background:

  • Noncompliance with study medications is a significant challenge in endpoint clinical trials.
  • Including noncompliant patient data in intention-to-treat analyses can decrease statistical power.

Purpose of the Study:

  • To investigate the assumption of noninformative noncompliance in clinical trial sample size calculations.
  • To demonstrate the effect of informative noncompliance on statistical power and sample size.

Main Methods:

  • Analysis of data from multiple published clinical trials (OPTIMAAL, LIFE, RENAAL, SOLVD-Prevention, SOLVD-Treatment).
  • Evaluation of the relationship between medication noncompliance and study endpoint risk.

Main Results:

  • The assumption that noncompliance is noninformative (independent of endpoint risk) is frequently violated.
  • Informative noncompliance can substantially affect statistical power and required sample size.

Conclusions:

  • Standard sample size calculations may be inadequate due to informative noncompliance.
  • Clinical trial design must account for the potential impact of informative noncompliance on study power and resource allocation.

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