, Volume 15, Issue 2, pp 141–155 | Cite as

Determining Clinically Important Differences in Health Status Measures

A General Approach with Illustration to the Health Utilities Index Mark II
  • Greg SamsaEmail author
  • David Edelman
  • Margaret L. Rothman
  • G. Rhys Williams
  • Joseph Lipscomb
  • David Matchar
Leading Article Determining Clinical Differences in Health Status


The objective of this article was to describe and illustrate a comprehensive approach for estimating clinically important differences (CIDs) in health-related quality-of-life (HR-QOL). A literature review and pilot study were conducted to determine whether effect size-based benchmarks are consistent with CIDs obtained from other approaches.

CIDs may be estimated based primarily upon effect sizes, supplemented by more traditional anchor-based methods of benchmarking (i.e. direct, cross-sectional or longitudinal approaches). A literature review of articles discussing CIDs provided comparative data on effect sizes for various chronic conditions. A pilot study was then conducted to estimate the minimum CID of the Health Utilities Index (HUI) Mark II, and to compare the observed between-group differences observed in a recent randomised trial of an acute stroke intervention with this benchmark.

The use of standardised effect size benchmarks has a number of advantages–for example, effect sizes are efficient, widely accepted outside HR-QOL, and have well accepted benchmarks based upon external anchors. In addition, our literature review and pilot study suggest that effect size-based CID benchmarks are similar to those which would be obtained using more traditional methods. For most HR-QOL instruments, we do not know the changes in score which constitute CIDs of various magnitudes. This makes interpretation of HR-QOL results from clinical trials difficult, and having a benchmarking process which is relatively straightforward would be highly desirable.


Adis International Limited Physical Component Summary Health Utility Index Health Utility Index Mark Sickness Impact Profile 
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Copyright information

© Adis International Limited 1999

Authors and Affiliations

  • Greg Samsa
    • 1
    • 2
    • 3
    Email author
  • David Edelman
    • 1
    • 2
    • 4
  • Margaret L. Rothman
    • 5
  • G. Rhys Williams
    • 5
  • Joseph Lipscomb
    • 1
    • 3
    • 6
  • David Matchar
    • 1
    • 2
    • 4
  1. 1.Center for Clinical Health Policy ResearchDuke UniversityDurhamUSA
  2. 2.Department of MedicineDuke University School of MedicineDurhamUSA
  3. 3.Department of Community and Family MedicineDuke University School of MedicineDurhamUSA
  4. 4.Center for Health Services Research in Primary CareDepartment of Veterans Affairs Medical CenterDurhamUSA
  5. 5.Janssen Research FoundationTitusvilleUSA
  6. 6.Sanford Institute for Public PolicyDuke UniversityDurhamUSA

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