Research Article

The ADAS-cog and clinically meaningful change in the VISTA clinical trial of galantamine for Alzheimer's disease†

  1. Kenneth Rockwood1,2,*,
  2. Sherri Fay1,
  3. Mary Gorman3

Article first published online: 22 JUN 2009

DOI: 10.1002/gps.2319

Issue

International Journal of Geriatric Psychiatry

International Journal of Geriatric Psychiatry

Volume 25, Issue 2, pages 191–201, February 2010

Additional Information

How to Cite

Rockwood, K., Fay, S. and Gorman, M. (2010), The ADAS-cog and clinically meaningful change in the VISTA clinical trial of galantamine for Alzheimer's disease. International Journal of Geriatric Psychiatry, 25: 191–201. doi: 10.1002/gps.2319

Author Information

  1. 1

    Division of Geriatric Medicine, Capital District Health Authority, Dalhousie University, Halifax, NS, Canada

  2. 2

    Geriatric Medicine Research Unit, Capital District Health Authority, Dalhousie University, Halifax, NS, Canada

  3. 3

    St. Martha's Hospital, Antigonish, NS, Canada

*Division of Geriatric Medicine, Dalhousie University, 1421-5955 Veterans' Memorial Lane, Halifax, NS, B3H 2E1 Canada.

  1. †

    Kenneth Rockwood has received ad hoc consulting or speaker honoraria from Janssen-Ortho, the study's co-sponsor, Glaxo Smith Kline, Lundbeck, Merck, Myriad, Novartis, Numico, Pfizer and Shire. He has no stock ownership in pharmaceutical companies. He also established DementiaGuide Inc., which promotes symptom-based assessments of the response to treatment for dementia. Sherri Fay and Mary Gorman declare no competing interests.

Publication History

  1. Issue published online: 18 JAN 2010
  2. Article first published online: 22 JUN 2009
  3. Manuscript Accepted: 20 APR 2009
  4. Manuscript Received: 24 JUN 2008

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Keywords:

  • Alzheimer's disease;
  • ADAS-cog;
  • clinical meaningfulness;
  • judgement-based measures;
  • VISTA

Abstract

Background

A minimum 4-point change at 6 months on the Alzheimer's disease assessment scale-cognitive subscale (ADAS-cog) is deemed clinically important, but this cut-point has been little studied in relation to clinical meaningfulness. In an investigator-initiated, clinical trial of galantamine, we investigated the extent to which a 4-point change classifies goal attainment by individual patients.

Methods

Secondary analysis of the video imaging synthesis of treating Alzheimer's disease (VISTA) study: a 4-month, multi-centre, parallel-group, double-blind, placebo-controlled, trial of galantamine in 130 mild-moderate Alzheimer's disease patients (4-month open-label follow-up). ADAS-cog responses at 6 months were compared with outcomes on three clinical measures: clinician's interview based impression of change-plus caregiver input (CIBIC+), patient/carer-goal attainment scaling (PGAS) and clinician-GAS (CGAS).

Results

Thirty-seven of 99 patients improved by ≥ 4 points on the ADAS-cog at 6 months, and 16/99 showed ≥ 4-point worsening. ADAS-cog change scores correlated notionally to modestly with changes on the CGAS (r = −0.31), the PGAS (r = −0.29) and the CIBIC+ (r = 0.31). As a group, patients with ADAS-cog improvement were significantly more likely to improve on the clinical measures; those who worsened showed non-significant clinical decline. Individually, about half were misclassified in relation to each clinical measure; often when the ADAS-Cog detected ‘no change’, clinically meaningful effects could be detected. Even so, no ADAS-Cog cut-point optimally classified patients' clinical responses.

Conclusion

A 4-point ADAS-cog change at 6 months is clinically meaningful for groups. Substantial individual misclassification between the ADAS-cog and clinical measures suggests no inherent meaning to a 4-point ADAS-cog change for a given patient. Copyright © 2009 John Wiley & Sons, Ltd.

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