Interpreting the clinical significance of capacity scores for informed consent in Alzheimer disease clinical trials.

Full Abstract

OBJECTIVE:
Among Alzheimer disease (AD) patients enrolled in a clinical trial, the authors assessed the ability of a standardized capacity assessment procedure to identify persons who are capable of giving their own informed consent.

DESIGN:
Cross-sectional interview.

SETTING:
Thirteen sites participating in a randomized and placebo controlled study of simvastatin for the treatment of mild to moderate AD.

PARTICIPANTS:
Persons with mild to moderate AD and their study partners enrolled in the simvastatin clinical trial.

MEASUREMENTS:
Interviews to assess decision-making capacity using the MacArthur Competency Assessment Tool for Clinical Research (MacCAT-CR).

RESULTS:
Judges blinded to the subject's clinical status had a high rate of agreement on patients capable of giving their own informed consent (kappa = 0.73). The understanding subscale had the best receiver operator characteristic and an analysis of positive and negative predictive values over a range of hypothetical prevalences of incapacity to consent demonstrated the value of a range of understanding cut-points.

CONCLUSION:
Among mild to moderate AD patients, enrolled in an actual clinical trial, these results suggest evidence based guidelines for using the MacCAT-CR understanding subscale to help guide judgments about whether a patient has the capacity to consent.

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Author information

Author/s: Karlawish, Jason (J); Kim, Scott Y H (SY); Knopman, David (D); van Dyck, Christopher H (CH); James, Bryan D (BD); Marson, Daniel (D);

Affiliation: Department of Medicine, Alzheimer's Disease Center, Leonard Davis Institute for Health Economics, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, School of Medicine, PA, USA. Jason.karlawish(-atsign-)uphs.upenn.edu

Grants: T32 AG00247 (Agency:United States NIA) ; U01-AG10483 (Agency:United States NIA)

Journal and publication information

Publication Type: Comparative Study; Evaluation Studies; Journal Article; Multicenter Study; Research Support, N.I.H., Extramural

Journal: The American journal of geriatric psychiatry : official journal of the American Association for Geriatric Psychiatry (Am J Geriatr Psychiatry), published in United States. (Language: eng)

Reference: 2008-Jul; vol 16 (issue 7) : pp 568-74

Dates: Created 2008/07/02; Completed 2008/08/28;

PMID: 18556397, status: MEDLINE (last retrieval date: 11/6/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Mental Competency
Observer Variation
ROC Curve
Randomized Controlled Trials as Topic
Research Subjects - psychology
Sensitivity and Specificity
Single-Blind Method

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