Reliability of monitoring the clinical dementia rating in multicenter clinical trials.
BACKGROUND
The Clinical Dementia Rating (CDR) is quickly becoming a criterion standard in multicenter clinical trials in Alzheimer disease. An abbreviated version, with formal monitoring for consistency across sites and raters, is currently used in the Alzheimer's Disease Cooperative Study (ADCS).


OBJECTIVE
To demonstrate the degree of agreement on CDR scoring of clinical monitors working independently from ADCS-CDR worksheets.


METHODS
Three members of the ADCS who are experienced and highly trained with respect to the CDR independently reviewed the ADCS-CDR worksheets of 15 subjects, assigning box and global CDR scores according to the prescribed algorithm.


METHODS
The ratings were assigned during a single, 3-hour session in a closed room.


METHODS
Two clinical monitors and one project director/clinical monitor supervisor.


METHODS
Percent agreement, Kendall's tau-b, and Cohen's kappa were used to assess the degree of agreement of the raters with the previously established gold standard assessment on global and box scores for the 15 subjects.


RESULTS
Raters, blinded to patient groupings, were in agreement with the Gold Standard global CDR assessment on 87% of ratings. Kappa values indicated good (kappa = 0.66, orientation and judgment & problem solving boxes) to excellent (kappa = 0.83, global CDR) agreement.


CONCLUSIONS
The ADCS-CDR worksheets were reliably and consistently scored by clinical monitors, who may be considered proxy gold standards for CDR assessment.
Schafer
Kimberly A
KA
Department of Neurosciences, University of California, San Diego, CA, USA.
Tractenberg
Rochelle E
RE
Sano
Mary
M
Mackell
Joan A
JA
Thomas
Ronald G
RG
Gamst
Anthony
A
Thal
Leon J
LJ
Morris
John C
JC
D002986:Clinical Trials as Topic; D003704:Dementia / Q000523:psychology*; D006801:Humans; D015337:Multicenter Studies as Topic; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D015203:Reproducibility of Results; D016037:Single-Blind Method