Validation of the new interpretive guidelines for the clinical dementia rating scale sum of boxes score in the national Alzheimer's coordinating center database.
BACKGROUND
It was recently demonstrated that the Clinical Dementia Rating scale Sum of Boxes (CDR-SB) score can be used to accurately stage severity of Alzheimer dementia and mild cognitive impairment (MCI). However, to our knowledge, the utility of those interpretive guidelines has not been cross-validated or applied to a heterogeneous sample of dementia cases.


OBJECTIVE
To cross-validate the staging guidelines proposed in a previous study using the National Alzheimer's Coordinating Center (NACC) database.


METHODS
The previously published cut scores were applied to the NACC sample and diagnostic accuracy estimates obtained. Next, analyses were restricted to NACC participants with a CDR global score (CDR-GS) of 0.5 and receiver operating characteristic curves generated to determine optimal CDR-SB cut scores for distinguishing MCI from very early dementia.


METHODS
The 2008 NACC uniform data set.


METHODS
There were 12 462 participants (5115 controls; 2551 patients with MCI; 4796 patients with dementia, all etiologies) in the NACC data set used for the current analysis. Main Outcome Measure Accurate prediction of diagnoses (MCI or dementia) using the CDR-SB score.


RESULTS
The previously proposed CDR-SB ranges successfully classified the vast majority of patients across all impairment ranges with a kappa of 0.91 and 94% overall correct classification rate. Additionally, the CDR-SB score discriminated between patients diagnosed with MCI and dementia when CDR-GS was restricted to 0.5 (overall area under the curve = 0.83).


CONCLUSIONS
These findings cross-validate the previously published CDR-SB interpretative guidelines for staging dementia severity and extend those findings to a large heterogeneous sample of patients with dementia. Additionally, the CDR-SB scores distinguished MCI from dementia in patients with reasonable accuracy when CDR-GS was restricted to 0.5.
O'Bryant
Sid E
SE
F. Marie Hall Institute for Rural and Community Health, Texas Tech University Health Science Center, 3601 4th St, STOP 6232, Lubbock, TX 79430, USA. sid.obryant@ttuhsc.edu
Lacritz
Laura H
LH
Hall
James
J
Waring
Stephen C
SC
Chan
Wenyaw
W
Khodr
Zeina G
ZG
Massman
Paul J
PJ
Hobson
Valerie
V
Cullum
C Munro
CM
D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000175:diagnosis / Q000523:psychology; D003627:Data Interpretation, Statistical; D003704:Dementia / Q000145:classification / Q000175:diagnosis* / Q000523:psychology*; D005260:Female; D017408:Guidelines as Topic / Q000592:standards*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013223:Statistics as Topic / Q000379:methods / Q000592:standards*