Background
The utility of combining early markers to predict conversion from mild cognitive impairment
(MCI) to Alzheimer's Disease (AD) remains uncertain.
Methods
Included in the study were 148 outpatients with MCI, broadly defined, followed at
6-month intervals. Hypothesized baseline predictors for follow-up conversion to AD
(entire sample: 39/148 converters) were cognitive test performance, informant report
of functional impairment, apolipoprotein E genotype, olfactory identification deficit,
and magnetic resonance imaging (MRI) hippocampal and entorhinal cortex volumes.
Results
In the 3-year follow-up patient sample (33/126 converters), five of eight hypothesized
predictors were selected by backward and stepwise logistic regression: Pfeffer Functional
Activities Questionnaire (FAQ; informant report of functioning), University of Pennsylvania
Smell Identification Test (UPSIT; olfactory identification), Selective Reminding Test
(SRT) immediate recall (verbal memory), MRI hippocampal volume, and MRI entorhinal
cortex volume. For 10% false positives (90% specificity), this five-predictor combination
showed 85.2% sensitivity, combining age and Mini-Mental State Examination (MMSE) showed
39.4% sensitivity; combining age, MMSE, and the three clinical predictors (SRT immediate
recall, FAQ, and UPSIT) showed 81.3% sensitivity. Area under ROC curve was greater
for the five-predictor combination (.948) than age plus MMSE (.821; p = .0009) and remained high in subsamples with MMSE ≥ 27/30 and amnestic MCI.
Conclusions
The five-predictor combination strongly predicted conversion to AD and was markedly
superior to combining age and MMSE. Combining the clinically administered measures
also led to strong predictive accuracy. If independently replicated, the findings
have potential utility for early detection of AD.
Key Words
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Article info
Publication history
Published online: August 26, 2008
Accepted:
June 29,
2008
Received in revised form:
June 24,
2008
Received:
May 8,
2008
Identification
Copyright
© 2008 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.
