Mild cognitive impairment as predictor for Alzheimer's disease in clinical practice: effect of age and diagnostic criteria.
BACKGROUND
We investigated whether the predictive accuracy of mild cognitive impairment (MCI) for Alzheimer-type dementia (AD) in a clinical setting is dependent on age and the definition of MCI used.


METHODS
Non-demented subjects older than 40 (n=320) who attended a memory clinic of a university hospital were reassessed 5 years later for the presence of AD. MCI was diagnosed according to the criteria of amnestic MCI, mild functional impairment (MFI), ageing-associated cognitive decline (AACD), and age-associated memory impairment (AAMI). The main outcome measure was the area under the curve (AUC) of a receiver operating characteristic (ROC) curve. Analyses were conducted on the entire sample and on subgroups of subjects aged 40-54, 55-69 and 70-85 years.


RESULTS
A diagnosis of AD at follow-up was made in 58 subjects. Four of them were in the 40-54 age group, 29 in the 55-69 age group and 25 in the 70-85 age group. The diagnostic accuracy in the entire sample was low to moderately high with AUCs ranging from 0.56 (AACD) to 0.75 (amnestic MCI). A good predictive accuracy with an AUC >0.80 was only observed in subjects aged 70-85 using the criteria of amnestic MCI (AUC=0.84).


CONCLUSIONS
The predictive accuracy of MCI for AD is dependent on age and the definition of MCI used. The predictive accuracy is good only for amnestic MCI in subjects 70-85 years. As subjects with prodromal AD are often younger than 70, the usefulness of MCI as predictor of AD in clinical practice is limited.
Visser
P J
PJ
Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands. pj.visser@np.unimaas.nl
Verhey
F R J
FR
D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology; D000544:Alzheimer Disease / Q000453:epidemiology* / Q000523:psychology; D019540:Area Under Curve; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D008875:Middle Aged; D018579:Patient Selection; D011336:Probability; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D009626:Terminology as Topic