Vascular subcortical hyperintensities predict conversion to vascular and mixed dementia in MCI patients.
OBJECTIVE
Patients with mild cognitive impairment (MCI) have an increased risk of dementia. The identification of predictors of conversion to dementia is therefore important. The aim of our study was to test the hypothesis that subcortical hyperintensities (SH) are associated with an increased rate of conversion to dementia in MCI patients.


METHODS
This was an observational study on consecutive MCI patients attending a memory clinic. We assessed SH on a baseline MRI scan, using a semiquantitative rating scale. A multivariable Cox regression model was used to test the association of SH with conversion to dementia.


RESULTS
We included 170 MCI patients. The median duration of follow-up was 3.8 years. During this period, 67 patients (39.4%, 95% CI: 32.1 to 46.8%) developed dementia: Alzheimer disease (AD) in 29 patients, dementia with Lewy bodies in 19, mixed dementia in 8, vascular dementia in 7, fronto-temporal dementia in 2, and primary progressive aphasia in 2. SH were not associated with the risk to develop dementia as a whole, including AD. However, the risk to develop vascular or mixed dementia increased significantly with increasing amounts of SH at baseline (HR=1.14 [95% CI: 1.06 to 1.24]), especially periventricular hyperintensities (HR=2.71 [95% CI: 1.60 to 4.58]), independently of medial temporal lobe atrophy, age, gender, vascular risk factors, education, and cognitive functions at baseline.


CONCLUSIONS
The risk of vascular or mixed dementia, but not of other types of dementia, was significantly increased in MCI patients with a large amount of subcortical hyperintensities at baseline.
Bombois
Stéphanie
S
Department of Neurology, EA 2691, Memory Center, University Hospital 59037 Lille, France.
Debette
Stéphanie
S
Bruandet
Amélie
A
Delbeuck
Xavier
X
Delmaire
Christine
C
Leys
Didier
D
Pasquier
Florence
F
D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000002:abnormalities / Q000473:pathology*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000473:pathology*; D015140:Dementia, Vascular / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008568:Memory; D008875:Middle Aged; D009483:Neuropsychological Tests; D016016:Proportional Hazards Models; D012307:Risk Factors; D013997:Time Factors