Rate of progression of mild cognitive impairment to dementia--meta-analysis of 41 robust inception cohort studies.
OBJECTIVE
To quantify the risk of developing dementia in those with mild cognitive impairment (MCI).


METHODS
Meta-analysis of inception cohort studies.


RESULTS
Forty-one robust cohort studies were identified. To avoid heterogeneity clinical studies, population studies and clinical trials were analysed separately. Using Mayo defined MCI at baseline and adjusting for sample size, the cumulative proportion who progressed to dementia, to Alzheimer's disease (AD) and to vascular dementia (VaD) was 39.2%, 33.6% and 6.2%, respectively in specialist settings and 21.9%, 28.9% and 5.2%, respectively in population studies. The adjusted annual conversion rate (ACR) from Mayo defined MCI to dementia, AD and VaD was 9.6%, 8.1% and 1.9%, respectively in specialist clinical settings and 4.9%, 6.8% and 1.6% in community studies. Figures from non-Mayo defined MCI and clinical trials are also reported.


CONCLUSIONS
The ACR is approximately 5-10% and most people with MCI will not progress to dementia even after 10 years of follow-up.
Mitchell
A J
AJ
Liaison Psychiatry, Leicester Partnership Trust and University of Leicester, Leicester, UK. alex.mitchell@leicspart.nhs.uk
Shiri-Feshki
M
M
D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis / Q000453:epidemiology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D015331:Cohort Studies; D003704:Dementia / Q000175:diagnosis* / Q000453:epidemiology*; D015140:Dementia, Vascular / Q000175:diagnosis / Q000453:epidemiology; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009483:Neuropsychological Tests; D015995:Prevalence; D012720:Severity of Illness Index