Higher risk of progression to dementia in mild cognitive impairment cases who revert to normal

Neurology. 2014 Jan 28;82(4):317-25. doi: 10.1212/WNL.0000000000000055. Epub 2013 Dec 18.

Abstract

Objective: To estimate rates of progression from mild cognitive impairment (MCI) to dementia and of reversion from MCI to being cognitively normal (CN) in a population-based cohort.

Methods: Participants (n = 534, aged 70 years and older) enrolled in the prospective Mayo Clinic Study of Aging were evaluated at baseline and every 15 months to identify incident MCI or dementia.

Results: Over a median follow-up of 5.1 years, 153 of 534 participants (28.7%) with prevalent or incident MCI progressed to dementia (71.3 per 1,000 person-years). The cumulative incidence of dementia was 5.4% at 1 year, 16.1% at 2, 23.4% at 3, 31.1% at 4, and 42.5% at 5 years. The risk of dementia was elevated in MCI cases (hazard ratio [HR] 23.2, p < 0.001) compared with CN subjects. Thirty-eight percent (n = 201) of MCI participants reverted to CN (175.0/1,000 person-years), but 65% subsequently developed MCI or dementia; the HR was 6.6 (p < 0.001) compared with CN subjects. The risk of reversion was reduced in subjects with an APOE ε4 allele (HR 0.53, p < 0.001), higher Clinical Dementia Rating Scale-Sum of Boxes (HR 0.56, p < 0.001), and poorer cognitive function (HR 0.56, p < 0.001). The risk was also reduced in subjects with amnestic MCI (HR 0.70, p = 0.02) and multidomain MCI (HR 0.61, p = 0.003).

Conclusions: MCI cases, including those who revert to CN, have a high risk of progressing to dementia. This suggests that diagnosis of MCI at any time has prognostic value.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Age Factors
  • Aged
  • Aged, 80 and over
  • Apolipoproteins E / genetics
  • Cognitive Dysfunction / epidemiology*
  • Cognitive Dysfunction / physiopathology*
  • Cohort Studies
  • Community Health Planning
  • Dementia / diagnosis
  • Dementia / epidemiology*
  • Disease Progression
  • Female
  • Humans
  • Male
  • Neuropsychological Tests
  • Predictive Value of Tests
  • Proportional Hazards Models
  • Psychiatric Status Rating Scales
  • Risk Factors

Substances

  • Apolipoproteins E