title: Rate of conversion from prodromal Alzheimer's disease to Alzheimer's dementia: a systematic review of the literature.
abstract: BACKGROUND
  The purpose of this study was to summarize published estimates for conversion from mild cognitive impairment or amnestic mild cognitive impairment to Alzheimer's dementia. We carried out a systematic review of English language publications to identify cohort studies published since January 2006 that reported the risk or rate of conversion.
  
  
  CONCLUSIONS
  Thirty-two cohort studies were identified, of which 14 reported annualized conversion rates (ACRs). Conversions over 1 year ranged from 10.2 to 33.6% (5 studies, median: 19.0%), and over 2 years from 9.8 to 36.3% (7 studies, median: 18.6%). ACRs ranged from 7.5 to 16.5% (7 studies, median: 11.0%) per person-year for studies recruiting from clinics, and from 5.4 to 11.5% (7 studies, median: 7.1%) for community samples.
  
  
  CONCLUSIONS
  Extensive variation was observed in conversion rates due to the population sampled, diagnostic criteria, and duration, and because many studies did not account for loss to follow-up.
authors.affiliation: United BioSource Corporation, Lexington, Mass., USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Ward
authors.forename: Sarah
authors.initials: S
authors.lastname: Tardiff
authors.forename: Catherine
authors.initials: C
authors.lastname: Dye
authors.forename: H Michael
authors.initials: HM
authors.lastname: Arrighi
keywords: Alzheimer's dementia; Alzheimer's disease; Cognitive function; Meta-analysis; Mild cognitive impairment