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. Summary: 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. Key Message: 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.

Quantitative MRI of Perivascular Spaces at 3T for Early Diagnosis of Mild Cognitive Impairment

“…31,32 Anywhere from 32 to 38% of people with MCI progress to AD in 5 years or longer. 32,33 Annual rates of progression have been estimated to be 10 to 15%. 9–12 These findings have naturally generated an interest in using disease modifying agents to not only preserve cognitive function in MCI individuals but also slow their conversion to dementia.…”

Clinical practice guidelines for dementia in Australia

“…This recommendation was formulated based on an existing systematic review which found that, in a clinic setting, the annual conversion rate of mild cognitive impairment to Alzheimer disease was close to 10%. 12 At the time of diagnosis of dementia, and at regular intervals subsequently, assessment should be made for medical comorbidities and key psychiatric features associated with dementia, including depression, to ensure optimal management of coexisting conditions.…”

Eye Movements in Alzheimer's Disease

“…MCI is characterized by cognitive decline that exceeds the expected decline from aging, but does not greatly impact independent functioning [112]. Critically, patients with MCI are more likely to develop AD than cognitively normal adults [113-115], with higher conversion rates in amnestic MCI (aMCI) than nonamnestic MCI (naMCI) [113,116; also see 117 for a discussion of conversion rates]. Furthermore, MCI has been viewed as a possible prodromal stage of AD [112-114], so any changes in eye movements that are potentially detectable in MCI, especially aMCI, are greatly important to AD research.…”