A hierarchy of predictors for dementia-free survival in old-age: results of the AgeCoDe study

Acta Psychiatr Scand. 2014 Jan;129(1):63-72. doi: 10.1111/acps.12129. Epub 2013 Mar 22.

Abstract

Objective: Progression from cognitive impairment (CI) to dementia is predicted by several factors, but their relative importance and interaction are unclear.

Method: We investigated numerous such factors in the AgeCoDe study, a longitudinal study of general practice patients aged 75+. We used recursive partitioning analysis (RPA) to identify hierarchical patterns of baseline covariates that predicted dementia-free survival.

Results: Among 784 non-demented patients with CI, 157 (20.0%) developed dementia over a follow-up interval of 4.5 years. RPA showed that more severe cognitive compromise, revealed by a Mini-Mental State Examination (MMSE) score < 27.47, was the strongest predictor of imminent dementia. Dementia-free survival time was shortest (mean 2.4 years) in such low-scoring patients who also had impaired instrumental activities of daily living (iADL) and subjective memory impairment with related worry (SMI-w). Patients with identical characteristics but without SMI-w had an estimated mean dementia-free survival time of 3.8 years, which was still shorter than in patients who had subthreshold MMSE scores but intact iADL (4.2-5.2 years).

Conclusion: Hierarchical patterns of readily available covariates can predict dementia-free survival in older general practice patients with CI. Although less widely appreciated than other variables, iADL impairment appears to be an especially noteworthy predictor of progression to dementia.

Keywords: cognitive impairment; dementia; diagnosis; epidemiology; old-age.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activities of Daily Living*
  • Age Factors
  • Aged
  • Aged, 80 and over
  • Cognitive Dysfunction / psychology*
  • Dementia / psychology*
  • Disease Progression
  • Female
  • Humans
  • Longitudinal Studies
  • Male
  • Memory Disorders / psychology
  • Mental Status Schedule
  • Prodromal Symptoms*
  • Risk Factors
  • Severity of Illness Index