Progression of Alzheimer's Disease: A Longitudinal Study in Norwegian Memory Clinics

J Alzheimers Dis. 2018;61(3):1221-1232. doi: 10.3233/JAD-170436.


Background: The course of Alzheimer's disease (AD) varies considerably between individuals. There is limited evidence on factors important for disease progression.

Objective: The primary aim was to study the progression of AD, as measured by the Clinical Dementia Rating Scale Sum of Boxes (CDR-SB). Secondary aims were to investigate whether baseline characteristics are important for differences in progression, and to examine the correlation between progression assessed using three different instruments: CDR-SB (0-18), the cognitive test Mini-Mental State Examination (MMSE, 0-30), and the functional measure Instrumental Activities of Daily Living (IADL, 0-1).

Methods: The Progression of AD and Resource use (PADR) study is a longitudinal observational study in three Norwegian memory clinics.

Results: In total, 282 AD patients (mean age 73.3 years, 54% female) were followed for mean 24 (16-37) months. The mean annual increase in CDR-SB was 1.6 (SD 1.8), the mean decrease in MMSE score 1.9 (SD 2.6), and the mean decrease in IADL score 0.13 (SD 0.14). Of the 282 patients, 132 (46.8%) progressed slowly, with less than 1 point yearly increase in CDR-SB. Cognitive test results at baseline predicted progression rate, and together with age, ApoE, history of hypertension, and drug use could explain 17% of the variance in progression rate. The strongest correlation of change was found between CDR-SB and IADL scores, the weakest between MMSE and IADL scores.

Conclusion: Progression rate varied considerably among AD patients; about half of the patients progressed slowly. Cognitive test results at baseline were predictors of progression rate.

Keywords: Alzheimer’s disease; cognitive decline; dementia; mild cognitive impairment; prognosis; progression.

Publication types

  • Multicenter Study
  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activities of Daily Living
  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / physiopathology*
  • Alzheimer Disease / psychology*
  • Disease Progression*
  • Female
  • Humans
  • Linear Models
  • Longitudinal Studies
  • Male
  • Memory
  • Neuropsychological Tests
  • Norway