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BioMed Research International
Volume 2014 (2014), Article ID 623487, 7 pages
Research Article

Factors Determining Disease Duration in Alzheimer’s Disease: A Postmortem Study of 103 Cases Using the Kaplan-Meier Estimator and Cox Regression

Vision Sciences, Aston University, Birmingham B4 7ET, UK

Received 26 April 2013; Revised 5 November 2013; Accepted 24 November 2013; Published 22 January 2014

Academic Editor: Maurizio Gallucci

Copyright © 2014 R. A. Armstrong. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Factors associated with duration of dementia in a consecutive series of 103 Alzheimer’s disease (AD) cases were studied using the Kaplan-Meier estimator and Cox regression analysis (proportional hazard model). Mean disease duration was 7.1 years (range: 6 weeks–30 years, standard deviation = 5.18); 25% of cases died within four years, 50% within 6.9 years, and 75% within 10 years. Familial AD cases (FAD) had a longer duration than sporadic cases (SAD), especially cases linked to presenilin (PSEN) genes. No significant differences in duration were associated with age, sex, or apolipoprotein E (Apo E) genotype. Duration was reduced in cases with arterial hypertension. Cox regression analysis suggested longer duration was associated with an earlier disease onset and increased senile plaque (SP) and neurofibrillary tangle (NFT) pathology in the orbital gyrus (OrG), CA1 sector of the hippocampus, and nucleus basalis of Meynert (NBM). The data suggest shorter disease duration in SAD and in cases with hypertensive comorbidity. In addition, degree of neuropathology did not influence survival, but spread of SP/NFT pathology into the frontal lobe, hippocampus, and basal forebrain was associated with longer disease duration.