title: Risk Factors for Progression of Alzheimer Disease in a Canadian Population: The Canadian Outcomes Study in Dementia (COSID).
abstract: OBJECTIVE
  To determine risk factors for clinically significant progression during 12 months in patients with mild-to-moderate Alzheimer disease.
  
  
  METHODS
  Community-dwelling patients with mild-to-moderate Alzheimer disease were enrolled in a 3-year prospective study, the Canadian Outcomes Study in Dementia (commonly referred to as COSID), at 32 Canadian sites. Assessments included the Global Deterioration Scale (GDS) for disease severity, the Mini-Mental State Examination (MMSE) for cognition, the Functional Autonomy Measurement System (SMAF) for daily functioning, and the NeuroPsychiatric Inventory (NPI) for behaviour, measured at baseline and at 12 months. Logistic regression identified factors associated with GDS decline, and subsequent stepwise regression identified key independent predictors. Area under the curve (AUC) was then calculated for the model.
  
  
  RESULTS
  Among 488 patients (mean age 76.5 years [SD 6.4], MMSE 22.1 [SD4.6], 44.1% male), 225 (46%) showed GDS decline. After adjusting for age, baseline risk factors for deterioration included the following: poorer cognition (lower MMSE score, OR 0.55; 95% CI 0.4 to 0.72 per 5 points, P ≤ 0.001), greater dependence (lower SMAF, OR 0.72; 95% CI 0.63 to 0.83 per 5 points, P ≤ 0.001), and more neuropsychiatric symptoms (higher NPI, OR 1.11; 95% CI 1.02 to 1.2 per 5 points, P = 0.02), with a protective effect of male sex (OR 0.59; 95% CI 0.39 to 0.9, P = 0.02), and higher (worse) GDS score (very mild, compared with mild OR 0.25; 95% CI 0.09 to 0.70, P ≤ 0.01; compared with moderate, OR 0.08; 95% CI 0.03 to 0.23, P < 0.001; compared with moderately severe, OR 0.03; 95% CI 0.01 to 0.11, P < 0.001). The AUC was 73% (P < 0.001) (sensitivity 90% and specificity 33%).
  
  
  CONCLUSIONS
  The progression of Alzheimer disease in Canada can be predicted using readily available clinical information.
authors.affiliation: Head, Division of Geriatric Psychiatry, Sunnybrook Health Sciences Centre, Toronto, Ontario; Professor, Faculty of Medicine, Department of Psychiatry, University of Toronto, Toronto, Ontario.
authors.forename: Nathan
authors.initials: N
authors.lastname: Herrmann
authors.affiliation: Research Assistant, Medical Outcome and Research in Economics Group (MORE), Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario.
authors.forename: Tetsuhiro
authors.initials: T
authors.lastname: Harimoto
authors.affiliation: Senior Scientist, Statistician, BC Centre for Disease Control, Vancouver, British Columbia.
authors.forename: Robert
authors.initials: R
authors.lastname: Balshaw
authors.affiliation: Executive Director, Medical Outcome and Research in Economics Group (MORE), Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario; Professor, Department of Psychiatry and Pharmacology and Toxicology, University of Toronto, Toronto, Ontario.
authors.forename: Krista L
authors.initials: KL
authors.lastname: Lanctôt
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000453:epidemiology*; D002170:Canada / Q000453:epidemiology; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index