title: The association of incident dementia with mortality in PD.
abstract: OBJECTIVE
  To evaluate the association of incident dementia with mortality in a cohort of patients with idiopathic PD who were nondemented at baseline evaluation, controlling for extrapyramidal sign (EPS) severity at each study visit.
  
  
  BACKGROUND
  The development of dementia has been associated with reduced survival in PD. Because EPS severity is associated with both dementia and mortality in PD, the association of dementia with mortality may be confounded by disease severity.
  
  
  METHODS
  A cohort of patients with PD was followed annually with neurologic and neuropsychological evaluations. The association of incident dementia and the total Unified PD Rating Scale (UPDRS) motor score with mortality in PD was examined using Cox proportional hazards models with time-dependent covariates. All analyses were adjusted for age at baseline, sex, years of education, ethnicity, and duration of PD.
  
  
  RESULTS
  Of 180 PD patients, 41 (22.8%) died during a mean follow-up period of 3.9 +/- 2.2 years. Among those who died during the study period, 48.8% (20 of 41) became demented during follow-up, as compared to 23.0% (32 of 139) of those who remained alive. Both incident dementia (RR: 2.2, 95% CI: 1.1 to 4.5, p = 0.04) and the total UPDRS motor score at each study visit (RR: 1.04, 95% CI: 1.02 to 1.07, p = 0.001) were associated with mortality in PD when included in the same Cox model.
  
  
  CONCLUSIONS
  Incident dementia has an independent effect on mortality when controlling for EPS severity. The development of dementia is associated with a twofold increased mortality risk in PD.
authors.affiliation: Gertrude H. Sergievsky Center, College of Physicians and Surgeons, New York, USA.
authors.forename: G
authors.initials: G
authors.lastname: Levy
authors.forename: M-X
authors.initials: MX
authors.lastname: Tang
authors.forename: E D
authors.initials: ED
authors.lastname: Louis
authors.forename: L J
authors.initials: LJ
authors.lastname: Côté
authors.forename: B
authors.initials: B
authors.lastname: Alfaro
authors.forename: H
authors.initials: H
authors.lastname: Mejia
authors.forename: Y
authors.initials: Y
authors.lastname: Stern
authors.forename: K
authors.initials: K
authors.lastname: Marder
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001480:Basal Ganglia Diseases / Q000503:physiopathology; D015331:Cohort Studies; D003704:Dementia / Q000150:complications / Q000401:mortality* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D009460:Neurologic Examination; D009483:Neuropsychological Tests; D009735:Nursing Homes; D010300:Parkinson Disease / Q000150:complications / Q000401:mortality* / Q000503:physiopathology; D011597:Psychomotor Performance / Q000502:physiology; D018570:Risk Assessment; D013997:Time Factors