title: The estimated life expectancy in a community cohort of Parkinson's disease patients with and without dementia, compared with the UK population.
abstract: OBJECTIVE
  To compare survival, life expectancies (LE), and the anticipated age at the time of death (AAD), in a community-based cohort of Parkinson's disease (PD) patients with and without significant cognitive impairment, with an age sex matched population of England and Wales.
  
  
  METHODS
  The age- and sex-specific standardised mortality ratios (SMR) were calculated and stratified by dementia status. The LE and AAD estimations were calculated from the SMRs of the 2003 UK population, using a modified Gompertz function.
  
  
  RESULTS
  In total, 166 PD patients participated in the investigation, of which 91 died by the 4-year follow-up. The overall SMR was 2.09 (95% CI 1.68 to 2.57). Demented patients had significantly higher SMRs than non-demented patients (SMR 3.10, 95% CI 2.39 to 3.96 vs SMR 1.15, 95% CI 0.75 to 1.69, p<0.001). In our cohort, the LE in younger-onset demented patients (55-74 years) was much lower than in non-demented patients (7.5; SD 3 vs 12.4; SD 7). Likewise, the estimated AAD in younger onset patients with dementia was also much lower (demented 72.4; SD 4 vs not demented 77.8; SD 7). In older-onset patients with dementia (>75 years), the differences in LE (demented 2.1; SD 1 vs not demented 4.7; SD 4) and AAD were less apparent (demented 89.5; SD 6 vs not demented 92.2; SD 6).
  
  
  CONCLUSIONS
  The survival, LE and AAD in patients with PD are much lower compared with the general population, apart from those patients who do not develop dementia, who appear to have near normal population mortalities. However, dementia and younger onset of PD appear to be important determinants of survival, LE and AAD.
authors.affiliation: Academic Unit (North Wales), Cardiff University, Glan Clwyd Hospital, Rhyl, UK. peterhobson@hotmail.com
authors.forename: Peter
authors.initials: P
authors.lastname: Hobson
authors.forename: Jolyon
authors.initials: J
authors.lastname: Meara
authors.forename: Lianna
authors.initials: L
authors.lastname: Ishihara-Paul
mesh_terms: D017668:Age of Onset; D000368:Aged; D015331:Cohort Studies; D003704:Dementia / Q000150:complications / Q000453:epidemiology / Q000401:mortality*; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D008017:Life Expectancy; D008297:Male; D010300:Parkinson Disease / Q000150:complications / Q000453:epidemiology / Q000401:mortality*; D016019:Survival Analysis; D014852:Wales / Q000453:epidemiology