title: History of a suspected delirium is more common in dementia with Lewy bodies than Alzheimer's disease: a retrospective study.
abstract: BACKGROUND
  Delirium is common and is associated with an increased risk of dementia. However, it is not clear whether delirium confers increased risk of any particular type of dementia. We performed a retrospective study of Alzheimer's disease (AD) and Dementia with Lewy bodies (DLB) to ascertain whether a suspected episode of preceding delirium was more common prior to diagnosis in either type of dementia.
  
  
  METHODS
  The study was carried out in a tertiary referral unit for the diagnosis of dementia. Clinic letters from the first presentation to the unit of 85 cases with DLB and 95 cases of AD were reviewed for documentation of any previous episodes of suspected delirium.
  
  
  RESULTS
  In this study, 25% of DLB cases had at least one reported episode of suspected delirium as compared to 7% of AD cases (p = 0.001). For the DLB cases who had a prior suspected delirium, 23% had more than one episode compared with 14% of the AD group. The median time between most recent suspected episode of delirium and diagnosis of dementia in both groups was less than a year
  
  
  CONCLUSIONS
  A greater proportion of those presenting and diagnosed with DLB had a documentation of a suspected delirium than those diagnosed with AD. Delirium may lead to a higher risk of DLB as opposed to other forms of dementia, or delirium may, at least in some cases, represent the early stages of DLB. These data suggest that a diagnosis of DLB should be specifically considered in those presenting with a delirium.
authors.affiliation: Department of Older Peoples Medicine, Newcastle upon Tyne hospitals NHS Foundation Trust, Freeman Hospital, Newcastle upon Tyne, NE7 7DN, UK; Institute of Ageing and Health, Campus of Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE4 5PL, UK.
authors.forename: Emma
authors.initials: E
authors.lastname: Vardy
authors.forename: Rachel
authors.initials: R
authors.lastname: Holt
authors.forename: Alex
authors.initials: A
authors.lastname: Gerhard
authors.forename: Anna
authors.initials: A
authors.lastname: Richardson
authors.forename: Julie
authors.initials: J
authors.lastname: Snowden
authors.forename: David
authors.initials: D
authors.lastname: Neary
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000523:psychology*; D003693:Delirium / Q000453:epidemiology*; D005260:Female; D006801:Humans; D020961:Lewy Body Disease / Q000523:psychology*; D008297:Male; D015995:Prevalence; D012189:Retrospective Studies; D012306:Risk
keywords: Alzheimer's disease; Dementia with Lewy bodies; delirium; dementia