title: The diagnosis, prevalence and outcome of delirium in a cohort of older people with mental health problems on general hospital wards.
abstract: OBJECTIVE
  This paper aimed to measure the prevalence and outcomes of delirium for patients over 70 admitted to a general hospital for acute medical care and to assess the validity of the Delirium Rating Scale-Revised-98 (DRS-R-98) in this setting.
  
  
  METHODS
  Prospective study in a British acute general hospital providing sole emergency medical services for its locality. We screened consecutive patients over 70 with an unplanned emergency hospital admission and recruited a cohort of 249 patients likely to have mental health problems. They were assessed for health status at baseline and followed over 6 months. A sub-sample of 93 participants was assessed clinically for delirium.
  
  
  RESULTS
  27% (95% confidence interval (CI) 23-31) of all older medical patients admitted to hospital had DRS-diagnosed delirium, and 41% (95% CI 37-45) had dementia (including 19% with co-morbid delirium and dementia). Compared with clinician diagnosis, DRS-R-98 sensitivity was at least 0.75, specificity 0.71. Compared with reversible cognitive impairment, sensitivity was at least 0.50, specificity 0.67. DRS-diagnosed delirium was associated with cognitive impairment, mood, behavioural and psychological symptoms, activities of daily living, and number of drugs prescribed, supporting construct validity. Of those with DRS-diagnosed delirium, 37% died within 6 months (relative risk 1.4, 95% CI 0.97-2.2), 43% had reversible cognitive impairment, but only 25% had clinically important recovery in activities of daily living. Behavioural and psychological symptoms were common and mostly resolved, but new symptoms frequently developed.
  
  
  CONCLUSIONS
  Delirium is common. Some, but not all, features are reversible. DRS-R-98 has reasonable validity in populations where co-morbid dementia is prevalent.
authors.affiliation: Health Care of Older People, Nottingham University Hospitals NHS Trust, Queens Medical Centre, Nottingham, UK.
authors.forename: Kathy H
authors.initials: KH
authors.lastname: Whittamore
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Goldberg
authors.forename: John R F
authors.initials: JR
authors.lastname: Gladman
authors.forename: Lucy E
authors.initials: LE
authors.lastname: Bradshaw
authors.forename: Rob G
authors.initials: RG
authors.lastname: Jones
authors.forename: Rowan H
authors.initials: RH
authors.lastname: Harwood
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003693:Delirium / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality; D005260:Female; D006769:Hospitals, General / Q000706:statistics & numerical data; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D001523:Mental Disorders / Q000150:complications*; D017063:Outcome Assessment, Health Care; D010359:Patient Readmission / Q000706:statistics & numerical data; D015995:Prevalence; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales / Q000592:standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D006113:United Kingdom / Q000453:epidemiology
keywords: Delirium Rating Scale; delirium; diagnosis; general hospital; older person; prognosis; validity