title: Delirium is a risk factor for further cognitive decline in cognitively impaired hip fracture patients.
abstract: BACKGROUND
  Delirium is a risk factor for dementia in cognitively intact patients. Whether an episode of delirium accelerates cognitive decline in patients with known dementia, is less explored.
  
  
  METHODS
  This is a prospective follow-up study of 287 hip fracture patients with pre-fracture cognitive impairment. During the hospitalization, the patients were screened daily for delirium using the Confusion Assessment Method. Pre-fracture cognitive impairment was defined as a score of 3.44 or higher on the pre-fracture Informant Questionnaire on Cognitive Decline in the Elderly Short Form (IQCODE-SF). At follow-up after 4-6 months, the caregivers rated cognitive changes emerging after the fracture using the IQCODE-SF, and the patients were tested with the Mini Mental State Examination (MMSE). A sub-group of the patients had a pre-fracture MMSE score which was used to calculate the yearly decline on the MMSE in patients with and without delirium.
  
  
  RESULTS
  201 of the 287 patients developed delirium in the acute phase. In linear regression analysis, delirium was a significant and independent predictor of a more prominent cognitive decline at follow-up measured by the IQCODE-SF questionnaire (p=0.002). Among patients having a pre-fracture MMSE score, the patients developing delirium had a median (IQR) yearly decline of 2.4 points (1.1-3.9), compared to 1.0 points (0-1.9) in the group without delirium (p=0.001, Mann-Whitney test).
  
  
  CONCLUSIONS
  Hip fracture patients with pre-fracture dementia run a higher risk of developing delirium. Delirium superimposed on dementia is a significant predictor of an accelerated further cognitive decline.
authors.affiliation: Oslo Delirium Research Group, Department of Geriatric Medicine, Oslo University Hospital, Norway; Institute of Clinical Medicine, University of Oslo, Norway; Old Age Psychiatry Research Network, Telemark Hospital Trust and Vestfold Hospital Trust, 3710 Skien, Norway. Electronic address: mariakrogseth@gmail.com.
authors.forename: Maria
authors.initials: M
authors.lastname: Krogseth
authors.affiliation: Oslo Delirium Research Group, Department of Geriatric Medicine, Oslo University Hospital, Norway; Institute of Clinical Medicine, University of Oslo, Norway.
authors.forename: Leiv Otto
authors.initials: LO
authors.lastname: Watne
authors.affiliation: Oslo Delirium Research Group, Department of Geriatric Medicine, Oslo University Hospital, Norway; Department of Cardiology, Rikshospitalet, Oslo University Hospital, Norway.
authors.forename: Vibeke
authors.initials: V
authors.lastname: Juliebø
authors.affiliation: Department of Public Health and General Practice, NTNU, Trondheim, Norway; Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Eva
authors.initials: E
authors.lastname: Skovlund
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Norway; Norwegian Centre for Ageing and Health, Oslo University Hospital, Norway.
authors.forename: Knut
authors.initials: K
authors.lastname: Engedal
authors.affiliation: Department of Orthopaedic Surgery, Oslo University Hospital, Norway.
authors.forename: Frede
authors.initials: F
authors.lastname: Frihagen
authors.affiliation: Oslo Delirium Research Group, Department of Geriatric Medicine, Oslo University Hospital, Norway; Institute of Clinical Medicine, University of Oslo, Norway. Electronic address: t.b.wyller@medisin.uio.no.
authors.forename: Torgeir Bruun
authors.initials: TB
authors.lastname: Wyller
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003071:Cognition; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology; D003693:Delirium / Q000175:diagnosis*; D003704:Dementia / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D005500:Follow-Up Studies; D006620:Hip Fractures / Q000150:complications / Q000523:psychology*; D006760:Hospitalization; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires
keywords: Cognitive trajectories; Delirium; Dementia; Hip fracture