title: Mortality associated with delirium after hip-surgery: a 2-year follow-up study.
abstract: BACKGROUND
  delirium after hip-surgery is associated with poor outcome. Few studies examined the mortality risk associated with delirium in elderly hip-surgery patients after 1 year or more. Aim of this study was to examine the hazard risk associated with delirium in elderly hip-surgery patients at 2-year follow-up, controlling for baseline risk factors and interaction effects.
  
  
  METHODS
  this is a secondary analysis based on data from a controlled clinical trial evaluating efficacy of haloperidol prophylaxis for delirium conducted in a large medical school-affiliated general hospital in Alkmaar, The Netherlands. Randomised and non-randomised patients (n = 603) were followed-up for 2 years. Predefined risk factors and other potential risk factors for delirium were assessed prior to surgery. Primary outcome was time of death during the follow-up period. Cox proportional hazards were estimated and compared across patients who had postoperative delirium during hospitalisation and those who did not.
  
  
  RESULTS
  a total of 90/603 patients (14.9%) died during the study period and 74/603 (12.3%) had postoperative delirium. Incidence of delirium was higher in patients who died (32.2%) compared with those who survived (8.8%). The interaction effect of delirium by illness severity on mortality was significant after adjusting for predefined delirium risk factors and other potential covariates including study intervention (adjusted Hazard risk = 1.05, 95% CI 1.02-1.08). A total of 14/27 delirium patients who were severely ill on admission died during follow-up versus 15/47 delirium patients who were not (RR 1.63 CI 0.93-2.83).
  
  
  CONCLUSIONS
  delirium does not independently predict mortality at 2-year follow-up in elderly hip-surgery patients. However, outcome from delirium is particularly poor when other risk factors are present.
authors.affiliation: Department of Geriatric Medicine, Medical Center Alkmaar, Alkmaar, The Netherlands. psykat@hetnet.nl
authors.forename: Martin G
authors.initials: MG
authors.lastname: Kat
authors.forename: Jos F
authors.initials: JF
authors.lastname: de Jonghe
authors.forename: Ralph
authors.initials: R
authors.lastname: Vreeswijk
authors.forename: Tjeerd
authors.initials: T
authors.lastname: van der Ploeg
authors.forename: Willem A
authors.initials: WA
authors.lastname: van Gool
authors.forename: Piet
authors.initials: P
authors.lastname: Eikelenboom
authors.forename: Kees J
authors.initials: KJ
authors.lastname: Kalisvaart
mesh_terms: D000368:Aged; D014150:Antipsychotic Agents / Q000627:therapeutic use; D003693:Delirium / Q000150:complications* / Q000188:drug therapy / Q000401:mortality* / Q000523:psychology; D005260:Female; D005500:Follow-Up Studies; D006220:Haloperidol / Q000627:therapeutic use; D006615:Hip / Q000601:surgery*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D011183:Postoperative Complications / Q000401:mortality* / Q000523:psychology; D011184:Postoperative Period; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D014150:Antipsychotic Agents; D006220:Haloperidol