title: Preexisting cognitive impairment is associated with postoperative cognitive dysfunction after hip joint replacement surgery.
abstract: BACKGROUND
  This study investigated the prevalence of cognitive impairment in elderly noncardiac surgery patients and any association between preoperative cognitive impairment and postoperative cognitive dysfunction (POCD). Additionally, the incidence of cognitive decline at 12 months after surgery was identified.
  
  
  METHODS
  Three hundred patients for hip joint replacement and 51 nonsurgical controls aged 60 yr or older were studied in a prospective observational clinical trial. All study participants and controls completed a battery of eight neuropsychological tests before surgery and at 7 days, 3 months, and 12 months afterwards. Preoperative cognitive status was assessed using preexisting cognitive impairment (PreCI) defined as a decline of at least 2 SD on two or more of seven neuropsychological tests compared to population norms. POCD and cognitive decline were assessed using the reliable change index utilizing the results of the control group.
  
  
  RESULTS
  PreCI was classified in 96 of 300 (32%) patients (95% CI, 23 to 43%). After surgery, 49 of 286 (17%) patients (95% CI, 13 to 22%) and 27 of 284 (10%) patients (95% CI, 6 to 13%) demonstrated POCD at 7 days and 3 months, respectively, while 7 of 271 (3%) patients (95% CI, 1 to 4%) demonstrated cognitive decline at 12 months. Patients with PreCI had a significantly increased incidence of POCD at 7 days and 3 months and cognitive decline at 12 months.
  
  
  CONCLUSIONS
  Patients with PreCI have an increased incidence of POCD and cognitive decline. PreCI is a good predictor of subsequent POCD and cognitive decline. The incidence of cognitive decline after 12 months in this group of patients is low.
authors: From the Centre for Anaesthesia and Cognitive Function, Department of Anaesthesia, St. Vincent's Hospital, Melbourne, Victoria, Australia (B.S., L.E., D.A.S.); Anaesthesia, Perioperative and Pain Medicine Unit, Melbourne Medical School, University of Melbourne, Melbourne, Victoria, Australia (B.S., L.E., D.A.S.,); Department of Surgery, Monash University, Melbourne, Victoria, Australia (S.M.); Malabar Orthopaedic Clinic, Windsor, Victoria, Australia (S.M.); Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia (P.C.); Department of Orthopaedics, St. Vincent's Hospital, Melbourne, Victoria, Australia (P.C.); Academic Unit for Psychiatry of Old Age, Department of Psychiatry, University of Melbourne, Parkville, Victoria, Australia (D.A.); National Aging Research Institute, Parkville, Victoria, Australia (D.A.); Florey Institute for Neuroscience and Mental Health, Parkville, Victoria, Australia (P.M.); and School of Population Health, University of Adelaide, Adelaide, South Australia, Australia (K.J.).
authors: Brendan
authors: B
authors: Silbert
authors: Lisbeth
authors: L
authors: Evered
authors: David A
authors: DA
authors: Scott
authors: Stephen
authors: S
authors: McMahon
authors: Peter
authors: P
authors: Choong
authors: David
authors: D
authors: Ames
authors: Paul
authors: P
authors: Maruff
authors: Konrad
authors: K
authors: Jamrozik
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000523:psychology*; D003072:Cognition Disorders / Q000209:etiology / Q000523:psychology*; D056805:Consciousness Monitors; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011183:Postoperative Complications / Q000523:psychology*; D064266:Preexisting Condition Coverage; D011446:Prospective Studies