title: An evaluation of the additional benefit of population screening for dementia beyond a passive case-finding approach.
abstract: OBJECTIVE
  General practitioners (GPs) fail to identify more than 50% of dementia cases using the existing passive case-finding approach. Using data from the "Ageing in General Practice" study, we sought to establish the additional benefit of screening all patients over the age of 75 for dementia beyond those patients already identified by passive case-finding.
  
  
  METHODS
  Patients were classified as "case-finding" (n = 425) or "screening" (n = 1006) based on their answers to four subjective memory related questions or their GP's clinical judgement of their dementia status. Cognitive status of each patient was formally assessed by a research nurse using the Cambridge Cognition Examination (CAMCOG-R). Patients then attended their usual GP for administration of the GP assessment of Cognition (GPCOG) dementia screening instrument, and follow-up care and/or referral as necessary in light of the outcome.
  
  
  RESULTS
  The prevalence of dementia was significantly higher in the case-finding group (13.6%) compared to the screening group (4.6%; p < 0.01). The GPCOG had a positive predictive value (PPV) of 61% in the case-finding group and 39% in the screening group; negative predictive value was >95% in both groups. GPs and their patients both found the GPCOG to be an acceptable cognitive assessment tool. The dementia cases missed via case-finding were younger (p = 0.024) and less cognitively impaired (p = 0.020) than those detected.
  
  
  CONCLUSIONS
  There is a very limited benefit of screening for dementia, as most people with dementia could be detected using a case-finding approach, and considerable potential for social and economic harm because of the low PPV associated with screening.
authors.affiliation: School of Biomedical Sciences and Pharmacy, University of Newcastle, NSW, Australia.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Mate
authors.affiliation: School of Medicine and Public Health, University of Newcastle, NSW, Australia.
authors.forename: Parker J
authors.initials: PJ
authors.lastname: Magin
authors.affiliation: Dementia Collaborative Research Centre and Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, NSW, Australia.
authors.forename: Henry
authors.initials: H
authors.lastname: Brodaty
authors.affiliation: Discipline of General Practice, School of Population Health, The University of Adelaide, SA, Australia.
authors.forename: Nigel P
authors.initials: NP
authors.lastname: Stocks
authors.affiliation: Department of General Practice The University of Melbourne, VIC, Australia.
authors.forename: Jane
authors.initials: J
authors.lastname: Gunn
authors.affiliation: School of Rural Health, Monash University, Bendigo, VIC, Australia.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Disler
authors.affiliation: School of Biomedical Sciences and Pharmacy, University of Newcastle, NSW, Australia.
authors.forename: John E
authors.initials: JE
authors.lastname: Marley
authors.affiliation: School of Medicine and Public Health, University of Newcastle, NSW, Australia.
authors.forename: C Dimity
authors.initials: CD
authors.lastname: Pond
mesh_terms: D000368:Aged; D003071:Cognition; D003704:Dementia / Q000175:diagnosis / Q000523:psychology; D005194:Family Practice; D005260:Female; D058006:General Practice; D006801:Humans; D008297:Male; D008403:Mass Screening; D000073216:Mental Status and Dementia Tests; D008875:Middle Aged; D015995:Prevalence
keywords: case-finding; dementia; primary care; screening