title: Surrogate inaccuracy in predicting older adults' desire for life-sustaining interventions in the event of decisional incapacity: is it due in part to erroneous quality-of-life assessments?
abstract: Family members are often called upon to make decisions for an incapacitated relative. Yet they have difficulty predicting a loved one's desire to receive treatments in hypothetical situations. We tested the hypothesis that this difficulty could in part be explained by discrepant quality-of-life assessments.
  
  
  
  The data come from 235 community-dwelling adults aged 70 years and over who rated their quality of life and desire for specified interventions in four health states (current state, mild to moderate stroke, incurable brain cancer, and severe dementia). All ratings were made on Likert-type scales. Using identical rating scales, a surrogate chosen by the older adult was asked to predict the latter's responses. Linear mixed models were fitted to determine whether differences in quality-of-life ratings between the older adult and surrogate were associated with surrogates' inaccuracy in predicting desire for treatment.
  
  
  
  The difference in quality-of-life ratings was a significant predictor of prediction inaccuracy for the three hypothetical health states (p < 0.01) and nearly significant for the current health state (p = 0.077). All regression coefficients were negative, implying that the more the surrogate overestimated quality of life compared to the older adult, the more he or she overestimated the older adult's desire to be treated.
  
  
  
  Discrepant quality-of-life ratings are associated with surrogates' difficulty in predicting desire for life-sustaining interventions in hypothetical situations. This finding underscores the importance of discussing anticipated quality of life in states of cognitive decline, to better prepare family members for making difficult decisions for their loved ones.
  
  
  
  ISRCTN89993391.
authors.affiliation: Department of Community Health Sciences,Faculty of Medicine and Health Sciences,Université de Sherbrooke,Sherbrooke,Quebec,Canada.
authors.forename: Gina
authors.initials: G
authors.lastname: Bravo
authors.affiliation: Research Centre on Aging,University Institute of Geriatrics of Sherbrooke,Sherbrooke,Quebec,Canada.
authors.forename: Modou
authors.initials: M
authors.lastname: Sene
authors.affiliation: Research Centre on Aging,University Institute of Geriatrics of Sherbrooke,Sherbrooke,Quebec,Canada.
authors.forename: Marcel
authors.initials: M
authors.lastname: Arcand
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000523:psychology; D060825:Cognitive Dysfunction / Q000523:psychology*; D003657:Decision Making; D003704:Dementia / Q000523:psychology; D005260:Female; D005544:Forecasting; D006801:Humans; D057187:Independent Living; D008020:Life Support Care; D016014:Linear Models; D008297:Male; D019727:Proxy; D011788:Quality of Life / Q000523:psychology*; D020521:Stroke / Q000523:psychology
keywords: agreement; cognitive impairment; concordance; elderly; healthcare; proxy; quality of life; substitute decision making