title: Assessing agreement between terminally ill cancer patients' reports of their quality of life and family caregiver and palliative care physician proxy ratings.
abstract: BACKGROUND
  Proxy ratings, if valid, may provide an alternative approach to evaluating patient quality of life (QoL) at the end of life.
  
  
  OBJECTIVE
  To examine agreement between terminally ill cancer patients' self-reported QoL and proxy assessment of patient QoL by their family caregiver (FCG) and palliative care physicians (PCPs) at two time points.
  
  
  METHODS
  Patients admitted to an acute palliative care unit and their FCGs and PCPs completed the McGill Quality of Life Questionnaire (MQOL) at Days 3 and 6 after admission. Response bias and response precision were examined at the individual and group levels. Furthermore, we examined patient factors affecting agreement and responsiveness of proxy MQOL scores to changes in patients' QoL between Days 3 and 6.
  
  
  RESULTS
  Statistically and clinically significant mean differences were detected between the patient and both proxy groups' reports of QoL on Day 3, with the magnitude of the differences decreasing somewhat by Day 6. Proxies underestimated patients' QoL compared with patients' self-report. Response precision based on intraclass correlation values and proportion of approximate agreement was poor to fair at both time points. Agreement was better for patients with greater physical burden and more cognitive difficulties. Proxies' responsiveness to change from Day 3 to Day 6 was low, and proxies were not able to detect minimally important changes in QoL.
  
  
  CONCLUSIONS
  The findings suggest that moderate agreement between patient and proxy ratings of QoL develops over time but that precision at the individual level, which is more clinically relevant, is less reliable. New strategies for improving proxy reliability are needed.
authors: Department of Psychosocial Oncology and Palliative Care, Princess Margaret Hospital, Toronto, Ontario, Canada. jennifer.jones@uhn.on.ca
authors: Jennifer M
authors: JM
authors: Jones
authors: Christine J
authors: CJ
authors: McPherson
authors: Camilla
authors: C
authors: Zimmermann
authors: Gary
authors: G
authors: Rodin
authors: Lisa W
authors: LW
authors: Le
authors: S Robin
authors: SR
authors: Cohen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017028:Caregivers / Q000523:psychology*; D005190:Family / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000523:psychology; D010166:Palliative Care; D010820:Physicians; D011446:Prospective Studies; D019727:Proxy / Q000523:psychology; D011788:Quality of Life / Q000523:psychology*; D057566:Self Report; D013727:Terminal Care / Q000523:psychology; D019452:Terminally Ill / Q000523:psychology*