title: How useful is the EQ-5D in assessing the impact of caring for people with Alzheimer's disease?
abstract: BACKGROUND
  The impact on informal caregivers of caring for people with Alzheimer's disease (AD) dementia can be substantial, but it remains unclear which measures(s) best assess such impact. Our objective was to use data from the GERAS study to assess the ability of the EuroQol 5-dimension questionnaire (EQ-5D) to measure the impact on caregivers of caring for people with AD dementia and to examine correlations between EQ-5D and caregiver burden.
  
  
  METHODS
  GERAS was a prospective, non-interventional cohort study in community-dwelling patients with AD dementia and their informal caregivers. The EQ-5D and Zarit Burden Interview (ZBI) were used to measure health-related quality of life and caregiver burden, respectively. Resource-use data collected included caregiver time spent with the patient on activities of daily living (ADL). Spearman correlations were computed between EQ-5D scores, ZBI scores, and time spent on instrumental ADL (T-IADL) at baseline, 18 months, and for 18-month change scores. T-IADL and ZBI change scores were summarized by EQ-5D domain change category (better/stable/worse).
  
  
  RESULTS
  At baseline, 1495 caregivers had mean EQ-5D index scores of 0.86, 0.85, and 0.82, and ZBI total scores of 24.6, 29.4, and 34.1 for patients with mild, moderate, and moderately severe/severe AD dementia, respectively. Change in T-IADL showed a stronger correlation with change in ZBI (0.12; P < 0.001) than with change in EQ-5D index score (0.02; P = 0.546) although both correlations were very weak. Worsening within EQ-5D domains was associated with increases in ZBI scores, although 68%-90% of caregivers remained stable within each EQ-5D domain. There was no clear pattern for change in T-IADL by change in EQ-5D domain.
  
  
  CONCLUSIONS
  EQ-5D may not be the optimum measure of the impact of caring for people with AD dementia due to its focus on physical health. Alternative measures need further investigation.
authors.affiliation: Eli Lilly and Company Limited, Erl Wood Manor, Sunninghill Road, Windlesham, Surrey, GU20 6PH, UK. reed_catherine@lilly.com.
authors.forename: Catherine
authors.initials: C
authors.lastname: Reed
authors.affiliation: Eli Lilly and Company Limited, Erl Wood Manor, Sunninghill Road, Windlesham, Surrey, GU20 6PH, UK.
authors.forename: Annabel
authors.initials: A
authors.lastname: Barrett
authors.affiliation: Lilly Deutschland GmbH, Bad Homburg, Germany.
authors.forename: Jeremie
authors.initials: J
authors.lastname: Lebrec
authors.affiliation: Philipps-University, Marburg, Germany.
authors.forename: Richard
authors.initials: R
authors.lastname: Dodel
authors.affiliation: RICE (The Research Institute for the Care of Older People), Royal United Hospital, Bath, UK.
authors.forename: Roy W
authors.initials: RW
authors.lastname: Jones
authors.affiliation: Toulouse University Hospital, Toulouse, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Vellas
authors.affiliation: Karolinska Institute, Stockholm, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Wimo
authors.affiliation: Servei Català de la Salut, Barcelona, Spain.
authors.forename: Josep Maria
authors.initials: JM
authors.lastname: Argimon
authors.affiliation: Sapienza University of Rome, Rome, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Bruno
authors.affiliation: Parc Sanitari Sant Joan de Déu, CIBERSAM, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Josep Maria
authors.initials: JM
authors.lastname: Haro
mesh_terms: D000203:Activities of Daily Living; D000223:Adaptation, Psychological; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000451:nursing*; D017028:Caregivers / Q000523:psychology*; D017281:Cost of Illness; D003430:Cross-Sectional Studies; D005260:Female; D005858:Germany; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011788:Quality of Life / Q000523:psychology*; D057566:Self Report; D011795:Surveys and Questionnaires / Q000592:standards*
keywords: Alzheimer’s disease; Caregiver burden; Europe; Health-related quality of life; Informal care; Observational study