Psychometric properties of the Spanish QoL-AD with institutionalized dementia patients and their family caregivers in Spain

Aging Ment Health. 2011 Aug;15(6):775-83. doi: 10.1080/13607863.2011.562183. Epub 2011 May 24.


Objectives: To evaluate the psychometric attributes of the Spanish version of the Quality of Life-Alzheimer's Disease Scale (QoL-AD) in institutionalized patients and family caregivers in Spain.

Method: 101 patients (88.1% women; mean age, 83.2 ± 6.3) with Alzheimer's disease (AD) (n = 82) and mixed dementia (n = 19) and their closest family caregivers. Patient-related variables included severity of dementia, cognitive status, perceived general health, quality of life, behavior, apathy, depression, and functional status. QoL-AD acceptability, reliability, and construct validity were analyzed.

Results: The mean Mini-Mental State Examination (MMSE) score was 7.2 ± 6.1 and Global Deterioration Scale was: stage four (4%); five (21.2%); six (34.3%); and seven (40.4%). Both, QoL-AD patient version (QoL-ADp) (n = 40; MMSE = 12.0 ± 4.5) and QoL-AD caregiver version (QoL-ADc) (n = 101) lacked significant floor and ceiling effects and the Cronbach α index was 0.90 and 0.86, respectively. The corrected item-total correlation was 0.11-0.68 (QoL-ADc) and 0.28-0.84 (QoL-ADp). Stability was satisfactory for QoL-ADp (intraclass correlation coefficient [ICC]=0.83) but low for QoL-ADc (ICC = 0.51); the standard error of measurement was 2.72 and 4.69. Construct validity was moderate/high for QoL-ADc (QUALID=-0.43; EQ-5D = 0.65), but lower for QoL-ADp. No significant correlations were observed between QoL-ADp and patient variables or QoL-ADc. A low to high association (r = 0.18-0.55) was obtained between QoL-ADc and patient-related measures of neuropsychiatric, function, and cognitive status.

Conclusion: Differences in their psychometric attributes, and discrepancy between them, were found for QoL-ADp and QoL-ADc. In patients with AD and advanced dementia, the QoL perceived by the patient could be based on a construct that is different from the traditional QoL construct.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / diagnosis
  • Alzheimer Disease / psychology
  • Caregivers / psychology*
  • Dementia / diagnosis
  • Dementia / psychology*
  • Female
  • Humans
  • Institutionalization
  • Male
  • Middle Aged
  • Psychological Tests / standards
  • Psychometrics
  • Quality of Life / psychology*
  • Spain
  • Young Adult