title: Psychometric properties of the Spanish QoL-AD with institutionalized dementia patients and their family caregivers in Spain.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Alzheimer Disease Research Unit, CIEN Foundation, Carlos III Institute of Health, Alzheimer Center Reina Sofia Foundation, Madrid, Spain. bleon@fundacioncien.es
authors.forename: B
authors.initials: B
authors.lastname: León-Salas
authors.forename: R G
authors.initials: RG
authors.lastname: Logsdon
authors.forename: J
authors.initials: J
authors.lastname: Olazarán
authors.forename: P
authors.initials: P
authors.lastname: Martínez-Martín
authors.lastname: The Msu-Adru
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000523:psychology; D017028:Caregivers / Q000523:psychology*; D003704:Dementia / Q000175:diagnosis / Q000523:psychology*; D005260:Female; D006801:Humans; D007326:Institutionalization; D008297:Male; D008875:Middle Aged; D011581:Psychological Tests / Q000592:standards; D011594:Psychometrics; D011788:Quality of Life / Q000523:psychology*; D013030:Spain; D055815:Young Adult