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

• Published in: Aging & mental health Vol. 15; no. 6; pp. 775 - 783
• Main Authors: León-Salas, B., Logsdon, R.G., Olazarán, J., Martínez-Martín, P., The MSU-ADRU
• Format: Journal Article
• Language: English
• Published: England Routledge 01.08.2011
• Subjects: Adult; Aged; Aged, 80 and over; Alzheimer Disease - diagnosis; Alzheimer Disease - psychology; Alzheimer's disease; Caregivers - psychology; Carers; Dementia - diagnosis; Dementia - psychology; Female; Humans; Institutionalization; Institutionalized; Male; Middle Aged; Minimental State Examination; patient-caregiver reports; Patients; Psychiatry; Psychological Tests - standards; psychometric properties; Psychometrics; Psychosociology; Quality of life; Quality of Life - psychology; Social welfare; Spain; validation; Young Adult; Spain
• ISSN: 1360-7863; 1364-6915
• DOI: 10.1080/13607863.2011.562183

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.