title: Quality of life in patients with cognitive impairment: validation of the Quality of Life-Alzheimer's Disease scale in Portugal.
abstract: BACKGROUND
  Quality of Life-Alzheimer's Disease (QOL-AD) is a widely used scale for the study of quality of life in patients with dementia. The aim of this study is the transcultural adaptation and validation of the QOL-AD scale in Portugal.
  
  
  METHODS
  Translation and transcultural adaptation was performed according to state-of-the-art recommendations. For the validation study, 104 patient/caregiver pairs were enrolled. Patients had mild cognitive impairment or mild-to-moderate dementia (due to Alzheimer's disease or vascular dementia). Participants were recruited in a dementia outpatient clinic setting and a long-term care dementia ward. An additional comparison group of 22 patients without cognitive impairment, and their proxies, was recruited in a family practice outpatient clinic. Sociodemographic information on patients and caregivers was obtained. Acceptability, reliability, and construct validity were analyzed.
  
  
  RESULTS
  Internal consistency of the Portuguese version of QOL-AD was good for both patient and caregiver report (Cronbach's α = 0.867 and 0.858, respectively). Construct validity was confirmed by the correlation of patient reported QOL-AD with patient geriatric depression scale scores (ρ = -0.702, p < 0.001) and satisfaction with life scale scores (ρ = 0.543, p < 0.001). Caregiver ratings were correlated with neuropsychiatric inventory (NPI) total score (ρ = -0.404, p < 0.001), NPI-distress (ρ = -0.346, p < 0.001), and patient Mini-Mental State Examination (ρ = 0.319, p < 0.01). QOL-AD patient ratings were higher than caregiver ratings (p < 0.001). Both patient- and caregiver-rated QOL-AD scores were lower in patients with cognitive impairment than in the comparison group without cognitive impairment (p < 0.01).
  
  
  CONCLUSIONS
  A Portuguese version of QOL-AD with consistent psychometric properties was obtained and is proposed as a useful tool for research and clinical purposes.
authors.affiliation: Dementia Group, Institute of Molecular Medicine and Faculty of Medicine, University of Lisbon, Lisbon, Portugal. hsbarrios@hrmar.pt
authors.forename: Helena
authors.initials: H
authors.lastname: Bárrios
authors.forename: Ana
authors.initials: A
authors.lastname: Verdelho
authors.forename: Sofia
authors.initials: S
authors.lastname: Narciso
authors.forename: Manuel
authors.initials: M
authors.lastname: Gonçalves-Pereira
authors.forename: Rebecca
authors.initials: R
authors.lastname: Logsdon
authors.forename: Alexandre
authors.initials: A
authors.lastname: de Mendonça
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017028:Caregivers / Q000523:psychology; D003072:Cognition Disorders / Q000175:diagnosis / Q000523:psychology*; D003704:Dementia / Q000175:diagnosis / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D011174:Portugal; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results