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.

Background: Alzheimer's disease (AD) is a chronic medical condition with symptoms that compromise patients’ quality of life (QoL). The identification of the factor predicting QoL in AD is essential to develop more effective interventions. Recent research suggests that these factors could be different for the distinct informants. This study explores the QoL predictors considering three different sources of information: patients, caregivers, and healthcare staff.

Methods: In this cross-sectional study, a sample of 102 patients, their primary caregivers, and 15 members of the healthcare staff evaluated patients’ QoL (QoL-AD Scale). Patients’ and caregivers’ demographic and clinical data (cognitive function, neuropsychiatric symptoms, depression, and caregivers’ burden) were considered as QoL predictors.

Results: In multivariate-adjusted linear regression analyses, we observed that patients’ ratings were mainly affected by their mood whereas caregivers’ ratings were also negatively influenced by patients’ irritability and burden. According to staff ratings, both psychotic symptoms and neuroleptics were associated with lower QoL.

Conclusions: Our findings suggest that depression is the main variable related to patients’ QoL and that more careful management of neuropsychiatric disorders is necessary. Both proxies’ ratings are not equivalent to patients’ reports in terms of predictors but they are complementary. Thus, a thorough QoL assessment should consider separately the perspective of the different informants.