Validation of the Spanish version of the QoL-AD scale in Alzheimer disease patients, their carers, and health professionals

Abstract

BackgroundQuality of life (QOL) is becoming increasingly important to measure the effect of interventions on the life of patients with Alzheimer's disease (AD), particularly on the most meaningful issues. However, most of the instruments used to measure QOL have not been validated in the Spanish population. The aim of this study was to determine the psychometric properties of a Spanish version of QoL scale in patients with AD, carers and health professionals. Material and methodsOn hundred and two patients, their carers and 25 health professionals were recruited from day centres. Patients’ QOL was rated by patients, carers and health professionals. The Health Utilities Index, Clinical Insight Rating Scale and Mini Mental State Examination were also administered. ResultsThe internal reliability and external reliability of QoL-AD were excellent. Criterion validity was indicated by a significant correlation of QoL-AD scores with HUI-3 and QoL-AD global item scores (P<.05). Lack of insight and cognitive impairment did not have an effect on these properties. QoL-AD scores were not significantly different between groups made according sociodemographic characteristics and cognitive impairment (P>.05). The exploratory factor analysis result revealed a three factor solution, which accounted for 61.3% of variance: health factor, functional status factor, and social relationship–environment factor. ConclusionsQoL-AD scale has proved to be a valid and reliable instrument to measure QoL of Spanish AD patients with mild-to-moderate cognitive impairment and a wide range of anosognosia.