Psychometric of the Persian version of Quality of Life in Late-Stage Dementia (QUALID) in the elderly with Alzheimer's disease.

Background: Improving the quality of life (QoL) is a significant healthcare priority, and it is an important health outcome for elderly individuals with Alzheimer's disease. Quality of Life in Late-Stage Dementia (QUALID) is a specific scale used to measure the QoL in elderly individuals with Alzheimer's. So far, limited quantitative research has been conducted on the psychometric properties of this scale.

Aims: This study was conducted to translate the QUALID Scale into Persian and evaluate its psychometric properties among family and professional caregivers of elderly individuals with Alzheimer's disease in Tehran.

Methods: A cross-sectional methodological study was conducted among family and professional caregivers of elderly individuals with Alzheimer's in Tehran, Iran in 2022. The questionnaire was translated into Persian using the forward-backward method. Face and content validity were assessed. Additionally, construct validity was examined using exploratory factor analysis (EFA) with Equamax rotation (n=210) and confirmatory factor analysis (CFA) (n=155). Cronbach's alpha and interclass correlation coefficient (ICC) were estimated to determine reliability.

Results: A total of 365 caregivers with a mean age of 14.18±42.60 years participated in this study. In the face and content validity phase, all 11 items were retained. To determine the construct validity, two factors were extracted in the EFA phase, including behavioural signs of discomfort and behavioural signs of social interaction. The findings of the CFA also indicated that all goodness of fit indices supported the final model. The Cronbach's alpha was excellent for both factors (0.814), and the ICC was calculated as 0.98.

Conclusion: Based on the findings of this study, it can be concluded that the Persian version of the QUALID Scale has sufficient validity and reliability for measuring the QoL in elderly Iranian individuals with Alzheimer's.