Abstract

Objectives

To assess the acceptability and validity of the 3 levels of the EQ-5D (EQ-5D-3L) compared with the Quality of Life in Alzheimer’s Diseases (QoL-AD) in patients living with dementia.

Methods

The analysis was based on 560 dyads of persons with dementia and their caregivers of the multicenter observational study of dementia care networks in Germany (DemNet-D). Health-related quality of life was assessed by face-to-face interviews using the EQ-5D-3L (self-rating) and the QoL-AD (self- and proxy-rating). The number of missing values, the score ranges (observed vs possible range) and the floor and ceiling effects were used to assess the acceptability. We used one-way analyses of variance and multivariate linear regression models to evaluate the discriminative ability. The convergent validity was assessed using Spearman's correlation coefficient (r ) and multivariate regression models.

Results

The EQ-5D index had a higher response rate (89% vs 84%) and a comparable floor (>1%) but a higher ceiling effect (18% vs >1%) compared with the QoL-AD. Both measures can significantly differentiate between different stages of general health, instrumental activities of daily living, and depression. The EQ-5D index and the visual analog scale self-rating scores strongly correlated with the QoL-AD self-rating (r = 0.644 and 0.553, respectively) but not with the proxy-rating score (r = 0.314 and r = 0.170, respectively), which was confirmed by multivariate regression analyses.

Conclusion

The results satisfy acceptability, discriminative ability, and convergent validity for moderately cognitively and functionally impaired patients living with dementia. The EQ-5D-3L performed comparably with the QoL-AD, and could, therefore, be used in economic evaluations in dementia. The differences between self- and proxy-ratings should be evaluated and considered in the interpretation of health-related quality of life scores.