Health Fluctuations in Dementia and its Impact on the Assessment of Health-related Quality of Life using the EQ-5D-5L.

OBJECTIVES: To quantify health fluctuations, identify affected health-related quality of life (HRQoL) dimensions, and evaluate if fluctuations affect the HRQoL instruments recall period adherence in people living with dementia (PlwD).

METHODS: Caregivers of PlwD completed a daily diary for 14 days, documenting if PlwD's health was better or worse than the day before and the affected HRQoL dimensions. Health fluctuation was categorized into low (0-4 fluctuations in 14 days), moderate (5-8) and high (9-14). Also, caregivers and PlwD completed the EQ-5D-5L (proxy- & self-reported) on days one, seven, and 14. Subsequently, caregivers were interviewed to determine whether recurrent fluctuations were considered in the EQ-5D-5L assessment of today's health (recall period adherence).

RESULTS: Fluctuations were reported for 96% of PlwD, on average, for 7 of the 14 days. Dimensions most frequently triggering fluctuations included memory, mobility, concentration, sleep, pain, and usual activities. Fluctuations were associated with higher EQ-5D-5L health states variation and non-adherence to the EQ-5D-5L recall period 'today'. PlwD with moderate to high fluctuation had the highest EQ-5D-5L utility change between day one and fourteen (0.157 and 0.134) and recall period non-adherence (31% and 26%) compared to PlwD with low fluctuation (0.010; 17%). Recall period non-adherence was higher in PlwD with improved than in those with deteriorated health in the diary (37% vs. 9%).

CONCLUSION: Health fluctuations frequently occur in dementia and strongly affect HRQoL assessments. Further research is needed to evaluate if more extended recall periods and multiple, consecutive assessments could capture health fluctuations more appropriately in dementia.