Testing the EQ-HWB-9 with seven-day versus today recall periods in dementia: variability and recall adherence under health fluctuations.

To compare a "7-DAY" and "TODAY" recall period of the EQ-HWB-9 in people living with dementia (PlwD) with regard to day-to-day health changes (health fluctuations) and recall period adherence.

In this mixed-methods study, PlwD-caregiver dyads from German primary care were randomized to complete the EQ-HWB-9 (self- and proxy-proxy report) using either a "7-day" or "today" recall period over a two-week time period on day 1, day seven and day 14. In addition, caregivers recorded daily health fluctuations over 14 days via a diary. Health fluctuations were examined in relation to EQ-HWB-9 score variability and recall adherence, which was assessed via semi-structured caregiver interviews. Quantitative analyses included recall group comparisons, effect sizes, and variance analyses.

Seventy-four dyads were included (PlwD mean age 77 years; 41.9% female; caregiver mean age 71 years; 71.6% female). Proxy EQ-HWB-9 scores were higher (worse health) than self-reports and higher with the "7-day" versus "today" recall. Caregivers reported at least one health fluctuation in 92% of PlwD; fluctuations occurred in 41% of daily assessments. Greater diary-documented fluctuation was associated with higher EQ-HWB-9 score variability. Recall adherence differed by health fluctuation status: caregivers of PlwD with no to low health fluctuations favored TODAY, whereas those of PlwD with high health fluctuations favored the 7-DAY recall time frame.

No single recall period appears optimal for all PlwD. Recall period selection should consider individual health fluctuation patterns to improve the performance of HRQoL assessments in dementia.

People living with dementia (PlwD) often experience recurrent, often unpredictable, day-to-day changes in their health, with some days better (e.g. better memory), others worse (e.g. aggressive behaviour), so-called health fluctuations. Measuring the quality of life in PlwD has become an essential goal in the treatment and research of dementia. Nevertheless, it is unknown how quality-of-life questionnaires can capture these day-to-day changes in PlwD across different recall periods. In our study, we compared a "7-day" recall period with a “today” recall period using the EQ-HWB-9 questionnaire, an instrument of health and well-being. PlwD and their caregivers completed the questionnaire over 2 weeks, on days 1, 7, and 14. At the same time, caregivers kept a daily diary documenting whether the PlwD’s health had improved, worsened, or stayed the same compared to the previous day. We found that health fluctuations were very common: caregivers reported to perceive at least one change in most of PlwD, which are often related to exhaustion, depression and cognitive changes. We also found that caregivers who document no to low health fluctuations are more likely to use the today recall period than those who report greater day-to-day changes in PlwD. These caregivers often adhere to the 7-day recall time frame. We conclude that the choice of recall periods matters. In conditions like dementia, where health can change frequently, selecting an appropriate recall period is essential for accurately capturing quality of life.