Good Days and Bad Days: Measuring Health-Related Quality of Life in People With Epilepsy

EPISODE-team, Job van Exel

Research output: Contribution to journalArticleAcademicpeer-review

2 Citations (Scopus)


Objectives: Cost-effectiveness analyses typically require measurement of health-related quality of life (HRQoL) to estimate quality-adjusted life-years. Challenges with measuring HRQoL arise in the context of episodic conditions if patients are less likely—or even unable—to complete surveys when having disease symptoms. This article explored whether HRQoL measured at regular time intervals adequately reflects the HRQoL of people with epilepsy (PWE). Methods: Follow-up data from the Epilepsy Support Dog Evaluation study on the (cost-)effectiveness of seizure dogs were used in which HRQoL is measured in 25 PWE with the EQ-5D at baseline and every 3 months thereafter. Seizure count is recorded daily using a seizure diary. Regression models were employed to explore whether PWE were more likely to complete the HRQoL survey on a good day (ie, when seizures are absent or low in frequency compared with other days) and to provide an estimate of the impact of reporting HRQoL on a good day on EQ-5D utility scores. Results: A total of 111 HRQoL measurements were included in the analyses. Regression analyses indicated that the day of reporting HRQoL was associated with a lower seizure count (P<.05) and that a lower seizure count was associated with a higher EQ-5D utility score (P<.05). Conclusions: When HRQoL is measured at regular time intervals, PWE seem more likely to complete these surveys on good days. Consequently, HRQoL might be overestimated in this population. This could lead to underestimation of the effectiveness of treatment and to biased estimates of cost-effectiveness.

Original languageEnglish
Pages (from-to)1470-1475
Number of pages6
JournalValue in Health
Issue number10
Publication statusPublished - 2021

Bibliographical note

Funding Information:
The primary data were extracted from a study funded by The Netherlands Organisation for Health Research and Development (ZonMw, grant no. 843005002 ). Additional funding for conducting this analysis was provided by the Innovation fund health insurers Netherlands (Zorgverzekeraars Nederland).

Publisher Copyright:
© 2021 ISPOR–The Professional Society for Health Economics and Outcomes Research


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