Brendan Mulhern1, Joshua Pink2, Donna Rowen3, Simon Borghs4, Thomas Butt5, Dyfrig Hughes6, Antony Marson7, John Brazier3. 1. Centre for Health Economics Research and Evaluation, University of Technology Sydney, Sydney, New South Wales, Australia; School of Health and Related Research, University of Sheffield, Sheffield, South Yorkshire, UK. Electronic address: Brendan.mulhern@chere.uts.edu.au. 2. Warwick Medical School, University of Warwick, Coventry, West Midlands, UK. 3. School of Health and Related Research, University of Sheffield, Sheffield, South Yorkshire, UK. 4. UCB Pharma, Slough, Berkshire, UK. 5. UCB Biopharma, Brussels, Belgium. 6. Centre for Health Economics and Medicines Evaluation, Bangor University, Bangor, Gwynedd UK. 7. Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, Merseyside UK.
Abstract
BACKGROUND: There is debate about the psychometric characteristics of the three-level EuroQol five-dimensional questionnaire (EQ-5D-3L) for use in epilepsy. In response to the concerns, an epilepsy-specific preference-based measure (NEWQOL-6D) was developed. The psychometric characteristics of the NEWQOL-6D, however, have not been assessed. OBJECTIVES: To investigate the validity and responsiveness of the EQ-5D-3L and the Quality of Life in Newly Diagnosed Epilepsy Instrument-six dimensions (NEWQOL-6D) for use in the assessment of treatments for newly diagnosed focal epilepsy. METHODS: The analysis used data from the Standard And New Antiepileptic Drugs trial including patients with focal epilepsy. We assessed convergent validity using correlations, and known-group validity across different epilepsy and general health severity indicators using analysis of variance and effect sizes. The responsiveness of the measures to change over time was assessed using standardized response means. We also assessed agreement between the measures. RESULTS: There was some level of convergence and agreement between the measures in terms of utility score but divergence in the concepts measured by the descriptive systems. Both instruments displayed known-group validity, with significant differences between severity groups, and generally slightly larger effect sizes for the NEWQOL-6D across the epilepsy-specific indicators. Evidence for responsiveness was less clear, with small to moderate standardized response means demonstrating different levels of change across different indicators. CONCLUSIONS: There was an overall tendency for the NEWQOL-6D to better reflect differences across groups, but this does not translate into large absolute utility differences. Both the EQ-5D-3L and the NEWQOL-6D show some evidence of validity for providing utility values for economic evaluations in newly diagnosed focal epilepsy.
BACKGROUND: There is debate about the psychometric characteristics of the three-level EuroQol five-dimensional questionnaire (EQ-5D-3L) for use in epilepsy. In response to the concerns, an epilepsy-specific preference-based measure (NEWQOL-6D) was developed. The psychometric characteristics of the NEWQOL-6D, however, have not been assessed. OBJECTIVES: To investigate the validity and responsiveness of the EQ-5D-3L and the Quality of Life in Newly Diagnosed Epilepsy Instrument-six dimensions (NEWQOL-6D) for use in the assessment of treatments for newly diagnosed focal epilepsy. METHODS: The analysis used data from the Standard And New Antiepileptic Drugs trial including patients with focal epilepsy. We assessed convergent validity using correlations, and known-group validity across different epilepsy and general health severity indicators using analysis of variance and effect sizes. The responsiveness of the measures to change over time was assessed using standardized response means. We also assessed agreement between the measures. RESULTS: There was some level of convergence and agreement between the measures in terms of utility score but divergence in the concepts measured by the descriptive systems. Both instruments displayed known-group validity, with significant differences between severity groups, and generally slightly larger effect sizes for the NEWQOL-6D across the epilepsy-specific indicators. Evidence for responsiveness was less clear, with small to moderate standardized response means demonstrating different levels of change across different indicators. CONCLUSIONS: There was an overall tendency for the NEWQOL-6D to better reflect differences across groups, but this does not translate into large absolute utility differences. Both the EQ-5D-3L and the NEWQOL-6D show some evidence of validity for providing utility values for economic evaluations in newly diagnosed focal epilepsy.
Authors: Ben F M Wijnen; Iris Mosweu; Marian H J M Majoie; Leone Ridsdale; Reina J A de Kinderen; Silvia M A A Evers; Paul McCrone Journal: Eur J Health Econ Date: 2017-09-04
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