Determining the Relationship of Seizures, Seizure-Free Days (SFDS) and Other Predictors of Health-Related Quality of Life (HRQOL) in Patients with Dravet Syndrome (DS) and Their Carers
Author(s)
Pinsent A1, Weston G1, Adams E2, Linley W3, Hawkins N4, Schwenkglenks M5, Hamlyn-Williams C6, Toward T7
1Aquarius Population Health, London, UK, 2Aquarius Population Health Limited, London, CAM, UK, 3Paragon Market Access Ltd, Chorley, UK, 4University of Glasgow, Glasgow, UK, 5European Center of Pharmaceutical Medicine - University of Basel, Basel, Switzerland, 6Aquarius Population Health, London, LON, UK, 7Zogenix International, Maidenhead, UK
OBJECTIVES : DS is a rare, early onset, lifelong epileptic encephalopathy characterised by frequent and severe seizures. High seizure frequency is associated with behavioral and physical developmental comorbidities with a substantial burden to patients’ and carers’ HR-QoL. Reducing convulsive seizure frequency and increasing SFDs is a primary treatment goal for patients. This study explored the impact of increasing SFDs on patients’ and carers’ HR-QoL. METHODS : In fenfluramine registration studies, patients (or proxies) completed the Pediatric Quality of Life Inventory. These patient HR-QoL data were mapped to EQ-5D-Y to provide patient utilities. Carer utilities were collected directly (EQ-5D) and mapped to EQ-5D-3L. A linear mixed effects regression model was developed to explore relationships between patient EQ-5D-Y, and clinically relevant variables: age group, frequency of SFDs per 28-days, motor impairment(s) and treatment dose. A linear panel regression model examined the relationship between SFDs and carer HR-QoL. RESULTS : Adjusting for age and underlying comorbidities, results from the patient regression model showed “frequency of SFDs per 28-days” was a significant predictor of HR-QoL (gain in EQ-5D utility of 0.005 per additional SFD, p<0.001). The carer linear panel model also showed “frequency of SFDs per 28-days” as a significant predictor of HR-QoL (gain in EQ-5D-3L utility of 0.014 per additional SFD, p<0.001). For example, a typical patient aged <6 years with 2 co-morbidities and 10 SFDs per 28-days would have an EQ-5D utility of 0.48. If on fenfluramine, SFDs increased to 20 or 28 (“seizure-free”) per 28 days, patient utility would rise 11.4% and 20.5%, and their carer’s utility by 27.7% and 49.8%, respectively. CONCLUSIONS : This regression framework provides a useful method in determining the HR-QoL impact that frequent seizures have on DS patients and their carers; highlighting that effective antiseizure treatments that durably increase SFDs, also improve patients’ and carers’ QoL in a directly quantifiable manner.
Conference/Value in Health Info
2021-05, ISPOR 2021, Montreal, Canada
Value in Health, Volume 24, Issue 5, S1 (May 2021)
Code
PND59
Topic
Economic Evaluation, Patient-Centered Research
Topic Subcategory
Cost-comparison, Effectiveness, Utility, Benefit Analysis, Health State Utilities, Patient-reported Outcomes & Quality of Life Outcomes
Disease
Drugs, Neurological Disorders