The Estimation of Utility Weights From the Rett Syndrome Behavior Questionnaire
Author(s)
Hanna Skrobanski, BSc, MSc, PhD1, Caleb Dixon, MSc2, Dilesh doshi, PHARMD3, Mirko V. Sikirica, PHARMD4, Arya Pimprikar, MSc1, Andrew Lloyd, DPhil1.
1Acaster Lloyd, London, United Kingdom, 2Acaster Lloyd, Whitstable, United Kingdom, 3Acadia Pharmaceuticals, san diego, CA, USA, 4Sr. Director HEOR, Acadia Pharmaceuticals Inc., Berwyn, PA, USA.
1Acaster Lloyd, London, United Kingdom, 2Acaster Lloyd, Whitstable, United Kingdom, 3Acadia Pharmaceuticals, san diego, CA, USA, 4Sr. Director HEOR, Acadia Pharmaceuticals Inc., Berwyn, PA, USA.
OBJECTIVES: Rett Syndrome (RTT) causes loss of communication, gross motor function and hand function. Generic questionnaires, like the EQ-5D, may not adequately capture certain impacts of RTT. This study was conducted to develop utility-based scoring weights from the 45-item Rett Syndrome Behaviour Questionnaire (RSBQ), a disease-specific measure.
METHODS: Analysis of RSBQ data from the LAVENDER Clinical Trial (N=187) was conducted to assess item performance. Floor and ceiling effects, factor loading and descriptives identified poorly functioning items. An item review explored the relevance and suitability of items for valuation. A Discrete Choice Experiment (DCE) survey was conducted with the general public to elicit the importance of eight RSBQ items. Multinomial logit models estimated preference weights for item responses. Caregivers of RTT patients then rated the worst and best possible vignette states defined by RBSQ items, using the EQ-5D-5L. This was done to rescale the DCE preferences onto a 0-1 utility scale.
RESULTS: Eight RSBQ items were included in the DCE. Participants (n=290 UK and n=271 Canada) completed the DCE survey. Most attribute levels were statistically significant, indicating their relevance in participants' choices. Disutility weights for each level of each attribute were calculated using the DCE model coefficients rescaled against the worst and best health states, which ranged from 0.22 to 0.87. One item (“Using eye gaze to communicate feelings, needs and wishes”) was not included in the scoring function because of misordering.
CONCLUSIONS: RSBQ scoring weights (for Canada and the UK) allow for the estimation of utility values for RTT patients. Results showed that most attributes were significant independent predictors of choice, indicating their relevance to participants' decisions. Utilities offer the advantage of including potentially specific and sensitive items to assess the burden of RTT, but other aspects of quality of life not included in the RSBQ may affect the interpretation of data.
METHODS: Analysis of RSBQ data from the LAVENDER Clinical Trial (N=187) was conducted to assess item performance. Floor and ceiling effects, factor loading and descriptives identified poorly functioning items. An item review explored the relevance and suitability of items for valuation. A Discrete Choice Experiment (DCE) survey was conducted with the general public to elicit the importance of eight RSBQ items. Multinomial logit models estimated preference weights for item responses. Caregivers of RTT patients then rated the worst and best possible vignette states defined by RBSQ items, using the EQ-5D-5L. This was done to rescale the DCE preferences onto a 0-1 utility scale.
RESULTS: Eight RSBQ items were included in the DCE. Participants (n=290 UK and n=271 Canada) completed the DCE survey. Most attribute levels were statistically significant, indicating their relevance in participants' choices. Disutility weights for each level of each attribute were calculated using the DCE model coefficients rescaled against the worst and best health states, which ranged from 0.22 to 0.87. One item (“Using eye gaze to communicate feelings, needs and wishes”) was not included in the scoring function because of misordering.
CONCLUSIONS: RSBQ scoring weights (for Canada and the UK) allow for the estimation of utility values for RTT patients. Results showed that most attributes were significant independent predictors of choice, indicating their relevance to participants' decisions. Utilities offer the advantage of including potentially specific and sensitive items to assess the burden of RTT, but other aspects of quality of life not included in the RSBQ may affect the interpretation of data.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
PCR230
Topic
Clinical Outcomes, Methodological & Statistical Research, Patient-Centered Research
Topic Subcategory
Health State Utilities
Disease
Neurological Disorders, Pediatrics, Rare & Orphan Diseases