Producing a preference-based quality of life measure for people with Duchenne muscular dystrophy: a mixed-methods study protocol.

Abstract

Preference-based measures (PBMs) of health-related quality of life (HRQoL) are used to generate quality-adjusted life years, which are necessary for cost-effectiveness evaluations of health interventions via cost-utility analysis. These measures of health can be generic (ie, pandiagnostic) or condition specific. No condition-specific PBM of HRQoL in Duchenne muscular dystrophy (DMD) exists, yet there are concerns that standard generic measures lack the specificity to assess aspects of HRQoL that are especially important to people with DMD. This study has been designed to produce a condition-specific PBM of HRQoL in DMD. This mixed-methods study proceeds through three stages. In the first stage (concept elicitation), semistructured interviews will be conducted with boys and men diagnosed with DMD, and analysed with framework to produce a draft health state descriptive system for HRQoL in DMD. In the second stage (refining the descriptive system), patients, clinicians and primary caregivers of people with DMD will assess the face validity of the descriptive system. This will be followed by a quantitative survey on a larger sample of patients, which will be analysed with psychometric analyses to produce a refined descriptive system. In the third stage (valuation and econometric modelling), an online discrete choice experiment with duration will be administered to a general public sample to generate utility values for the new measure. This study has received ethical approval from the National Health Service (REC reference: 18/SW/0055). The primary output of this research will be a condition-specific PBM (or 'bolt-on' to an existing generic PBM) in people with DMD and an associated value set. Results will be disseminated through international conferences and open-access journals.