Development of a novel patient reported outcome measure for health-related quality of life in amyotrophic lateral sclerosis (PROQuALS): study protocol.

Background: Patient reported outcome measures (PROMs) can be used to assess the impact of health conditions upon an individual's health-related quality of life (HRQoL). Whilst PROMs have been used to quantify the HRQoL impact of amyotrophic lateral sclerosis (ALS), existing instruments may not fully capture what matters to people living with ALS (plwALS) or be appropriate to be used directly to inform the cost-effectiveness of new treatments. This highlights a need for a new condition-specific PROM that can both capture what's important to plwALS and be used in economic evaluation. This study has two key aims: 1) to produce a novel PROM for measuring HRQoL in plwALS (PROQuALS). 2) to value a set of items from the novel PROM to generate an associated preference-weighted measure (PWM) that will enable utility values to be generated.

Methods: A mixed-methods study design will be conducted across three stages. Stage 1 involves concept elicitation and the generation of draft PROM content from a robust and comprehensive systematic review of HRQoL in ALS, with input from plwALS. Stage 2 consists of cognitive debriefing of the draft PROM content to ascertain its content validity (Stage 2a), followed by a psychometric survey (Stage 2b) to assess statistical performance. Evidence from Stage 2 will be used to make decisions on the final content and format of the novel PROM. Stage 3 will involve valuation and econometric modeling using health economics methods to generate preference weights, so a PWM derived from the novel PROM can be used in the cost-effectiveness analyses of treatments. Patient and clinical advisory groups will have critical, collaborative input throughout the project.

Discussion: The novel PROM will be designed to comprehensively assess important aspects of HRQoL to plwALS and to quantify HRQoL in terms of subjective impact. The PROQuALS measure will be available for use in research and healthcare settings. The associated PWM component will extend and enable the use of PROQuALS in cost-effective analyses of new treatments for ALS.

Trial Registration: Not applicable.