Patient-reported outcome measure for neuromyelitis optica: pretesting of preliminary instrument and protocol for further development in accordance with international guidelines.

Abstract

ObjectiveThis study outlines the development of a patient-reported outcome measure (PROM), an instrument to obtain self-reported health status for neuromyeltis optica (NMO), a disabling neurological condition.DesignDevelopment was conducted in accordance with international guidance for PROMs including systematic review of existing literature, item generation guided by qualitative interviews, health-related quality of life conceptual framework and clinical expert panel and cognitive interviews with NMO patients.SettingParticipants were identified through a national NMO clinic in a tertiary NHS neurosciences service.Participants15 individuals with NMO participated in cognitive interviews requiring review and ranking of proposed PROM items and qualitative feedback on content, layout and response options.ResultsParticipants endorsed the draft instrument as reflecting their experience of the condition and as being easy to understand. Rating and ranking of item relevance and importance reduced the draft instrument from 106 to 48 items. Participant feedback on overlapping items eliminated a further 2 items and resulted in a preliminary instrument of 46 items. As a direct result of participant feedback ordering of the 10 domains was revised, a 4 option Likert scale was employed and a 4-week recall period for impact of symptoms was selected.ConclusionsA 46-item instrument developed in accordance with international PROM development guidelines through literature review, developed by subject matter experts and refined through pretesting examining content validity provides a preliminary measure for assessing patient-report of health status in NMO. Further evaluation is proposed including sensitivity to clinical change, and international contributions to evaluating the measure are encouraged.