Research Article: Psychometric properties of the novel patient-reported Functional Impacts of Narcolepsy Instrument (FINI) using data from phase 3 clinical trials in narcolepsy type 1
Abstract:
The Functional Impacts of Narcolepsy Instrument (FINI) is a 28-item patient-reported outcome measure developed to evaluate key functional impacts in people with narcolepsy type 1 (NT1) and 2 (NT2) across 6 domains: Tiredness, Cognitive Functioning, Cataplexy, Social Activities, Everyday Activities, Everyday Responsibilities. This study aimed to assess the FINI's psychometric properties and estimate meaningful within-patient change (MWPC) thresholds in NT1 using pooled data from 2 phase 3 clinical trials evaluating oveporexton in NT1 ( N = 167, NCT06470828; N = 105, NCT06505031).
FINI scale structure, known-groups validity, convergent/divergent validity, internal consistency reliability, test-retest reliability, and responsiveness were evaluated. MWPC thresholds were estimated using anchor- and distribution-based approaches.
Confirmatory factor analysis supported the FINI 6-domain scale structure. The domains demonstrated good known-groups validity, especially for comparisons between severe and moderate reference measure groups (most P -values < 0.05, standardized effect sizes: 0.3–0.9). Convergent/divergent validity was supported by agreement between observed and expected correlation coefficients between FINI domains and reference measures. Most domains demonstrated good internal consistency (Cronbach's alpha: 0.63–0.90; ?0.78 for all except Everyday Activities). Excellent test-retest reliability was observed for all domains in a subpopulation of participants with a stable condition based on self-reported Patient Global Impression of Severity scores (ICC ?0.70). Good responsiveness was demonstrated for all FINI domains, supported by correlations between domain and continuous reference measure change scores >0.35, and with greater improvements in domain scores associated with greater categorical improvements in reference measures (all P -values <0.05, average between-group standardized response mean across domains: 0.69). All prespecified anchors exceeded the a priori threshold correlation with FINI domains (?0.30) and were used to derive MWPC thresholds (ranges): Tiredness and Everyday Activities, ?35 (?30 to ?40); Cognitive Functioning and Everyday Responsibilities, ?30 (?25 to ?35); Social Activities, ?25 (?20 to ?30); and Cataplexy, ?20 (?15 to ?25).
The FINI is a robust and valid measure assessing meaningful and important key functional impacts for people with narcolepsy. These findings support use of the instrument in clinical trials to evaluate treatment benefit in NT1. Given the FINI's sensitivity to change, it can potentially facilitate treatment decisions and track longitudinal outcomes in clinical practice.
Introduction:
The Functional Impacts of Narcolepsy Instrument (FINI) is a 28-item patient-reported outcome measure developed to evaluate key functional impacts in people with narcolepsy type 1 (NT1) and 2 (NT2) across 6 domains: Tiredness, Cognitive Functioning, Cataplexy, Social Activities, Everyday Activities, Everyday Responsibilities. This study aimed to assess the FINI's psychometric properties and estimate meaningful within-patient change (MWPC) thresholds in NT1 using pooled data from 2 phase 3 clinical trials…
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