0455 The Insomnia Daytime Symptoms and Impacts Questionnaire: An Analysis of Clinically Meaningful Change Using Phase 3 Clinical Trial Data

Abstract

Abstract Introduction The Insomnia Daytime Symptoms and Impacts Questionnaire (IDSIQ) is a new validated patientreported outcome (PRO) instrument evaluating daytime functioning in people with insomnia. It comprises 14 items grouped into 3 domains: Alert/Cognition, Mood, and Sleepiness. To further explore the ability of the IDSIQ to capture clinically meaningful changes in daytime functioning resulting from treatment, we estimated withinsubject changes in IDSIQ scores using phase 3 trial data. Methods A randomized double-blind placebocontrolled trial of daridorexant in adults with insomnia (NCT03545191), in which subjects completed the IDSIQ daily during treatment, provided data for blinded analyses. Spearman correlations were calculated for changes in IDSIQ scores and potential anchors: Insomnia Severity Index, Patient Global Assessment of Disease Severity, Patient Global Impression of Severity, and Patient Global Impression of Change, applying a prespecified threshold of 0.30 (moderate association). Anchor-based analyses of weekly average IDSIQ total and domain scores were used to estimate responder definitions (RDs). The various RD estimates were triangulated to identify values where they converged. Distribution-based and receiver operating characteristic analyses calculated standard error of measurement (SEM), 0.5 standard deviation (SD), and Youden’s index as supportive evidence for anchor-based RD estimates. Results The analysis included 930 subjects (18-88 years). Score change correlations for the potential anchors and IDSIQ at month 1 (0.36–0.44) and month 3 (0.45–0.57) were all >0.30. Triangulation of mean IDSIQ score changes in subjects with clinically relevant improvement on the different anchors supported RD thresholds for clinically meaningful change of 17 points for the IDSIQ total score, 9 points for the Alert/Cognition domain, 4 points for the Mood domain, and 4 points for the Sleepiness domain. SEM and 0.5 SD values were within the ranges of anchor-based IDSIQ score changes, and Youden’s index was maximized or near-maximized when the RD estimates were used as thresholds for identifying responders based on the anchors. Conclusion The IDSIQ is sensitive to changes in patients who experience daytime impacts of insomnia and can be used to assess treatment efficacy on daytime functioning in patients with insomnia. Support (If Any) This work was funded by Idorsia Pharmaceuticals Ltd.