(76) Development of an Observer Reported Outcome (ObsRO) for Swelling Impact in Childhood Nephrotic Syndrome

Background: Fluid overload (FO), or swelling, in Nephrotic Syndrome (NS) impacts health-related quality of life (HRQOL). Partnering with Food and Drug Administration (FDA), Prepare-NS aims to create and validate a clinical outcome assessment (COA) set of swelling in NS for use in drug trials over the lifespan. The COA set will include an ObsRO for caregivers to report impact of swelling in young children.

Objectives: To develop a draft ObsRO measure that captures important aspects of swelling and its impact on function in young children with NS.

Design/Methods: Following informed consent, concept elicitation (CE) interviews occurred via Zoom or phone and discussed with participants how swelling from NS impacts functioning in their child. Interview transcripts were coded in NVivo by two independent raters according to established standards for qualitative analysis. Recurring themes informed the conceptual model. Draft ObsRO measure developed with questions capturing the recurring themes. Questions and response options submitted for translatability review. Additional individuals provided feedback on draft measures via cognitive debriefing (CogDe) interviews following informed consent/assent.

Results: 26 caregivers of young children age 2-11 with NS completed CE; 14 caregivers completed CogDe. Figure 1 summarizes demographics for participants and impacted children. Figure 2 presents representative quotations from CE. Figure 3 displays the proposed measurement model. CogDe of draft measure items showed excellent item comprehensibility (100%); item relevance varied by swelling severity. Modifications to the swelling impact measure (SIM) based on participant feedback outlined in Figure 4.

Conclusions: NS-SIM-ObsRO now will move forward into a validation study where caregivers of young children with NS and current swelling will complete surveys at enrollment, 3 months, and 9 months to establish psychometric properties of the SIM.