Psychometric evaluation of novel hyperphagia questionnaires in a real-world setting for patients with a rare MC4R pathway disease.

Background: There are no validated measures to assess hyperphagia associated with rare MC4R pathway diseases, such as Bardet-Biedl Syndrome (BBS). Symptoms of Hyperphagia© (SoH) and Impacts of Hyperphagia© (IoH) are novel questionnaires designed to assess signs and symptoms of hyperphagia and their impacts on patients and caregivers. We evaluated the psychometric performance of the caregiver-versions of the SoH: Caregiver (Observer-reported) and IoH: Caregiver (Observer-reported and Self-reported subscales).

Results: Reliability and validity were evaluated using data from a multi-country cross-sectional survey of adult caregivers of patients with BBS experiencing hyperphagia and obesity. Other instruments included were Impact of Weight on Quality of Life (IWQOL)-Kids (Parent Proxy), PROMIS Scale Global Health of Caregiver, Revised Impact on Family Scale (RIOFS), and Work Productivity and Activity Impairment. 242 eligible caregivers completed the survey. Exploratory factor analysis identified 1 factor per subscale. Strong internal consistency was observed for IoH: Caregiver (Observer) (Cronbach's a = 0.66) and IoH: Caregiver (Self) (a = 0.72) and moderate for SoH: Caregiver (Observer) (a = 0.40). Moderate-to-strong correlations were observed with school days missed and all domains of IWQOL-Kids except Physical Comfort (range = 0.315-0.573, p's < 0.001). Known-groups indicated significantly worse SoH: Caregiver subscores for patients using appetite suppressants or implementing more weight management approaches (6-10 vs. ≤5 or > 10). Caregivers reporting greater strain on RIOFS items and worse mental health had worse IoH subscores.

Conclusions: The SoH: Caregiver and IoH: Caregiver demonstrated preliminary validity, reliability, and consistency in a real-world setting. Research is underway to further validate these measures for use in clinical trials for BBS and other MC4R pathway-related diseases associated with obesity.