A questionnaire-based survey on hyperphagia in individuals with Prader–Willi syndrome in Japan

Prader-Willi syndrome (PWS) is associated with increased mortality, primarily due to complications from hyperphagia-associated obesity. Clinical trials investigating anti-hyperphagic medications are currently underway. The Hyperphagia Questionnaire for Clinical Trials (HQ-CT) is designed to assess hyperphagia in PWS, with scores ranging from 0 to 36, where higher scores indicate greater severity. However, HQ-CT scores have not yet been evaluated in Japan. Therefore, we conducted a questionnaire-based survey among patient association members. Of 605 members, the score was available in 266. Their median age was 13 years (range: 0-48). Of these, 160 were children (<18 years), and 106 were adults (≥18 years). Obesity was observed in 11% and 40% of the pediatric and adult participants, respectively. The genetic subtypes included deletions (56%) and uniparental disomies (26%). The median HQ-CT score was 5 (range: 0-30), with no significant differences observed by sex or genetic subtype. The adult participants had significantly higher scores than pediatric participants (8 vs. 4). The HQ-CT score was lower than that reported in studies conducted overseas. Among adult participants, the score was significantly higher in obese individuals than in non-obese individuals, and multivariate analysis demonstrated a positive association between the score and body mass index, after adjusting for age, sex, genotype, and growth hormone treatment during childhood (β = 0.38, p = 0.0001). However, no such association was observed in pediatric participants. These findings provide valuable insights into the hyperphagic status of PWS in Japan and implicate that hyperphagia imposes a disease burden, particularly during adulthood.