MON-863 - Mortality Among Patients with Prader-Willi Syndrome (MAP-PWS): An Analysis of Healthcare Utilization in the Year Prior to Death within A Single U.S. Payer

Objectives:
Prader-Willi syndrome (PWS) is a complex genetic disorder characterized by cognitive and behavioral challenges, developmental disability, endocrine abnormalities, and chronic, life-threatening hyperphagia. Individuals with PWS show heightened hyperphagia-related mortality contributing to one-third of reported U.S. PWS deaths (Butler et al., 2017). To better understand current mortality in PWS, we evaluated recent medical claims to assess age-adjusted mortality rate and characterize healthcare resources accessed in the year prior to death.

Methods:
We analyzed de-identified U.S. medical claims for individuals with PWS (defined as having ≥2 claims with Q87.11 code) between January 2020 and March 2025. Those with a confirmed date of death had the 12-month period preceding death examined to evaluate healthcare resource utilization. Utilization included visits with specialists commonly involved in PWS care (endocrinologists, mental health providers, pulmonologists, cardiologists) and encounters at acute care facilities (emergency department visit or hospitalization). Mortality rates were adjusted for age and person-time for the PWS cohort (reported per 100,000 patient-years). National mortality rates were obtained for comparison using CDC 2024 data. All analyses were descriptive.

Results:
Among 688 patients with PWS, 18 deaths were identified, of whom 12 (67.7%) were Medicaid enrollees. The age-adjusted mortality rate was 773.1 per 100,000 patient-years, with a mean age at death of 32.3 years (range 5-98). In comparison, the age-adjusted mortality rate for the overall U.S. population was 134.6 per 100,000 patient-years. In the 12 months preceding death, patients averaged 25.1 (SD 38.1, median 5) specialist visits and 4.2 (SD 7.5, median 2) encounters at acute care facilities; of these, 29.9% and 24.0%, respectively, occurred in the final month of life. As a group, 72.2% had ≥ 1 specialist visit and 77.8% had ≥ 1 acute care facility encounter. Three patients had no claims for either service type in this period.

Conclusions:
Individuals with PWS are at risk of premature death. The mortality rate among patients in this PWS cohort was nearly six times higher than what would have been expected of the general population of similar age distribution. Over a quarter of encounters occurred in the month preceding death, indicating an increase in healthcare utilization during that last month and may suggest a more rapid decline prior to death. Future analysis is needed to assess contributory and precipitating risk factors for death and to further identify how to improve care delivery to this population. Through this detailed examination, we hope to find health care patterns leading to recommendations for health surveillance and interventions to improve mortality outcomes for this population.

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