Pain Medication Use in Patients With X-Linked Hypophosphatemia Treated With Burosumab: a Retrospective Real-world Study

Abstract X-linked hypophosphatemia (XLH) is a rare, progressive phosphate-wasting disorder that leads to significant skeletal morbidities and pain. The current study used real-world administrative claims data to assess demographic and clinical characteristics of patients with XLH related to claims for prescription pain medication (PPM) during the 12 months before starting burosumab treatment (baseline) and explores changes in PPM claims after starting burosumab treatment. Claims for XLH-related musculoskeletal and deformity-related conditions, obesity, and osteoarthritis were common among the adult cohort (n=387). Claims for PPM (vs no claims) during baseline were significantly (p<0.05) associated with: age ≥50 years (odds ratio [OR] 2.54), Medicaid coverage (2.25), myalgia (2.54), scoliosis (3.19), obesity (2.07), dental complications (2.53), and physical therapy (2.94). Approximately half of the adult cohort (54%) made PPM claims during baseline, and 38% for opioids, with little change after starting burosumab. Claims for arthralgia, hip/leg deformities and rickets were common in pediatric patients (n=524). Claims for PPM were significantly associated with race (OR 0.13), chronic pulmonary disease (4.34), renal disease (4.88), arthralgia (2.20), cholecalciferol claims (1.93), and physical therapy (3.48). About one-fifth of pediatric patients (25%) had claims for PPM prescriptions during baseline, with little change after 12 months but a modest decrease during the second year of follow-up; 12–17% of pediatric patients had claims for opioids during baseline and follow-up. The number of days covered by opioid prescriptions was lower in pediatric patients than in adults. Multiple factors are associated with PPM use in patients with XLH. Understanding these factors may inform patient-centered pain management strategies. A longer study is needed to determine how burosumab treatment affects pain and use of PPM in patients with XLH.