THU394 Disease Burden Of X-Linked Hypophosphatemia Focused On The United States And Canada: A Targeted Literature Review
Authors: Li Zhiyi , Zaidi Omer , Chukwu Chinenye , Heerssen Heather , Zhao Yang , Dale Angie , Bernauer Mark 
Published: October 2023

Abstract
Disclosure: Z. Li: Employee; Self; Employee of Kyowa Kirin, Inc., Princeton, NJ, USA. O. Zaidi: Other; Self; Employee of OPEN Health and received funding to complete this research. C. Chukwu: Other; Self; Employee of OPEN Health and received funding to complete this research. H. Heerssen: Other; Self; Employee of Kyowa Kirin, Inc., Princeton, NJ, USA. Y. Zhao: Other; Self; Employee of Kyowa Kirin, Inc., Princeton, NJ, USA. A. Dale: Other; Self; Employee of Kyowa Kirin, Inc., Princeton, NJ, USA. M. Bernauer: Other; Self; Employee of OPEN Health and received funding to complete this research.
Introduction: X-linked hypophosphatemia (XLH) is a rare genetic musculoskeletal disease and the most common form of heritable hypophosphatemic rickets. The objective of this review was to summarize the disease burden and treatment patterns of XLH in the United States (US) and Canada. Methods: Publications from January 1, 2015, to June 3, 2022, were searched using the Medline, Embase, and EconLit databases. Observational studies reporting epidemiology, humanistic burden, economic burden, and treatment patterns in the US and Canada were included. Evidence on epidemiology, humanistic burden, and treatment patterns was expanded to other countries as limited US and Canada studies were identified. Results: A total of 1,218 publications were screened; 42 publications were included (6 from US or Canada; 36 did not report location or were from other countries). Epidemiology data (i.e., incidence, prevalence, mortality) were limited for patients with XLH in the US and Canada. The estimated number of people in the US with XLH was &lt;50,000 in 2021. Globally, the incidence of XLH was estimated at 3.9 per 100,000 live births, and the prevalence ranged from 1.4 per 100,000 to 4.8 per 100,000. One United Kingdom-based study estimated an XLH mortality rate of 12.1 per 1,000 person-years. Sixteen publications reported clinical manifestations of XLH, which showed a high level of heterogeneity. Among children with XLH, frequent clinical manifestations (&gt;80% in 1 or more publications) included active rickets, diminished height, gait disturbance, bone or joint pain, and leg bowing. Among adults with XLH, frequent clinical manifestations (&gt;80% in 1 or more publications) included short stature, leg deformity, musculoskeletal pain, fatigue, osteoarthritis, enthesophytes, gait disturbance, dental abscesses, and joint stiffness or restricted range of motion. Humanistic burden data from the US was limited to 2 non-trial publications, which used, respectively, the 36-Item Short Form Survey (SF-36) and the Knee Injury and Osteoarthritis Outcome Score-Physical Function Shortform (KOOS-PS) instruments. These 2 publications reported lower health-related quality of life for patients with XLH compared with the general population. No publication was identified on economic burden, treatment patterns, or XLH guidelines in the US or Canada. A consensus statement from a US panel of experts recommends individualization of monitoring and disease management due to clinical heterogeneity. Conclusions: There are limited published data on disease burden or treatment patterns for XLH in the US or Canada. Further research should consider the epidemiological, humanistic, and economic burden of XLH among pediatric and adult populations in these countries.
Presentation: Thursday, June 15, 2023