Bone Abstracts

Objectives: XLH is a rare, genetic, inherited disorder characterised by low blood phosphate which leads to inadequate mineralisation of bone, resulting in a spectrum of skeletal and functional muscle abnormalities, abnormal tooth development, physical and functional impairments. Treatment with conventional therapy places a significant burden on patients and families; it can require complex treatment dosage schedules, is often poorly tolerated, and can be associated with serious complications. The aim of this study was to qualitatively analyse the burden of XLH in children and adolescents as reported in patient and caregiver testimonies.

Methods: During an appraisal of a new treatment for XLH conducted by the National Institute for Health and Care Excellence (NICE), a public consultation was undertaken in which 93 testimonies were provided by patients, their families, healthcare providers and other stakeholders on the burden of the condition. Hybrid deductive and inductive thematic analysis was used to analyse 41 testimonies related to children or adolescents with XLH. Two reviewers independently coded and analysed the responses according to 12 themes, with differences settled through third party consensus.

Results: The majority of consultation responses were from parents of affected individuals. The experiences revealed symptoms associated with XLH, including bone deformities and short stature, were frequently related to general pain and mental well-being (stress). Short stature was often expressed alongside experiences of bullying and low self-esteem. Conventional treatment in childhood, typically a complex multi-daily dose regimen of oral phosphate and Vitamin D, was a common complaint for patients and placed strains on their families. Dosing regimen, non-adherence, taste and adverse effects were most likely to be related to treatment burden with conventional therapy. The treatment burden theme was highly associated with families with multiple children with the strain of medication administration.

Conclusion: Our findings indicate the burden of illness in XLH in this age group is multi-factorial. Symptoms related to skeletal complaints suggest certain themes are organically-driven by functional impairments, while complaints in the burden of treatment also have a notable psychological and wider family impact. Qualitative analysis of XLH can inform the understanding of the burden of disease from the patient perspective.

Disclosure: NF, CM, JM, NS and ZM have been funded by Kyowa Kirin.