# Real-world characteristics & disease history of patients with X-linked hypophosphatemia before treatment with burosumab

## TL;DR

This study examines health issues in patients with X-linked hypophosphatemia before they start treatment with burosumab, showing significant disease burden across all ages.

## Contribution

The study provides real-world evidence of XLH-related morbidities in patients before burosumab treatment initiation in the U.S.

## Key findings

- High prevalence of XLH-related morbidities was observed, increasing with age.
- Arthralgia and opioid use were common across age groups, with higher rates in older patients.
- Over half of patients initiating burosumab were under 18 years old.

## Abstract

In a United States claims database, 1,358 persons with familial hypophosphatemia who began treatment with burosumab were identified. Prior to treatment, high rates of several morbidities were coded including osteoarthritis, fractures, enthesopathy, spinal stenosis, hypertension, depression and opioid use, which generally increased with age, emphasizing disease burden throughout the lifespan.

To examine the characteristics and disease history of real-world patients with X-linked hypophosphatemia (XLH) in the United States, prior to initiating burosumab.

This retrospective cohort study used Komodo Health’s Healthcare Map™, a de-identified patient-level claims database. Included patients had ≥ 1 claim for familial hypophosphatemia between 01-Jan-2015 and 30-Jun-2022 (the study period) and ≥ 1 claim for burosumab between 01-Apr-2018 and 30-Jun-2022. The index date was the date of first burosumab claim. Patient demographics were measured at index; disease history was measured over the pre-index period and stratified by age. All variables were evaluated descriptively.

1,358 patients were included (mean age 23.5 ± 19.1 years, 847 [62%] female); 720 patients (53%) were aged < 18 years. Prior to index, patients had high levels of XLH-related morbidities. Most XLH-related morbidities appeared in the youngest age groups, and the prevalence was generally greater among the older age groups. For example, arthralgia was found in 57 patients (12%) aged ≤ 11 years and 123 patients (69%) aged ≥ 50 years. Opioid use increased with age (173 patients [24%] aged < 18 years; 328 [51%] ≥ 18 years). Physical therapy use was observed across age groups (126 patients [18%] aged < 18 years; 253 [40%] ≥ 18 years).

At initiation of burosumab, over half of patients with XLH were < 18 years of age. Claims indicated a high prevalence of XLH-related morbidities, which began at a young age and increased over time.

The online version contains supplementary material available at 10.1007/s11657-025-01544-1.