A new international survey led by the International Osteoporosis Foundation reveals that adults living with hypophosphataemic osteomalacia (HO), a rare metabolic bone disorder, face a substantial and often under-recognised disease burden, with wide variation in how the condition is managed worldwide.

With its findings published in Archives of Osteoporosis, the survey gathered insights from the global IOF network. Responses were received from 40 clinicians across 24 countries who collectively manage more than 1,000 adult patients with HO. The majority of the cases reported were for the more common HO disorders: 35% with X-linked hypophosphataemia (XLH), 24% with tumour-induced osteomalacia (TIO), and 16% with fibrous dysplasia/McCune-Albright syndrome (FD/MAS).

The survey findings show:

• Patients commonly experience debilitating musculoskeletal symptoms, including bone pain, muscle weakness, and mobility limitations, all of which significantly impact quality of life and the ability to work.
• Many patients with XLH, the most common inherited HO disorder, had discontinued phosphate and vitamin D therapies, with a subset initiating burosumab treatment.
• In contrast, phosphate and vitamin D therapies were commonly used in TIO, with many patients being considered for tumour resection and limited burosumab use.
• Use of pain medications, including opiates, was relatively high across all patients.
• Despite available treatments, management approaches varied considerably depending on diagnosis, geography, and access to specialist care.

“Adults with hypophosphataemic osteomalacia experience a considerable and persistent burden of disease that is often underestimated,” said Professor Maria Luisa Brandi, lead author of the study. “The rarity of these HO disorders, combined with non-specific and overlapping symptoms, often leads to delayed or missed diagnosis – indeed, most non-specialist physicians are unlikely to encounter enough cases to develop substantial clinical expertise. In addition, the transition from paediatric to adult care can bring further challenges for patients.”

“Our survey findings highlight the need for improved awareness of these conditions beyond specialist centres, as well as more consistent, multidisciplinary approaches to care to ensure that more patients receive timely diagnosis and optimal treatment.”

The authors call for increased efforts to educate healthcare professionals, particularly in primary care settings, and to strengthen multidisciplinary care models involving endocrinologists, rheumatologists, orthopaedic surgeons, and other specialists. They also highlight the importance of future research to better understand regional differences in care, and to prioritise patient-centred outcomes such as pain management and mobility.

Professor Nicholas Harvey, President of the IOF and co-author of the study, emphasized the broader implications: “The findings of the survey demonstrate the vital role of global collaboration in understanding rare diseases of the musculoskeletal system. By leveraging the IOF network, which includes healthcare professionals in all world regions, we can identify gaps in care and work towards improving education, diagnosis, and treatment pathways for patients with these rare and challenging-to-treat disorders.”

As awareness grows and treatment options continue to advance, the study provides a crucial foundation for improving outcomes for adults living with hypophosphataemic osteomalacia worldwide.

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Reference: Brandi, M. L., Halbout, P., Pierroz, D. D., & Harvey, N. C. (2026). Global perspectives on the burden and management of hypophosphataemic osteomalacia in adult patients: An International Osteoporosis Foundation (IOF) survey. Archives of Osteoporosis, 21, 61. https://doi.org/10.1007/s11657-026-01692-y

About IOF

The International Osteoporosis Foundation (IOF) is the world’s largest nongovernmental organization dedicated to the prevention, diagnosis, and treatment of osteoporosis and related musculoskeletal diseases. Its members — including committees of leading scientific researchers and 349 patient, medical, and research organizations across 152 countries — work together to make fracture prevention and healthy mobility a global healthcare priority.

https://www.osteoporosis.foundation   @iofbonehealth