Oral Presentation ESA-SRB-APEG-NZSE 2022

Australian and New Zealand Paediatric Surveillance Units X-linked Hypophosphataemia survey: estimate of prevalence and characteristics of paediatric X-linked Hypophosphataemia in Australia and New Zealand. (#67)

Jessica L Sandy 1 , Carlos Nunez Miranda 2 , Anne Morris 2 3 , Danielle Handel 2 , Craig Jefferies 4 , Sonya Aum 5 , Peter J Simm 6 , Christine P Rodda 7 , Aris Siafarikas 8 , Andrew Biggin 1 , Christie-Lee Wall 1 , Ben Wheeler 5 , Craig F Munns 9 10
  1. The Children's Hospital At Westmead, Annandale, NEW SOUTH WALES, Australia
  2. Australian Paediatric Surveillance Unit, Sydney, NSW, Australia
  3. Sydney Children's Hospital, Randwick, NSW, Australia
  4. Children's Hospital at Westmead Clinical School, University of Sydney, Sydney, NSW, Australia
  5. Dunedin School of Medicine, University of Otago, Dunedin North, Dunedin, New Zealand
  6. Endocrinology and Diabetes, Royal Children's Hospital, Melbourne, VIC, Australia
  7. Dept of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
  8. Dept of Endocrinology and Diabetes, Perth Children's Hospital, Perth, WA, Australia
  9. Paediatrics, University of Queensland, Brisbane, NSW, Australia
  10. Endocrinology and Diabetes, Queensland Children's Hospital, Brisbane, NSW, Australia

Australian and New Zealand Paediatric Surveillance Units (APSU/NZPSU), which facilitate active surveillance of rare childhood diseases, conducted prospective data collection to review prevalence and characteristics of paediatric XLH in Australia (Aust) and New Zealand (NZ).

 

Seventy-five cases in Aust and 16 cases in NZ were identified with 60 completing a follow-up survey in Aust. Of the 91 cases overall, 46% were on burosumab therapy.

 

Clinical, demographic and management data are summarised in the Table. These demonstrate that despite a family history in the majority of cases, delayed diagnosis is common and there is a high rate of complications of nephrocalcinosis and hyperparathyroidism in this cohort. Additionally, while guidelines stress the importance of multidisciplinary care, many do not have access to recommended health professionals, with only 3% seeing a psychologist and 68% seeing a dentist. This is despite the high psychological burden of XLH and a significant proportion of this cohort having dental issues (tooth abscess, dental capping, tooth extraction).

 

There was a significant number of orthopaedic interventions performed. Of the 60 follow-up cases, 31 had undergone at least one orthopaedic procedure. Three cases reported cancellation of orthopaedic surgery due to improvement in lower limb deformity after commencement of burosumab.

 

Consistent with clinical trials, those on burosumab had a higher phosphate (p<0.001) at most recent follow-up.

 

Conclusions: These data suggests the estimated minimum prevalence of  XLH <18y is 1.31 and 1.6 per 100,000(95%CI 1.02 – 1.64) in Aust and NZ respectively. Burosumab is a promising new alternative to conventional therapy, but does not negate the need for multidisciplinary care.  These data highlights the lack of access to many health professionals, especially psychological support, for many children with XLH.

 

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