ESPE Abstracts (2014) 82 P-D-2-3-310

Bone (2)

Outcomes of Vitamin D Analogues and Phosphate Supplements in Patients With Hereditary Hypophosphatemic Rickets , Comparison With Non-Treated Patients

Emese Borosa, Anya Rothenbuhlerb, Claudine Heinrichsa, Cécile Bracheta, Laure Esterleb, Peter Kamenickyc, Pol Harvengtd, Sylvie Brailly-Tabarde, Hazar Haidare, Céline Gaucherf, Caroline Silveb, Charles Gossiomef, Philippe Wicartg, Martin Biosse Duplanf, Frederic Coursonf, Catherine Chaussainf & Agnès Linglartb


aService d’endocrinologie pédiatrique- Hôpital Universitaire des Enfants Reine Fabiola, Avenue J J Crocq 15, Bruxelles, Belgium; bCentre de Référence des Maladies Rares du Métabolisme du Calcium et du Phosphore, Service d’Endocrinologie et Diabétologie de l’Enfant, Université Paris Sud,Hôpital Bicêtre, APHP, 78 rue du Général Le, Paris, France; cCentre de Référence des Maladies Rares du Métabolisme du Calcium et du Phosphore, Université Paris Sud, Service d’Endocrinologie et Diabétologie, Hôpital Bicêtre, APHP, 78 rue du Général Leclerc 9427, Paris, France; dRepresentant association pour les personnes atteintes de rachitisme vitamino-résistant hypophosphatemique, Paris, France; eService de
Pharmacogénétique, Biochimie Moléculaire et Hormonologie, Service GMPH, Hôpital Bicêtre, APHP, Université Paris Sud, 78 rue du Général Leclerc 94270, Paris, France; fService d’odontologie Hôpital Bretonneau, HUPNVS, AP[hyphen]HP, EA 2496, UFR d’Odontologie Paris Descartes Sorbonne Paris Cité,, Paris, France; gService de Chirurgie infantile orthopédique, Hôpital Necker-Enfants Malades, 149 rue de Sèvres 75015, Paris, France

Background: Hereditary Hypophosphatemic Rickets (HHR) is caused by persistently elevated FGF23 resulting in renal phosphate wasting and decreased 25 vitamin D hydroxylation. Treatment with vitamin D analogues (VDA) has been added to phosphate supplements in the late seventies.

Objective and hypotheses: Our objective was to evaluate the outcomes of VDA and phosphate supplements in adult patients with HHR in comparison with patients who did not receive VDA (i.e. non-treated patients).

Method: We performed a retrospective study of patients diagnosed with HHR. Patients were divided in two groups: group 1: 50 patients (mean age 25.2 years) who received VDA and group 2: 58 patients (mean age 41.7 years), 27 received phosphate supplements, 31 never had any treatment.

Results: Group 1 patients were taller than group two patients, had better correction of leg bowing, less leg corrective surgeries and better dental health. VDA treatment was associated with a higher femoral neck T score and lower fracture incidence in adulthood. Complications such as nephrocalcinosis and hyperparathyroidism were similar between groups (Table 1).

Table 1.
Adult outcomesGroup 1 (with VDA)Group 2P
Female height cm/DS153.8/−1.6147.7/−2.70.0039
Male height cm/DS163.4/−1.9153.2/−3.70.0038
Female BMI (kg/m2)23.425.50.3440
Male BMI (kg/m2)24.327.00.4029
Leg bowing35.9%89%<0.0001
Corrective leg surgery28.0%69.0%0.0001
Femoral neck Z score1.8−0.50.0005
Fractures 5.1%58.6%0.0019
Decayed Missing Filled Teeth index3.419.3<0.0001

Conclusion: The current conventional treatment improves height, leg bowing and cortical bone density. Our results in a large cohort of HHR patients confirm that the use of vitamin D analogues is safe and associated with better long-term outcomes. However several features of the disease are not cured and require new therapies.