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).
|Adult outcomes||Group 1 (with VDA)||Group 2||P|
|Female height cm/DS||153.8/−1.6||147.7/−2.7||0.0039|
|Male height cm/DS||163.4/−1.9||153.2/−3.7||0.0038|
|Female BMI (kg/m2)||23.4||25.5||0.3440|
|Male BMI (kg/m2)||24.3||27.0||0.4029|
|Corrective leg surgery||28.0%||69.0%||0.0001|
|Femoral neck Z score||1.8||−0.5||0.0005|
|Decayed Missing Filled Teeth index||3.4||19.3||<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.
20 - 22 Sep 2014
European Society for Paediatric Endocrinology