Background/Aim: 25 to 40% of children with well-controlled X-linked hypophosphatemia (XLH) show linear growth failure, despite optimal conventional treatment (oral phosphate supplementation and active forms of vitamin D) with final height -2 SDS. Recombinant human growth hormone (rhGH) may be an adjuvant treatment of the growth retardation in these patients. Therefore, the main objective of this study was to describe how rhGH treatment improves final height in children with XLH.
Materials/Methods: In our retrospective observational study we included children with XLH who received rhGH for at least one year and reached their final height. Final height was defined as age >16 years, or bone age > 16 years, or growth velocity <2 cm/year. We collected weight, height, and body mass index (BMI) at birth⟶at XLH diagnosis⟶at start of rhGH treatment⟶2 two years after rhGH treatment⟶at the end of rhGH treatment⟶at the last visit.
Results: 34 patients (13 male / 21 female) were included. Mean age at start of rhGH treatment was 9.8±3.5 years. Duration of rhGH treatment and follow up were 3.4±2.9 and 4.5±3.1 years, respectively. The last visit was performed at 19.2±3.4 years. Mean doses of rhGH at initiation and the end of treatment were 77.4±14.5 and 66.8±20.5 µg/kg/day, respectively. The average height of patients significantly increased from -2.4±0.9 SDS at initiation, to -1.5±0.7 SDS (P<0.001) after 2 years of rhGH treatment, to -1.2±0.9 SDS (P=0.67) at rhGH discontinuation and to -1.3±0.9 SDS at final height. The global height increment of rhGH was 1.2±0.7 SDS.
Conclusion: Treatment with rhGH significantly increases final height SDS in comparison to pre-treatment height. Most height gain is obtained during the first 2 years of treatment and is sustained through final height despite treatment interruption.
|Diagnosis of XLH||Before rhGH||2 years after rhGH||End rhGH||Last visit|
19 - 21 Sep 2019
European Society for Paediatric Endocrinology