Adult Height Improved Over Decades in Patients with X-Linked Hypophosphatemia: a cohort study.

OBJECTIVES: The aim of this study is to analyze height after cessation of growth (final height FH) and its evolution over the last decades in X-linked hypophosphatemia (XLH) patients in France, as data on natural history of final height in XLH is lacking.

DESIGN: We performed a retrospective observational study in a large cohort of French XLH patients with available data on final height measurements.

MATERIALS AND METHODS: We divided patients into 3 groups according to their birth year: group 1 born between 1950 and 1974, group 2 between 1975 and 2000 and group 3 between 2001 and 2006 respectively and compared their final heights.

RESULTS: 398 patients were included. Mean final heights were the following: for group 1 -2.31±1.11 SDS (n=127), 156.3±9.7cm in men and 148.6±6.5 cm in women, for group 2 -1.63±1.13 SDS (n=193), 161.6±8.5 cm in men and 153.1±7.2 cm in women and for group 3 -1.34±0.87 SDS (n=78), 165.1±5.5 cm in men and 154.7±6 cm in women. We report a significant increase in mean FH SDS over three generations of patients, for both men and women (p<0.001). FH SDS in male (-2.08 ±1.18) was lower than in female (-1.70 ±1.12), p=0.002.

CONCLUSION: Final height of XLH patients in France increased significantly over the last decades. Even though men's final heights improved more than women's, men with XLH remain shorter reflecting a more severe disease phenotype. While the results are promising, most patients with XLH remain short leaving room for improvement.