To evaluate determinants of final height in a Brazilian cohort of patients with X-linked hypophosphatemia (XLH), focusing on age at diagnosis and baseline growth status.
Approach:
Study Design: Retrospective observational cohort study including 41 patients with molecularly confirmed XLH followed at a tertiary referral center in Brazil from 1971 to 2025.
Data Collection: Anthropometric and clinical data were extracted from medical records, with final height analysis restricted to 20 patients treated exclusively with conventional therapy.
Statistical Analysis: Correlations were assessed using Spearman coefficients, and multivariable linear regression was performed to identify independent predictors of final height Z score.
Key Findings:
At diagnosis, the mean height-for-age Z-score was −1.90 ± 1.56, indicating significant baseline growth impairment.
Age at diagnosis was inversely correlated with height-for-age Z-score (r = −0.77; P = 0.02), while no correlation was observed with BMI-for-age Z-score.
Among patients who reached final height, the mean final height Z-score was −2.96 ± 1.15.
Independent predictors of final height included height-for-age Z-score at diagnosis, age at diagnosis, and target height Z-score.
Interpretation:
Final height in XLH is influenced by genetic potential, baseline growth impairment, and timing of diagnosis.
Limitations:
The study is limited to a small cohort of patients treated exclusively with conventional therapy.
Findings may not be generalizable beyond the Brazilian population.
Conclusion:
In summary, this study highlights the critical role of early diagnosis and initial growth status in determining final height outcomes for patients with X-linked hypophosphatemia. The significant correlations identified suggest that timely intervention and monitoring of growth parameters are essential in optimizing growth potential in this patient population. Further research is warranted to explore the broader implications of these findings and to develop targeted strategies for improving outcomes in XLH.
