Switching from active vitamin D and phosphate supplementation to burosumab significantly corrects lower limb malalignment in pediatric X-linked hypophosphatemia
Bibliographic record
Abstract
X-linked hypophosphatemia (XLH) is a rare disorder of renal phosphate wasting and dysregulated active vitamin D metabolism, ultimately presenting as rickets and osteomalacia, among other manifestations. Lower extremity deformity (genu valgum and/or varum) is frequent in this pediatric population. Despite prompt active vitamin D and phosphate supplementation (active D/Pi), many patients require corrective surgery for lower limb malformation. Burosumab has demonstrated improvements in lower limb malalignment in children with XLH in several studies. We expand on those reports by assessing mechanical femoral tibial angle (mFTA) change in patients enrolled in the XLH Disease Monitoring Program (DMP), (NCT03651505) to determine the impact of initiating burosumab treatment after a history of active D/Pi. Included patients had either switched from active D/Pi to burosumab treatment at the discretion of their treating physician or as part of a burosumab clinical trial, or remained on active D/Pi through Year 3 of the DMP. Year 3 radiographs were compared with baseline to assess mFTA change and gauge improvement. Additional multivariate factor analysis examined 24 attributes to determine which had the greatest association with mFTA change. Change in mFTA was assessed for each limb independently. A greater proportion of limbs of patients switching from active D/Pi to burosumab had improved mFTA compared with those remaining on active D/Pi (p < .023). Odds ratios comparing limbs that improved to those that did not showed that switching to burosumab yields a significantly greater chance of improvement than continuing active D/Pi (OR [95% CI]: 4.38 [1.09-17.50]; p = .0469). Factor analysis identified younger age at burosumab initiation (p = .001) and lower baseline height Z-score (p = .006) as being significantly associated with greater change in mFTA Z-score. This study shows that switching to burosumab significantly improves lower limb malalignment in children with XLH over benefits conferred by active D/Pi, with early burosumab initiation providing the greatest benefit.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".