Systematic Review: Efficacy of Medical Therapy on Outcomes Important to Pediatric Patients With X-Linked Hypophosphatemia

OBJECTIVE: To examine the evidence addressing the management of X-linked hypophosphatemia (XLH) in children to inform treatment recommendations. METHODS: We searched Embase, MEDLINE, Web of Science, and Cochrane Central up to May 2023. Eligible studies included randomized controlled trials (RCTs) and observational studies of individuals younger than 18 years with clinically or genetically confirmed XLH. Manuscripts comparing burosumab to either no treatment or conventional therapy (phosphate and active vitamin D) or evaluating conventional therapy to no treatment were included. Two reviewers independently determined eligibility, extracted data, and assessed risk of bias (RoB). GRADE methodology was used to assess evidence certainty. RESULTS: We screened 4114 records and assessed 254 full texts. One RCT and one post hoc study proved eligible when comparing burosumab to conventional therapy or no treatment. The open-label RCT was at high RoB, with certainty of evidence ranging from moderate to very low. Burosumab, compared to conventional therapy, probably prevents lower limb deformity and improves physical health quality of life (QoL) (moderate certainty). Burosumab may increase height and enhance the burden of symptoms related to chronic hypophosphatemia (low certainty). Burosumab probably increases treatment-emergent adverse events (moderate certainty) and may increase dental abscesses (low certainty). One observational study assessing conventional therapy vs no treatment was at high RoB, providing very low certainty evidence regarding the impact of conventional therapy on final height. CONCLUSION: Our review indicates that burosumab likely provides benefits to children by preventing lower limb deformity and improving physical health QoL while potentially increasing height. However, burosumab may also increase adverse events. Our review found limited evidence regarding the impact of conventional therapy compared to no treatment on final height. Further research is required to understand the long-term effect of medical therapy in children.