Successful Transition in Rare Metabolic Bone Diseases: One-Year Outcomes of a Multidisciplinary Pediatric-Adult...

Background and Objectives: Pediatric-onset metabolic bone diseases, including osteogenesis imperfecta (OI), hypophosphatemic rickets (XLH), hypoparathyroidism, and McCune-Albright syndrome (MAS), require lifelong follow-up because of persistent skeletal fragility, biochemical abnormalities, and functional morbidity extending into adulthood. However, evidence regarding structured transition from pediatric to adult care in these rare disorders remains limited. This study evaluated one-year outcomes of a multidisciplinary transition program for adolescents and young adults with rare metabolic bone diseases. Materials and Methods: This retrospective cohort study included 20 patients aged ≥17 years who underwent evaluation through a structured transition pathway consisting of multidisciplinary team meetings, a joint pediatric-adult transition clinic, and subsequent follow-up in adult endocrinology. Demographic, clinical, treatment, and transition-related data were extracted from medical records. The primary outcome was successful transition, defined as at least one adult endocrinology visit within 12 months. Secondary outcomes included attendance at the transition clinic, follow-up continuity, and treatment modifications. Results: All patients underwent multidisciplinary evaluation, and 85% attended the joint transition clinic. Successful transfer to adult endocrinology was achieved in 90% (18/20), while regular follow-up during the first year was maintained in 75%. Retention was highest in patients with OI, MAS, XLH, vitamin D-dependent rickets, and DiGeorge syndrome (100%). Greater variability was observed in postoperative and primary hypoparathyroidism. Treatment adjustments were required in 40% of patients, including optimization of phosphate/calcitriol replacement and reassessment of bisphosphonate or burosumab therapy. Three patients were lost to follow-up. No acute transition-related complications were observed. Conclusions: In this small exploratory cohort, implementation of a structured multidisciplinary transition pathway was feasible and was accompanied by high transfer and one-year retention rates. Observed differences across diagnostic subgroups should be interpreted cautiously, and larger multicenter comparative studies are needed to evaluate the effectiveness of structured transition frameworks.