The Association Between Post-Kidney Transplant Persistent Hyperparathyroidism and Fracture Risk: A Longitudinal Cohort Study.

INTRODUCTION: Hyperparathyroidism (HPT) commonly persists following kidney transplant (KT) and can result in bone alterations. However, the association between persistent HPT post-KT and fracture risk is not well-understood. We sought to quantify the association between persistent HPT at 1-year post-KT and fracture risk among KT recipients. METHODS: We leveraged a longitudinal prospective cohort of 344 adult KT recipients who underwent KT at a single institution (12/2008-07/2019). PTH levels were retroactively abstracted, and fractures after 1-year-post-KT were ascertained using ICD-9/ICD-10 codes. Competing risk models were used to estimate the association between persistent HPT (PTH ≥ 70 pg/mL) at 1-year post-KT and the risk of fracture, with death treated as a competing event. RESULTS: Among 344 KT recipients, 227 (66.0%) had persistent HPT at 1-year post-KT. After adjusting for confounders, HPT 1-year after KT was associated with a 3.11-fold increased risk of fractures (95% CI: 1.08-8.91). There were no differences in this association by age, sex, race, eGFR at 1-year-post-KT, osteoporosis at KT, or dialysis vintage. CONCLUSION: Recipients with HPT 1-year after KT had a significantly higher risk of fractures than those without persistent HPT. Future studies should establish standardized practice guidelines for the treatment of persistent HPT to mitigate fracture-related morbidity and mortality.