R.A. Stemme1, Y. Liu2, J. Hong3, Y. Li3, J.Z. Done1, J. Weller1, A.V. Rudin1, L.F. Morris-Wiseman1, D.L. Segev3,4, M. McAdams-DeMarco3,4, A. Mathur1 1Johns Hopkins University School Of Medicine, Department Of Surgery, Baltimore, MD, USA 2Johns Hopkins University School Of Medicine, Department Of Medicine, Division Of Nephrology, Baltimore, MD, USA 3New York University School Of Medicine, Department Of Surgery, New York, NY, USA 4New York University School Of Medicine, Department Of Population Health, New York, NY, USA
Introduction: Hyperparathyroidism (HPT) commonly persists following kidney transplantation (KT) and can result in bone alterations. We sought to assess the association between HPT at 1-year post-transplant 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 prior to KT and 1-year post-KT were abstracted from the medical record. Non-traumatic fractures occurring beyond 1-year after KT were ascertained using ICD-9/ICD-10 codes. Post-KT HPT was defined as PTH ≥ 70 pg/mL at 1-year post-KT. Competing risk models were used to estimate the association between HPT at 1-year post-KT and risk of fracture, with death treated as a competing risk event.
Results: Among 344 KT recipients, 227 (66.0%) had HPT 1-year post-KT. Compared to recipients without HPT, those with HPT had a higher median BMI (28.6 kg/m2 vs. 26.4 kg/m2, p<0.01), longer dialysis vintage prior to KT (4.2 vs 2.7 years, p<0.01), and were more likely to have an elevated PTH level of ≥ 600 pg/mL prior to KT (19.3% vs. 10.2%, p=0.04). There was no difference between groups in rates of osteoporosis at time of KT. Recipients with HPT were more likely to have hypercalcemia (41.0% vs 24.8%) and vitamin D-deficiency (67.6% vs 44.3%) 1-year after KT (all p<0.01). After adjusting for confounders, HPT 1-year after KT was associated with a 3.01-fold increased risk of fractures (95% CI: 1.04-8.71). There was no difference in this association by age, sex, race, or dialysis vintage.
Conclusion: Recipients with HPT 1-year after KT had a significantly higher risk of fractures compared to patients without post-transplant HPT. Identifying risk factors is crucial for informing therapeutic interventions to mitigate fracture-related morbidity and mortality. Future studies should establish standardized practice guidelines for treatment of post-KT HPT, a potentially modifiable risk factor.