MON-773 The Comparison Study of Bone Mineral Density(BMD) between Pateints with Normocalcemic and Hypercalcemic Hyperparathyroidism after Kidney Transplantation and its Predictors

Abstract Disclosure: G. Saksirisampant: None. Introduction: Persistent hyperparathyroidism is a well-established complication following kidney transplantation with a significant impact on bone health. This condition can lead to bone thinning and an elevated risk of fractures. However, a comparison between normocalcemic and hypercalcemic hyperparathyroidism is less well-studied. Objective: This study aims to compare bone mineral density (BMD) values among post-kidney transplant patients with normocalcemic hyperparathyroidism and hypercalcemic hyperparathyroidism. The secondary objective is to explore clinical factors that predict BMD values and BMD changes over time in this population. Method: This cross-sectional study included patients who were more than 1 year post-kidney transplant and had persistent hyperparathyroidism documented more than 2 times. Medical history, laboratory results and BMD values were collected. Results: This study included a total of 130 patients, 64 (49.2%) had normocalcemic hyperparathyroidism and 66 (50.8%) had hypercalcemic hyperparathyroidism. 53 patients underwent BMD measurement. There were no different in baseline characteristic between BMD measurement and non-BMD measurement group (excluding BMI and parental hip fracture). Patients in the hypercalcemic hyperparathyroidism group had higher iPTH levels (127.1 vs 84.6 pg/mL, P <0.001) and corrected calcium levels (10.7 vs 9.6 mg/dL, P < 0.001) when compared to those in the normocalcemic group. Mean BMD values (g/cm²) in the hypercalcemic vs normocalcemic groups at all sites were similar. Corrected calcium levels showed a non-significant trend to a negative association with BMD change (n = 17) at the femoral neck (β -0.026, P = 0.097) and a significant negative association with BMD change at the 1/3 radius (β -0.033, P = 0.033). Conclusion: Among persistent hyperparathyroidism after kidney transplant patients, BMD results of hypercalcemic and normocalcemic hyperparathyroidism were similar. High corrected calcium levels associated with more bone loss in cortical-dominated bone, particularly in the 1/3 radius. Presentation: Monday, July 14, 2025