6722 Increase in Femoral Neck BMD After Parathyroidectomy in Patients with Mild Primary Hyperparathyroidism

Abstract Disclosure: F. Abdul Kather: None. G.A. Clines: None. C. Janney: None. D.T. Hughes: None. N.H. Esfandiari: None. S. Saberi: None. Objective: This study aimed to assess changes in bone mineral density (BMD) following parathyroidectomy in patients with mild primary hyperparathyroidism, defined as serum calcium 10.4 mg/dl to 11.2 mg/dl, by comparing distinct patient variables. Hypothesis: Pre-op demographic factors, laboratory values, and BMD significantly influence post-parathyroidectomy BMD. Methods: This retrospective chart review included 93 subjects with primary hyperparathyroidism who underwent parathyroidectomy between 2000-2022 with BMD measurements performed at the same site pre- and post-parathyroidectomy. Exclusion criteria were age <50 years, GFR <30, recurrent primary hyperparathyroidism, chronic oral glucocorticoid use (>1 month), rheumatoid arthritis, suppressed serum TSH, hormone-deprivation therapy, cinacalcet use, and prescription osteoporosis medication therapy. Statistical analyses were performed using ANOVA and a p-value of <0.05 was considered statistically significant. Results: The mean age of the subjects was 63.65 ± 6.58 years, who were mostly female (84.9%) and white (88.2%). Pre-op laboratory values revealed mean uncorrected calcium 10.52 ±0.26 mg/dL, corrected calcium 10.25 ± 0.32 mg/dL, 25-OH vitamin D 35.82 ±15.31 ng/mL, and parathyroid hormone (PTH) 99.12 ±37.06 pg/mL. Pre-op mean bone densities for the lumbar spine, femoral neck, and total hip were 1.04 ± 0.16, 0.81 ± 0.11, and 0.87 ± 0.11 g/cm2, respectively, with corresponding T-scores of -1.13 ± 1.23, -1.60 ± 0.74, and -1.13 ± 0.89. Changes in BMD post-parathyroidectomy were determined by comparing pre-op and post-op DXA scans. No statistically significant differences in DXA were found between ages of 50-55 vs. >55, post-op timing of DXA 1-2 years post parathyroidectomy vs. >2 years post parathyroidectomy, number of parathyroid glands removed, the total weight of resected parathyroid glands, pre-op vitamin D level <30 ng/mL vs. ≥30 ng/mL, or pre-op urinary calcium levels <200 mg/day vs. ≥200 mg/day. Grouping subjects by pre-operative DXA T-scores revealed a statistically significant improvement in femoral neck bone density between osteoporotic and osteopenic subjects (p=0.018) and between osteoporotic and normal bone density subjects (p=0.019). No significant differences were identified in the spine and total hip bone density changes among these groups. Conclusion: In subjects with osteoporosis undergoing parathyroidectomy, a significant improvement in femoral neck bone density was observed, unaffected by pre-op variables of age, timing of DXA post parathyroidectomy, parathyroid gland characteristics, and pre-op vitamin D and urinary calcium levels. These findings underscore the potential for tailored interventions in managing bone health post-parathyroid surgery, emphasizing the need for personalized approaches to optimize outcomes in individuals with mild hyperparathyroidism. Presentation: 6/2/2024