Short- and long-term changes in bone mineral density of the lumbar spine after parathyroidectomy in patients with primary hyperparathyroidism

The aims of this study were (1) to analyze whether correlations exist between lumbar spine (LS) bone mineral density (BMD) and the main preoperative biochemical parameters in a large population of patients with primary hyperparathyroidism (HPT); and (2) to evaluate the LS-BMD changes after parathyroidectomy (PTx) at long-term follow-up. Sixty-two patients (median age 57 years, range 23-82 years) with confirmed primary HPT underwent LS osteodensitometry by dual-energy X-ray absorptiometry with BMD measurements at the L2-L4 region before surgery and at I year and 2 years after successful PTx. Three groups of patients were considered: Group A (men, n = 14, 22.6%), Group B (premenopausal women, n = 12, 19.3%), and Group C (postmenopausal women, n = 36, 58.1%). There were no linear correlations (P - NS) among the main biochemical parameters, the age of the patients, and their baseline LS-BMD values that were significantly (P < 0.01) lower in Group C patients. At 2-year follow-up the LS-BMD improved by 13.0%, 11.5%, and 11.7% in Groups A, B, and C, respectively (P - NS). In order to compare groups with the same linear relationship between age and LS-BMD, a subgroup of postmenopausal patients aged less than or equal to 60 years (Group C2) was considered. ANOVA showed that the improvement of the LS-BMD at 1- and 2-year follow-up was higher (P - 0.002) in Group B than in Group C2 patients. The result was confirmed by using the Mann-Whitney U-test (P = 0.0078). Improvement of LS-BMD after successful PTx was significantly (P < 0.01) higher in premenopausal women, suggesting a possible role of estrogen hormone in complete bone remodeling.