Short- and long-term changes in bone mineral density following parathyroidectomy in male and female patients with primary hyperparathyroidism

Background: In primary hyperparathyroidism (PHPT) the skeletal involvement is characterized by the loss of the cortical bone and consequently reducing bone mineral density (BMD), and parathyroidectomy (PTx) may lead to normalization of bone remodeling. The aim of this study was to correlate the results of PTx in male patients, and in pre- and postmenopausal women with PHPT. Patients and methods: Sixty-two patients (median age 57 years, range 23-82 years) with PHPT underwent osteodensitometry using a dual-energy X-ray absorptiometry with BMD measurement at the L2-L4 region: (1) 2-5 weeks before surgery, (2) 12-15 months, and (3) 23-26 months after successful PTx. There were 14 (22.6%) men aged 56.5812.66 years (Goup A), 12 (19.4%) premenopausal women aged 42.5+/-8.22 years (Group B), and 36 (58.0%) postmenopausal women aged 63.03+/-7.54 years. A significant (p=0.00, Student’s t-test) difference in age between Group B and C was found. Main baseline serum biochemical data were the following (Groups A, B, C): calcium 2.946+/-0.26, 2.971+/-0.27, 2.938+/-0.26 mmol/L, p=NS; bone alkaline phosphatase: 61.71+/-22.21, 61.75+/-33.36, 97.31+/-73.74 U/L, p=NS; creatinine: 79.64+/-14.67, 69.25+/-17.52, 82.0+/-24.26 micromol/L, p=NS; PTH: +/-64.64+/-87.55, 192.67+/-133.25, 175.19+/-132.06 ng/L, p<0.05 between male and female patients. Results: None of the Group C patients received estrogen replacement therapy at any time, and no Group B patient used oral contraceptives. Preoperative BMD (g/cm2) values were (Groups A, B, C): 0.867+/-0.134, 0.853+/-0.061, 0.749+/-0.143; p<0.05 between Group A and C. Postoperative values were: (1) 12-15 months after PTx: 0.942+/-0.212 (+8.65%), 0.921+/-0.048 (+7.97%), 0.835+/-0.152 (+11.48%), and (2) 23-26 months after PTx: 0.987+/-0.215 (+4.77%), 0.948+/-0.075 (+2.93), 0.863+/-0.152 (+3.35%), respectively. A significant (p<0.05) difference was found between baseline and one-year BMD only in Group B patients. Conclusions: In patients with PHPT, at long-term follow-up, BMD of the lumbar spine significantly improves after PTx in premenopausal women, suggesting a higher bone sensitivity to serum PTH normalization.