Alendronate increases bone mineral density in patients with symptomatic primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is often associated with low bone mineral density (BMD). An open-labeled, prospective trial was conducted to determine whether alendronate (ALN), 10 mg daily, maintains or improves BMD in patients with advanced PHPT. All patients had symptomatic PHPT and met surgical guidelines however refused surgery. Nineteen patients was treated with alendronate for 2 years. The primary outcome index, BMD, was measured at the lumbar spine (LS) and femoral neck (FN) every 6 months by dual-energy x-ray absorptiometry. Serum calcium, phosphorous and PTH, and urinary calcium excretion were monitored every 3 months. Treatment with alendronate over 2 years was associated with a significant (5.3+/-0.4%; p<0.01) increase in LS BMD in comparison with baseline. FN BMD increased significantly at 24 months with alendronate by 2.5%+/-0.7 (p<0.01) from baseline. Serum calcium, phosphorus and PTH, and urine calcium excretion did not change with alendronate therapy. In PHPT, alendronate significantly increases BMD at the LS and FN at 24 months from baseline values with stable serum calcium and PTH levels. Alendronate may be a useful alternative to parathyroidectomy in symptomatic PHPT among those with low BMD, who are candidates for surgery but either decline or for whom surgery is contraindicated.