Objective: To determine the skeletal effects of alendronate therapy in men with primary hyperparathyroidism (PHPT) in comparison with those in postmenopausal women.
Methods: There essentially are no published data on the effects of bisphosphonate therapy in men with PHPT. We previously conducted a double-blind, randomized, single- crossover trial of alendronate, 10 mg daily, in PHPT and reported that alendronate significantly increases bone mineral density (BMD) at 12 months relative to baseline values. That study sample included both women (n = 28) and men (n = 9) and both premenopausal (n = 4) and postmenopausal (n = 24) women. Study subjects were randomly assigned to receive either alendronate or placebo during the first year, and all subjects received alendronate during the second year. Among the men, 3 received alendronate and 6 received placebo during the first year. The current analysis focuses on the skeletal effects of alendronate therapy in the 9 men during their first year of treatment versus the 6 men during their first year while receiving placebo as well as the 24 postmenopausal women during their first year of alendronate therapy. Paired t tests comparing baseline and 12-month data were performed for the 9 treated men and the 6 control subjects; unpaired t tests were used to compare the 9 treated men and the 24 treated women.
Results: Alendronate therapy for 1 year (n = 9) resulted in a 4.8% increase in BMD at the lumbar spine (P = .1) in comparison with the men who received 1 year of placebo (n = 6). Relative to baseline, men receiving alendronate showed a significant 4.4% gain in BMD at the lumbar spine (P = .009) and a 2.95% gain in total hip BMD (P =.027). A 47% decline in serum levels of bone-specific alkaline phosphatase activity was also noted with alendronate therapy (P = .003). Changes in BMD in the male population were similar to previously reported effects of alendronate therapy in postmenopausal women with PHPT.
Conclusion: Alendronate therapy in men with PHPT is associated with improvements in BMD and reductions in bone turnover. These data, similar to the findings in postmenopausal women with PHPT, suggest that aminobisphosphonates may be of value in providing skeletal protection for men with PHPT. Further study is needed to confirm skeletal protection and fracture efficacy in this population.