Zoledronic acid treatment of osteoporosis: effects in men

To study changes in bone mineral density (BMD) and a bone resorption marker in elderly men who received off-label zoledronic acid for osteoporosis treatment.

We conducted a retrospective review of medical records of 50 male veterans who had received at least one 4-mg intravenous infusion of zoledronic acid and had BMD measurements at 2 of 3 skeletal sites both before the infusion and at a mean of 2.2 years after the infusion. Patients were classified into those who had never received bisphosphonate therapy versus those who had previously received such treatment.

In our study population, 66% of patients had been prescribed orally administered bisphosphonates or intravenously administered pamidronate before receiving zoledronic acid. Larger increases in spine BMD (6.7% versus 3.4% [P<.05]; per year: 2.8% versus 1.2% [P<.01]) and total hip BMD (3.2% versus 0.1% [P<.03]; per year: 1.3% versus 0.02% [P<.02]) occurred after infusion of zoledronic acid in bisphosphonate-naïve patients in comparison with those who had previous bisphosphonate exposure. In addition, 26 of 50 patients (52%) had suppressed urinary N-terminal telopeptide of cross-linked collagen type I (NTx) (a bone turnover marker) at 12 months, and 5 men had NTx suppression for 24 months after infusion.

Our data suggest that 4 mg of intravenously administered zoledronic acid is an effective treatment for increasing BMD in a "real-world" population of men with osteoporosis. The prolonged suppression of urinary NTx after zoledronic acid infusion raises the question of whether this treatment could be given less frequently than every year. The changes seen in BMD during a mean period of 2 years were similar to those reported in clinical studies with alendronate therapy in men and zoledronic acid treatment in women.