Sustained efficacy of risedronate in men with primary and secondary osteoporosis: results of a 2-year study

The aim of this study was to assess the effect of treatment with risedronate 5 mg daily relative to control in men with primary or secondary osteoporosis over 2 years. Osteoporosis is a common condition in men that can have serious clinical consequences. In an earlier interim report, we found that 1 year of risedronate therapy resulted in significant increases in bone mineral density (BMD) and a significant reduction in vertebral fractures compared to control in men with osteoporosis. We conducted an open-label, prospective, match-control trial on men with primary or secondary osteoporosis in a single center, outpatient setting. Men with primary or secondary osteoporosis, as defined by a baseline lumbar spine BMD T-score a parts per thousand currency sign -2.5 and a baseline femoral neck BMD T-score a parts per thousand currency sign 2.0, were eligible for this study. Patients who had been treated with bisphosphonates or fluoride within the last 12 months were excluded. A total of 316 men were randomized to risedronate (n = 158) or control (n = 158). Patients were stratified by the presence of prevalent vertebral fractures at baseline and case by case allocated to either daily treatment with risedronate 5 mg daily plus calcium (1,000 mg) and vitamin D (800 IU) or to a control group (daily alfacalcidol (1 mu g) plus calcium (500 mg) for those with prevalent vertebral fractures; daily vitamin D (800 IU) plus calcium (1,200 mg) for those without previous vertebral fractures). Primary study end points were identified prior to study initiation as the incidence of new vertebral fractures and changes in BMD at the lumbar spine, femoral neck, and total hip. Other end points included incidence of nonvertebral fractures and change in body height and back pain. Compared to control, the incidence of new vertebral fractures was significantly reduced in the risedronate 5 mg daily group at 2 years [14/152 (9.2%) for risedronate vs. 35/148 (23.6%) for control (61% risk reduction; P = 0.0026)]. Treatment with risedronate 5 mg daily also resulted in significant improvements in BMD at 2 years at all three skeletal sites (lumbar spine, 6.5 vs. 2.2%; femoral neck, 3.2 vs. 0.6%; total hip, 4.4 vs. 0.4% (P < 0.001 for all treatment comparisons). Significant reductions in the incidence of nonvertebral fractures (11.8 vs. 22.3%; P = 0.032), average loss in height, and back pain were also observed in risedronate-treated patients relative to control. In this 2-year study, daily 5 mg risedronate significantly reduced the risk of vertebral and nonvertebral fractures, improved BMD, decreased height loss, and reduced back pain in men with osteoporosis. Efficacy was sustained over 2 years; a consistent 60-61% risk reduction in vertebral fractures was observed at 1 and 2 years, respectively. These data demonstrate that daily risedronate is effective long-term therapy for men with primary or secondary osteoporosis.