Objective To investigate the efficacy of minodronate in the treatment of glucocorticoid-induced osteoporosis (GIO). Methods The study population included patients in whom the administration of minodronate (50 mg, once every 4 weeks) had been newly started for the treatment of GIO in Niigata Rheumatic Center from 2012 to 2015. Patients who were bisphosphonate-naïve and those who switched from other bisphosphonates were classified into the naïve and switch groups, respectively. The changes in the bone mineral density (BMD) and bone metabolic markers after one year of minodronate treatment were retrospectively evaluated. We also compared the BMD and bone turnover marker changes of minodronate-naïve patients with those in whom alendronate or risedronate had been prescribed as a first bisphosphonate (control group). Results Minodronate was prescribed to 142 patients, and data were successfully obtained from 120 patients. New vertebral fractures were observed in 5 of the 142 patients; 1 fracture occurred during the cessation of minodronate for dental treatment, and 3 patients already had multiple vertebral fractures before the initiation of minodronate. The patients' tartrate-resistant acid phosphatase 5b (TRACP-5b) (-27.0%, p<0.001) and bone alkaline phosphatase (BAP) (-15.7%, p<0.01) levels were decreased, but no patients showed a decrease to below the normal range. One year of treatment with minodronate significantly increased the lumbar BMD in the naïve (+3.9%, p<0.001) and switch (+2.3%, p<0.001) groups. Although the femoral BMD did not change to a significant extent overall, the patients with a low young adult mean (YAM) (<80%) at baseline showed a significant increase in their femoral BMD (+2.1%, p=0.034) values. Compared with the control group, the minodronate-naïve group showed a significant decrease in the TRACP-5b levels and a significant increase in the lumbar BMD. Conclusion The administration of minodronate appears to be an effective treatment for GIO.
Keywords: bisphosphonate; bone mineral density; bone turnover marker; glucocorticoid-induced osteoporosis; minodronate; minodronic acid.