Beneficial effect of risedronate for preventing recurrent hip fracture in the elderly Japanese women

Summary A 36-month observational study compared the incidence of unaffected side hip fracture in Japanese female osteoporosis patients with a history of hip fracture between 173 patients receiving risedronate and 356 risedronateuntreated controls. New hip fractures were significantly less frequent in the risedronate group, suggesting a preventive effect in high-risk patients. Introduction The purpose of this study was to investigate the preventive effect of risedronate on second hip fracture immediately following a first hip fracture in Japanese female osteoporosis patients with unilateral hip fracture. Methods We conducted a prospective matched cohort study in 184 patients treated with risedronate and 445 patients not receiving risedronate after discharge from hospital. Both groups were followed-up for 36 months, and the incidence of unaffected side hip fracture and the frequency of adverse events were assessed. Results Efficacy could be investigated in 173 patients from the risedronate group and 356 patients from the control group. Hip fracture was detected in 5 and 32 patients, respectively. Kaplan–Meier estimates of the 36-month fracture incidence were 4.3% in the risedronate group and 13.1% in the control group (P=0.010, log-rank test). The hazard ratios (95% confidence intervals) obtained by univariate and multivariate analysis were 0.310 (0.121– 0.796) and 0.218 (0.074–0.639), respectively, indicating a significantly lower incidence of unaffected side hip fracture in the risedronate group. Adverse events occurred in 38 patients (48 events) from the risedronate group and 94 patients (108 events) from the control group, with serious adverse events in 21 patients (26 events) and 78 patients (88 events), respectively. Conclusions No significant differences were observed between the two groups. The incidence of unaffected side hip fracture was significantly lower in the risedronate group. Accordingly, risedronate may have a preventive effect on hip fracture in high-risk Japanese female osteoporosis patients for fracture with a history of unilateral hip fracture.