Comparative effectiveness of osteoporosis drugs in preventing secondary nonvertebral fractures in taiwanese women

Context: The evidence for relative effectiveness of osteoporosis drugs in secondary prevention of nonvertebral fractures was unclear and could not be extrapolated to the Asian population. Objective: The objective of the study was to compare the relative effectiveness of different classes of osteoporosis drugs in secondary prevention of nonvertebral fractures in Taiwanese women. Design: This was a retrospective cohort study from 2003 to 2007, with up to 6 years of follow-up. Setting: The study included enrollees in Taiwan National Health Insurance. Patients: Patients older than 50 years, with vertebral/hip fracture and were new to osteoporosis therapy, were recruited. Intervention: Patients were classified into the alendronate, calcitonin, or raloxifene group, according to their exposure after follow-up. Main Outcome Measure: The primary outcome of our study was the risk of incident nonvertebral fracture (hip, humerus, or radius fractures).AmultivariateCoxproportional hazardmodeladjusted for fracture risk factors was used to compare the relative fracture risk among three treatment groups under on-treatment scenarios. Propensity score-matched hazard ratioswereexamined,andinteractions between fracture incidence and patients' compliance were investigated as well. Results: Therewere19 840, 9534,and25 483 patients in the alendronate, raloxifene,andcalcitonin groups, respectively. The fracture rates were highest in calcitonin recipients (4.57 per 100 personyears),followed by raloxifene and alendronate. Results from Cox analyses showed raloxifene (hazard ratio 1.47; 95% confidence interval 1.29-1.67) and calcitonin (hazard ratio 1.51; 95% confidence interval 1.29-1.75) had higher nonvertebral fracture risks as compared with alendronate. The risk differences were more pronounced in compliant patients. Conclusion: We found alendronate users had the lowest secondary nonvertebral fracture risk, as compared with raloxifene and calcitonin users. Consistent results were found in a series of sensitivity analyses.