MSc student University of Toronto, Toronto, Canada, Canada
Background: Oral bisphosphonates are first-line therapy for osteoporosis; however, some patients do not tolerate these medications or have inadequate treatment response. Raloxifene is a selective estrogen receptor modulator approved as second-line therapy for postmenopausal osteoporosis and was added to the Ontario Drug Benefit (ODB) formulary in 1999. Evidence suggesting a higher risk of thrombosis and stroke with raloxifene began to emerge in 2004.
Objectives: To estimate the number of older females in Ontario initiating raloxifene and describe trends in use over time.
Methods: The ODB program covers prescription drugs listed on the formulary for residents aged 65 or more years. We leveraged pharmacy claims (ODB) data to identify all females residing in the community who initiated raloxifene since 1999 through to December 2022. We restricted inclusion to patients aged 66 or more years to permit a 1-year lookback to define prior osteoporosis drug exposure. The number of patients initiating raloxifene was plotted by calendar year, and patient age and exposure to other osteoporosis medications were summarized using descriptive statistics.
Results: We identified 22,205 eligible females (mean age = 74.2 years, standard deviation = 6.2); 58% with history of oral bisphosphonate exposure. The annual number of patients initiating raloxifene peaked in 2001 at 3879, followed by a decline to 3304 in 2002, and then a gradual decline from 2152 in 2003 to 216 in 2014. The total number of patients who initiated raloxifene since 2015 represents only 4% of our cohort. However, close to 100 females continued to initiate raloxifene each calendar year (mean=115, SD=40), with 90 patients initiating raloxifene in 2022.
Conclusions: Raloxifene prescribing has declined substantially since 2003, yet a small number of older females initiate raloxifene every year. Raloxifene exposure thus remains an important consideration for the treatment of osteoporosis. Better understanding of the safety and benefits of raloxifene therapy is important to inform future prescribing.