(B-132) Raloxifene Use Over Time Among U.S. Medicare Beneficiaries

Background: Osteoporosis (OP) is a condition that occurs when bone is reabsorbed more quickly than it is regenerated. Raloxifene may be prescribed as a second-line OP treatment due to failure in response or intolerance to first-line medications; however, given concerns about cardiovascular events and newer OP therapies, modern trends in raloxifene utilization in the US are unknown.

Objectives: To describe trends in raloxifene use over time in the US, and measure persistence to raloxifene among older adult US Medicare beneficiaries.

Methods: We conducted a cohort study using US Medicare enrollment and claims data. The source population included a 20% random sample of female US Medicare FFS beneficiaries who initiated raloxifene between 2008 and 2020, were residing in the community, and were aged >65 years. The study exposure was raloxifene use identified in Medicare Part D claims. We measured the number of incident users each year (first-ever raloxifene dispensation) and prevalent use each year (all patients with use in a given year). The study outcome was persistence of raloxifene prescription use at time t. Persistence was defined as raloxifene continuation without a gap greater than 90 days. Patients were followed from the first raloxifene dispensation until discontinuation, death, or study end date. Kaplan-Meier estimators assessed persistence at 6- and 12-month intervals.

Results: We identified 25,570 eligible females initiating raloxifene. The mean age was 74.5 (SD=6.65) years. Of these, 74.7% were non-Hispanic White, 10.2% were Asian/Pacific Islander, 7.9% were Hispanic, 3.4% were Black/African American, and 3.7% were ‘other’ or ‘unknown’ race. In 2008, we identified 4,437 incident users, which decreased over time to n=1,614 in 2015 to n=957 incident users in 2020. However, prevalent use remained relatively steady over the study period (n=5,611 in 2009, n=6,471 in 2015, and n= 5,391 in 2020). Among female beneficiaries initiating raloxifene, at 6 months, 64% persisted with therapy. Persistence at 1, 2, 3, and 5 years was 47%, 31%, 22%, and 12%, respectively.

Conclusions: Although the number of new users of raloxifene has decreased greatly over time, overall use of raloxifene each year has remained steady, and persistence to raloxifene is higher than to many other OP medications. Raloxifene may be an important therapy for certain groups of patients with OP in the US, especially those at risk of breast cancer.