Over 12 years in the US and 26 years in Ontario, Canada, we found major differences in osteoporosis medications used. In both countries, osteoporosis medication initiation has not returned to pre-2008 levels; however, denosumab use is increasing. Future work should determine whether targeted screening or undertreatment drives these trends.

Concerns about adverse events caused a rapid decline in osteoporosis medication use globally between 2008 and 2012. Trends in use in recent years have not been described. We aimed to describe and compare trends over time in the initiation and overall use of osteoporosis medications among older adults in the US and Ontario, Canada.

We conducted a serial cross-sectional study leveraging two data sources: healthcare administrative data for all older adult residents of Ontario, Canada (ON) and Medicare claims and enrollment data for a 20% random sample of beneficiaries (US). We included community-dwelling older adults aged ≥ 66 years at their first dispensing of an osteoporosis medication between 05/01/1996–12/31/2022 in ON and 01/01/2008–12/31/2020 in the US. We described and compared the number of incident and prevalent users of osteoporosis medications annually.

We identified 771,025 (average age = 75.2 years; 78% female) individuals in ON and 424,995 (average age = 75.3 years; 85% female) in the US initiating osteoporosis medications. In the US, alendronate and denosumab were the most common therapies, while in ON, risedronate and denosumab were most common. New use of osteoporosis medications dropped more between 2008 and 2011 in the US versus ON (58% vs. 29% relative decrease). Initiation of osteoporosis medications did not rebound to pre-2008 levels.

New use of osteoporosis medications remains below pre-2008 levels, and differs between the US and Canada. Future research should aim to understand drivers of decreased use, like changes in the screening strategy used for initial treatment or persisting concerns about adverse effects.