Changing patterns of use of osteoporosis medications in the years after launch: implications for comparative effectiveness research.

PURPOSE: Newly marketed medications may be used selectively in patients with more severe disease. Changes in patterns of use following a drug's introduction to the market can greatly influence results from non-experimental comparative effectiveness research. We sought to explore this issue by characterizing trends in oral and injectable prescription drug claims for the prevention and treatment of osteoporosis.
METHODS: We examined a post-menopausal population of women age 55 years and older in the Truven Health Analytics MarketScan® Databases. We used propensity score (PS) methods to describe how predictors of new users of oral and injectable osteoporosis medications change over time.
RESULTS: We found that injectable osteoporosis medications tended to be used more selectively in the higher risk patients shortly after launch. Over time, they appeared to be used increasingly in lower risk patients.
CONCLUSION: If disease severity is incompletely captured in the data, comparative effectiveness of novel osteoporosis medications may be difficult to accurately estimate, particularly when medications are new to market.