Long-term persistence and switching patterns among women using osteoporosis therapies: 24-and 36-month results from POSSIBLE US™

Persistence with postmenopausal osteoporosis (PMO) medications is not well characterized beyond 12 months. Of 3,011 postmenopausal women treated in primary care, 36.8 % continued baseline PMO medication during 36 months of follow-up. Many factors were associated with nonpersistence, including newly initiating or switching therapy, and reporting moderate to severe side effects. Persistence with postmenopausal osteoporosis (PMO) medications is not well characterized beyond 12 months. We describe 24- and 36-month persistence using patient-reported data from women with different PMO treatment histories in the US primary care setting. Data from 3,011 participants of the Prospective Observational Scientific Study Investigating Bone Loss Experience (POSSIBLE US (TM), 10/2005-12/2008) and Kaplan-Meier methods were used to estimate the probability of persisting (i.e., not discontinuing or switching PMO agents) with baseline PMO medication and hazard ratios for predictors of nonpersistence 24 and 36 months after study entry. The probability of persisting with the baseline medication was 46.2 % (95 % confidence interval [CI] 44.2-48.1 %) during 24 months of follow-up and 36.8 % (95 % CI 34.7-38.9 %) during 36 months of follow-up. In adjusted analyses, newly initiating therapy or switching to a new agent, reporting moderate to severe side effects, having lower disease-specific quality of life scores, smoking, and residing in the South or West USA (all measured at study entry) were independent predictors of nonpersistence in both time periods. The majority of participants who discontinued therapy and had the opportunity to reinitiate (i.e., discontinued a parts per thousand yen4 months before the end of follow-up) restarted therapy (24 months 69 %; 36 months 75 %). In this primary care cohort, a minority of women continued their baseline PMO therapy during a 24- to 36-month follow-up. Supporting patients during the initiation of a new therapy or if side effects occur may improve persistence and increase the therapeutic benefit of PMO medications.