Discontinuation and reinitiation patterns of osteoporosis treatment among commercially insured postmenopausal women

Objective: Poor adherence to chronic medications is common and compromises medication effectiveness. We sought to describe longitudinal patterns of osteoporosis medication use. Study design: This was a retrospective observational cohort study using 2005-2009 data from a large, commercially insured population. Methods: Patients were women aged >= 55 years initiating osteoporosis therapy who had a >= 12-month (baseline) period with no osteoporosis therapy claims preceding initiation, and >= 24 months follow-up after therapy initiation. Discontinuation was defined as a gap > 60 days (varied in sensitivity analyses) in prescription claims. Reinitiation was defined as a prescription claim for the same or different osteoporosis therapy following the therapy gap. Discontinuation and reinitiation patterns were described using Kaplan-Meier analysis. Multivariable Cox regression assessed the impact of baseline factors on reinitiation. Results: Of the 92,839 patients, 45%, 58%, and 70% discontinued therapy at 6, 12, and 24 months, respectively, following initiation. Of the discontinuers, 46% reinitiated therapy, with the majority doing so within 6 months of discontinuation. Women were less likely to reinitiate therapy if they were older (P < 0.0001) or were hospitalized during baseline (P = 0.0007). Women who discontinued treatment early (< 6 months) following initiation were less likely to reinitiate (P < 0.0001) and remained on therapy for shorter periods following reinitiation. Depending on the available observation time, the median time on therapy following reinitiation was 58-193 days. Study findings did not change appreciably in sensitivity analyses. Conclusion: Many patients stop and restart treatment for osteoporosis. A better understanding of determinants of treatment stopping and restarting could inform adherence improvement efforts.