OBJECTIVES: Persistence to orally and/or frequently administered osteoporosis treatments is poor. Indeed, previous retrospective research has shown that approximately 50% of patients discontinue oral treatments within one year. Denosumab is administrated as a treatment for postmenopausal osteoporosis (PMO) via a subcutaneous injection once every 6 months, and better persistence with denosumab has been shown in randomized trials. The current study estimated treatment persistence among women initiating denosumab for PMO in Sweden. METHODS: The study included post-menopausal women who initiated denosumab between May 2010 and July 2012 in the Swedish National Prescription Register. One injection of denosumab was defined as 6 months of persistence. Patients were considered persistent for an additional 6 months if they filled their next denosumab prescription within 6 months + 56 days (permissible gap). Subgroup analyses included comparisons of pre-treated vs. treatment-naïve patients to other osteoporosis treatments, and of patients initiating denosumab treatment in 2010/2011 vs. 2012. RESULTS: The study identified 2,315 incident users of denosumab. Mean (SD) age was 73.7 (9.0) years and 60.7% were pre-treated. 83% (CI95:81-84) of patients were persistent at 12 months, 69% (CI95:67-71) at 18 months and 62% (CI95:60-65) at 24 months. Increasing the permissible gap to 90 or 180 days resulted in 12-month-persistence of 85% and 91%, respectively. Pre-treated patients were more persistent than treatment-naïve patients after 18 (71% vs. 67%) and 24 months (65% vs. 58%), but not at 12 months. No difference was observed between patients starting their treatment during 2010/2011 and 2012. CONCLUSIONS: Among Swedish women with PMO, persistence to denosumab treatment is high, and pre-treated patients are more persistent than treatment-naïve patients. Given the poor persistence to oral osteoporosis treatments, denosumab treatment could, in these patients, be considered a relevant alternative to increases persistence and hence optimizes outcomes in PMO.