OBJECTIVES: We examined the patterns of persistence among warfarin and other common chronic medications in patients with atrial fibrillation (AF) and identified predictors of warfarin non-persistence. METHODS: We used a national, managed care claims dataset (January 1, 2005-December 31, 2007) to evaluate patterns of persistence in patients with AF.  We examined those that filled a prescription for warfarin within 3 months following AF hospitalization discharge and had at least 12-month continuous data prior to and following the first fill.  For comparison, we also evaluated patterns of persistence for other selected, chronically-prescribed medications, including branded, generic, once-, twice-, and thrice-daily medications.  Non-persistence was defined as failure to refill the medication within 60 days from the run-out date of the prior prescription. Survival models were used to identify predictors of warfarin non-persistency.  RESULTS: A total of 28,384 patients with AF were identified; 16,036 (56.5%) filled a warfarin prescription shortly following hospitalization for AF.  A total of 53.5% of warfarin users were persistent on warfarin for at least 1 year.  Among non-persistent patients, average time to non-persistence was 122 (SD 83) days from the first warfarin prescription.  Persistence with pioglitazone, sitagliptin, amlodipine, and once- and twice-daily carvedilol were similar to warfarin.  While persistence with twice-daily carvedilol was similar to once-daily carvedilol phosphase (60.1% vs. 61.3%, p=0.680), persistence of thrice-daily captopril was significantly worse than that of once-daily amlodipine (27.7% vs. 51.9%, p<0.001).   Factors significantly associated with time to non-persistence with warfarin included age, gender, residence in the south and west region, ischemic stroke, urinary tract infection, and warfarin out-of-pocket expense. CONCLUSIONS: Persistence with warfarin among patients with AF is consistent with other chronic medications.  Persistence with thrice-daily, but not twice-daily therapy was worse than once-daily medication.   Factors associated with non-persistence can be used to identify patients and target adherence programs.