Exposure
Treatment with an OAC was checked against the prescription fulfillment dates and the number of days of medication supplied for each fill. Exposure to treatment was considered in all analyses. We consider that a gap of less than 30 days between the end of a treatment period and a new fill corresponded to continuous treatment. Patients were censored when they discontinued a treatment or switched to another OAC or to another dose level. Allowing a gap in treatment of up to 30 days is reasonable because of the DOACs’ short half-life. Taking account of this definition, the adherence rate over the 12-month assessment period was at least 92% for all included patients. The patient’s OAC exposure and censored status were updated every 30 days.