(P-370) Antithrombotic Therapy Prescription Patterns in the Secondary Prevention of Stroke in Patients with Atrial Fibrillation: Findings from a Real-world, Population-based Study

Background: Antithrombotic treatment (ATT) is recommended for the secondary prevention of ischemic stroke (IS) or transient ischemic attack (TIA), preferably with oral anticoagulants (OAC). Relevant differences between physician strategies in the treatment can be found.

Objectives: To assess ATT prescription patterns for secondary prevention of stroke in a large observational cohort.

Methods:

Design: retrospective, population-based cohort study.
Setting: the study was conducted in the region of Valencia, Spain, with a population of 5 million inhabitants. We included all adult patients with AF or flutter hospitalized after an IS or TIA from 2010 to 2015. Data was extracted from the Valencia Health System Integrated Database (VID).
Exposures or interventions: exposure to three different ATT was considered: antiplatelet therapy (APT), OAC, or both (OAC+APT).
Statistical analysis: first, we assign the initial treatment of the patients considering 30 consecutive days of ATT treatment (or 20 overlapping consecutive days for considering treatment with OAC + APT) within 60 days after hospital discharge from IS or TIA. Then, we calculated interruptions and switching among treatments within one year. Switching was defined as 60 consecutive days with other ATT prescriptions (or at least 40 of these 60 days with both drugs prescriptions for considering switching to OAC + APT) and interruption is considered if there are 60 consecutive days with no treatment. Median time to switching was also assessed.

Results: From 2010 to 2015 a total of 8084 patients with AF suffered a IS or TIA. From these, 6521 (81%) were prescribed ATT: APT (32%), OAC (49%), OAC+APT (19%). The interruption of treatments after 1 year of follow-up since the start of the treatments was: 8% OAC, 8% APT and 6% for OAC+APT. Regarding the switching patterns among groups, we found i) from APT patients to: OAC (10%), median time-to-switch (mtts) = 68d; OAC+APT (6%), mtts=100d. ii) From OAC patients to: APT (1%), mtts=105d; OAC+APT (2%), mtts=113d. iii) From OAC + APT patients to: APT (8%), mtts=60d; OAC (44%), mtts=36d. After the first switching, the proportion of patients in the OAC group increased (60%), whilst the proportion of patients on alternative strategies was reduced (29% and 11% with APT and OAC+APT, respectively).

Conclusions: One third of patients after an ischemic stroke or TIA received only APT and a high proportion received OAC+APT. The strategies remain stable in time (switching and interruption was infrequent), except for those who initiated with APT+OAC, who interrupted the APT in half of the cases in a median time of one month.