Antithrombotic therapy, vascular events and mortality after non-cardioembolic ischaemic stroke: a nationwide hospital-based cohort study in Japan

BACKGROUND: Limited evidence is available regarding rates of vascular events and mortality associated with an initial and a recurrent ischaemic stroke (IS) in people with non-cardioembolic IS (NCIS). AIMS: This study evaluated rates of clinical events and antithrombotic therapy among people with NCIS or transient ischaemic attack (TIA), and subsequent event rates after a first recurrent IS. METHODS: Adults with a first hospitalisation for NCIS or TIA between 1 January 2015 and 29 October 2022 were identified in a Japanese nationwide hospital database (N=18 719). NCIS was identified based on diagnostic codes. Clinical events were assessed after discharge of the initial and the first recurrent IS hospitalisations. RESULTS: Rates (per 1000 person-years (95% CIs)) of IS, death, haemorrhagic stroke, myocardial infarction or unstable angina, major bleeding, and newly diagnosed atrial fibrillation were 103.5 (100.0 to 107.0), 45.9 (43.8 to 48.1), 10.6 (9.6 to 11.7), 21.7 (20.2 to 23.2), 60.0 (57.4 to 62.5) and 22.9 (21.3 to 24.4), respectively. In the subcohort with a first recurrent IS (N=3081), rates of these events were 199.9 (186.6 to 213.1), 53.3 (46.5 to 60.2), 15.6 (11.9 to 19.4), 39.6 (33.5 to 45.6), 96.5 (87.1 to 105.9) and 52.7 (45.7 to 59.8), respectively, following the recurrent IS. Following the initial hospitalisation, antiplatelet therapy was used in 71.8% of people. However, only 54.2% of people were prescribed any antithrombotic therapy in the 90 days prior to the first recurrent IS, which increased to 77.0% after the event. CONCLUSIONS: The rate of recurrent IS was high in people with NCIS and more effective, tolerable prevention strategies are needed. The high rate of clinical events following a first recurrent IS may underscore the importance of preventing IS recurrence in people with NCIS.