Abstract Number: Esoc2026a649 the Impact of Covid-19 on Ischaemic Stroke in the First and Second Pandemic Waves: A Uk Multicentre Cohort Study

Abstract Background and aims During the first wave of the COVID-19 pandemic, infection at the onset of an ischaemic stroke was associated with increased severity and poorer outcomes. We aimed to determine whether the impact of COVID-19 on functional outcome differed between the first and second waves of the pandemic in the UK. Methods We retrospectively analysed data from 24 UK stroke centres. Patients admitted with acute ischaemic stroke during the first wave (up to 6th September 2020), and during the second wave (7th September 2020 to 28th May 2021), were included. In each wave, we assessed whether COVID-19 affected the proportion of patients achieving a favourable functional outcome (mRS 0-1). Results Of 2173 patients with ischaemic stroke, 223 had COVID-19 at the time of onset. Whilst COVID-19 was associated with a reduction in favourable outcome in the first wave (9% vs 28%, p0.001), this adverse impact was not seen in the second wave (20% vs 21%, p=0.453). This interaction between COVID-19 status and wave in predicting favourable outcome was significant in a logistic regression (OR 0.26, 95% CI 0.09–0.69, p=0.007). However, COVID-19 was associated with a 13% higher mortality rate in both the first (20% vs 7%) and second (17% vs 4%, p0.001) waves. Conclusions The adverse impact of COVID-19 on functional outcome seen in the first wave virtually disappeared in the second wave. However, COVID-19 increased mortality similarly in both waves, emphasizing the importance of protecting patients at risk of stroke from this infection. Conflict of interest Wenpeng Zhang: nothing to disclose; Craig J Smith has received honoraria from Bayer not related to the work presented here; Christine Roffe: nothing to disclose; Robert Simister: nothing to disclose; David J Werring has received personal fees from Bayer, Alnylam and Portola, not related to the work presented here; Richard J Perry: nothing to disclose.