LAUSR

Introduction: Many national initiatives have focused on increasing public awareness of acute ischemic stroke (AIS) symptoms because earlier treatment is associated with improved outcomes. Our purpose was to evaluate the 10-year trends in the last known well to arrival (LKWA) time in AIS patients and assess disparities. Methods: A retrospective study of consecutive AIS patients admitted to a large integrated healthcare system was performed over a 10-year period from 2014-2023. LKWA time was categorized according to treatment eligibility as 0-4.5, >4.5-24, and >24 hours. Demographic and clinical characteristics, treatment utilization, and modified Rankin Score (mRS) at discharge were extracted from the electronic health records. Trend, bivariate, and multivariable logistic regression analyses were conducted. Results: A total of 11,563 AIS patients were included with 53% (6,163) in LKWA0-4.5, 34% (3,988) in LKWA>4.5-24, and 12% (1,412) in LKWA>24 groups. From 2014-2023, there was a downward trend in the early LKWA0-4.5 from 61% to 46% ( Figure 1, Table 1 ). Concurrently, there was an upward trend in the later LKWA>4.5-24 (31% to 42%) and LKWA>24 (8% to 11%) groups. Table 2 describes the study cohort characteristics. Compared to LKWA0-4.5, the LKWA>4.5-24 group was less likely to receive endovascular thrombectomy (EVT) and more likely to have worse outcomes (mRS2-5). The AIS patients in the LKWA>4.5 groups were more likely to be older >80 years (Odds Ratio=1.18 [95% Confidence Intervals:1.03-1.32]), males (1.10 [1.03-1.17]), Black (1.20 [1.08-1.33]), Asian (1.20 [1.04-1.39]), Medicaid insurance (1.16 [1.06-1.27]), lower income <$80,000 (1.43 [1.24-1.66]), and comorbidities of diabetes (1.29 [1.18-1.41]), hypertension (1.15 [1.05-1.25]), and current smoker (1.31 [1.12-1.52]). Conclusion: In the past decade, there was a downward trend in AIS patients in the early LKWA0-4.5 group with a concurrent upward trend in the later LKWA>4.5-24 group. During the peak of the COVID pandemic (2020), these trends were further exaggerated and did not return to pre-pandemic levels in 2021-2023. The LKWA>4.5 groups were more likely to be older, males, Black or Asian race, Medicaid insurance, lower income, and more comorbidities. Furthermore, the LKWA>4.5-24 group was less likely to receive EVT and more likely to have worse outcomes. These findings highlight the need of implementing targeted efforts towards the late LKWA groups to improve disparities in stroke treatment and outcomes.