BACKGROUND:Many national initiatives focus on promoting early hospital arrival of patients with acute ischemic stroke (AIS) because treatment effectiveness is time-dependent. However, several studies reported time-delays in hospital arrival, especially during the COVID-19 pandemic. Our purpose was to evaluate the 10-year trends in last known well to arrival (LKWA) time and assess disparities in patients with AIS. METHODS:A retrospective study of consecutive patients with AIS in the United States admitted to a large, socioeconomically diverse health care system in the New York metropolitan area was performed from 2014 to 2023. LKWA time groups were categorized according to treatment eligibility: 0 to 4.5, >4.5 to 24, and >24 hours. Demographic and clinical characteristics, treatment utilization, and modified Rankin Scale at discharge were extracted from electronic health records. Trend, bivariable, and multivariable logistic regression analyses were conducted. RESULTS:A total of 11 563 patients with AIS were included with 53% (6163) LKWA 0 to 4.5, 34% (3988) LKWA >4.5 to 24, and 12% (1412) LKWA >24 groups. From 2014 to 2023, there was a significant downtrend in the early LKWA 0 to 4.5 (61%-46%) with uptrends in the later LKWA >4.5 to 24 (31%-43%) and LKWA >24 (8%-11%) groups (P<0.001). In the LKWA >4.5 groups, the gap widened between racial categories after COVID (2021-2023; P=0.004). Compared with LKWA 0 to 4.5, the LKWA >4.5 to 24 group was less likely to receive endovascular thrombectomy (P<0.001) and more likely to have worse outcomes (modified Rankin Scale, 2-5; P<0.001). LKWA >4.5 groups were more likely to be older >80 years of age (odds ratio, 1.33 [95% CIs, 1.11-1.58]), men (1.11 [1.03-1.20]), Black patients (1.21 [1.09-1.34]), Asian patients (1.20 [1.03-1.39]), Medicaid insurance (1.18 [1.08-1.29]), and low-income <$80 000 (1.39 [1.20-1.61]). CONCLUSIONS:In the past decade, there was a significant uptrend in patients with AIS arriving in the late LKWA >4.5 groups. Socioeconomic disparities were observed with a persistent uptrend in non-White patients in the late LKWA >4.5 groups after the COVID pandemic. These findings highlight the need to implement targeted efforts to improve disparities in LKWA time in patients with AIS.