Temporal trends and resource utilization of inter-hospital transfers in acute ischemic stroke: a nationwide retrospective cohort study

This study investigates temporal trends and resource utilization associated with inter-hospital transfers (IHT) among patients with acute ischemic stroke (AIS). In this retrospective cohort study, the National Inpatient Sample database was analyzed for patients admitted with AIS (2012-2022). Data collected included demographics, socioeconomic status, comorbidities, hospital characteristics (location and U.S. region), length of stay (LOS), and discharge disposition. Patients were categorized as either direct admissions (DA) or inter-hospital transfers (IHT). Propensity-score matching (PSM) was applied to balance comorbidities and severity between the two groups. Primary outcomes included LOS, hospitalization costs, and discharge to home or inpatient rehab. Multivariable logistic regression models were built to assess associations between IHT and each outcome. Among 1,610,674 AIS admissions, 173,522 (10.8%) involved IHT. Compared to the DA group, IHT patients were younger (68 [58–78] vs. 72 [62–82] years), more frequently male (53.5% vs. 50.0%), White (70.6% vs. 67.9%), and more likely to have private insurance (21.4% vs. 17.5%), <i>p</i> &lt; 0.01 for all. The majority of IHTs were directed to teaching hospitals (85.7%), followed by urban non-teaching (10.7%) and rural hospitals (3.6%). Temporal analysis revealed a significant increase in IHT over the study period (β: 0.523, <i>p</i> &lt; 0.01), with all U.S. regions except East South Central showing upward trends. After 1:1 PSM, IHT was independently associated with prolonged LOS (β: +1.2 (days), 95%CI: 1.1–1.3), higher hospitalization costs (β: +8,560 ($), 95%CI: 7,980–9,140), lower odds of discharge to home or inpatient rehab (OR:0.715, 95%CI: 0.705–0.726, <i>p</i> &lt; 0.001), <i>p</i> &lt; 0.01 for all. Inter-hospital transfers among AIS patients have increased significantly over the past decade, predominantly involving transfers to teaching hospitals. IHT facilitates access to advanced stroke care for more complex and severe AIS patients, as reflected by greater resource utilization.