Association between hospital characteristics and 30-day mortality after acute stroke: a multi-level study in South Korea

Background: Stroke is the fourth leading cause of death in South Korea and shows substantial regional variation in mortality.Although timely medical care can reduce premature death and disability, few studies have examined hospital-level factors associated with stroke outcomes.This study aimed to identify hospital-level factors associated with acute stroke mortality and to determine optimal resource levels for high-quality care.Methods: This nationwide retrospective cohort study analyzed patients with acute stroke in South Korea from 2018 to 2020 using the National Health Insurance System claims database and Medical Resource Report data.The outcome was all-cause mortality within 30 days of admission.Individual-level variables included sociodemographic characteristics, the Charlson Comorbidity Index, and the Stroke Severity Index.Hospital-level variables included the number of beds, specialists, neurologists/neurosurgeons, and nurses, as well as accreditation level and stroke center designation status.Hierarchical logistic regression using generalized linear mixed models and change-point analysis were used to determine optimal resource thresholds.Results: Change-point analysis identified critical thresholds associated with reduced mortality: 600 hospital beds, 25 specialists, 8 neurologists and neurosurgeons, and 540 nurses.Multilevel analysis showed that patients treated in hospitals with fewer than 600 beds (odds ratio [OR], 1.128; p=0.0129), fewer than 8 neurologists and neurosurgeons (OR, 1.151; p<0.0001), and no stroke intervention capacity (OR, 1.052; p<0.0001) had a significantly higher risk of 30-day mortality. Conclusions:The identified thresholds provide baseline data that may guide development of medical systems tailored to local characteristics and support the timely delivery of highquality medical services.These findings suggest that each HSA should include hospitals that meet minimum resource standards to improve stroke outcomes.