Abstract TP009: Old age, history of stroke, emergency admission, and pre-hospital antiplatelet therapy as independent risk factors for in-hospital ischemic stroke among 36,595 hospitalized patients

Background and Purpose: In-hospital onset stroke (IHOS) is associated with poorer outcomes than out-of-hospital onset stroke (OHOS), primarily due to delays in symptom recognition and neuroimaging, and lower rates of intravenous thrombolysis and mechanical thrombectomy. However, the clinical characteristics and risk factors for IHOS remain insufficiently defined. We aimed to determine the incidence and independent risk factors for IHOS in a large cohort of hospitalized patients. Methods: We retrospectively reviewed all patients aged ≥18 years admitted to Kumamoto University Hospital between April 2023 and March 2025. Admission diagnoses and clinical data were extracted using ICD-10 codes. Patients were categorized into two groups: those who developed ischemic stroke during hospitalization (IHOS group) and those who did not (non-IHOS group). Clinical characteristics were compared between groups, and multivariate logistic regression was used to identify independent risk factors for IHOS. Results: Among 36,595 patients (median age 68 years; men 51.6%), 104 (0.3%) developed IHOS. Compared with the non-IHOS group, the IHOS group had higher rates of older age (median 74 vs 68 years; P <0.001), hypertension (66.3% vs 47.1%; P <0.001), atrial fibrillation (14.4% vs 7.8%; P =0.025), history of stroke (4.8% vs 0.1%; P <0.001), cancer (14.4% vs 8.4%; P =0.034), warfarin use (8.7% vs 2.4%; P <0.001), antiplatelet use (66.3% vs 15.2%; P <0.001), and emergency admission (19.2% vs 4.2%; P <0.001). Multivariate analysis identified older age (OR 1.018; 95% CI, 1.001–1.034), history of stroke (OR 12.284; 95% CI, 4.652–32.442), antiplatelet use (OR 7.737; 95% CI, 4.993–11.988), and emergency admission (OR 3.036; 95% CI, 1.835–5.025) as independent risk factors for IHOS. Conclusions: Older age, history of stroke, emergency admission, and pre-hospital antiplatelet therapy were independent risk factors for in-hospital ischemic stroke. Early identification of high-risk patients may facilitate preventive strategies and timely intervention.