Sterile Leukocytosis Predicts Hemorrhagic Transformation in Arterial Ischemic Stroke: A National Inpatient Sample Study

Objective: Hemorrhage transformation (HT) is a known complication of arterial ischemic stroke (AIS). In addition, it is known that the increase of proinflammatory immune cells in the brain tissue after AIS predict worse outcomes. However, it is not clear whether inflammation due to preceding or post-stroke infections affect outcomes and moreover, if systemic inflammatory markers could be useful as a clinical prediction tool for HT post-stroke. Therefore, our objective was to assess the association between systemic pro-inflammatory profile in AIS patients with HT and in-hospital mortality that did not course with acute infections during hospitalization. Methods: This study was conducted using the 2016 and 2017 National Inpatient Sample (NIS) with International Classification of Diseases (ICD-10) codes. Multivariate logistic regression was used to examine the association between HT and in-hospital mortality with pro-inflammatory anomalies of white blood cells (WBCs) in AIS patients. Exclusion criteria comprised patients with under 18 years old, and with a diagnosis of gastrointestinal, urogenital, respiratory infection, bacteremia, viral infection, sepsis, or fever. Results: A total of 212,356 patients with AIS were included in the analysis. 422 (0.2%) patients had a HT and 10,230 (4.8%) patients died during hospitalization. The most common WBC pro-inflammatory marker was leukocytosis with 6.9% (n=29/422) of HT and 5.5% (n=560/10,230) of patients that died during hospitalization. After adjusting for socio-demographic, comorbidities and treatment factors, leukocytosis was found to be an independent risk factor for both outcomes, HT [OR = 1.5, 95% CI: 1-2.3, p=0.024] and, in-hospital mortality [OR = 1.5, 95% CI: 1.3-1.6, p < 0.001]. Conclusion: Sterile leukocytosis is a potential clinical prediction tool to determine which patients are at higher risk of developing HT and die during hospitalization.