At the time of enrollment, baseline demographic information and clinical characteristics were collected by our trained investigators, including age, sex, medical history (hypertension, diabetes, antihypertensive medication use, smoking and alcohol use), and time from symptom onset to admission. The vital signs were recorded on admission, including systolic blood pressure (SBP), diastolic blood pressure (DBP), body temperature, respiratory rate, and heart rate. For descriptive purposes, the time from onset to admission was divided into 3 groups: <6 h, 6–24 h, and 24–72 h. At baseline, stroke severity was assessed using the GCS and NIHSS score (ranging from 0 to 42, with higher scores denoting more severe neurologic deficits). The routine laboratory examinations (including white blood cell count) and CT scans of the brain were performed in accordance with standardized procedures on admission. In-hospital infection was defined as diagnosis of a clinical infection during the hospital stay that was documented in the electronic medical record with classified as pneumonia, urinary tract infection, bloodstream infection, and central nervous system infection. Additionally, we recorded whether the patients underwent any brain surgery during their hospitalizations, including decompressive craniectomy, aspiration of hematoma, craniotomy evacuation of hematoma, and lateral ventriculopuncture drainage.