Epidemiological and Clinical Profile of Patients With Non-traumatic Subarachnoid Hemorrhage in a Brazilian Referral Hospital

Introduction Non-traumatic subarachnoid hemorrhage (SAH) is a severe neurological condition and remains a public health concern with high morbidity and mortality. Aneurysmal rupture is the primary cause, with modifiable risk factors such as hypertension and smoking playing significant roles. The objectives of this study were to describe the epidemiological, clinical, radiological, and management profile and short-term in-hospital outcomes (mortality and functional status at discharge) of patients with non-traumatic SAH treated at a tertiary neurosurgical referral center in São Carlos, Brazil, between 2016 and 2022, and, secondarily, to examine exploratory, unadjusted associations between baseline clinical severity, in-hospital complications, management strategies (conservative management, coiling, or clipping), and in-hospital outcomes. Methods We conducted a retrospective observational cohort study including 125 consecutive patients with non-traumatic SAH. Cases were identified through screening of International Classification of Diseases, Tenth Revision (ICD-10) codes, followed by manual chart review and imaging confirmation. Demographic data, vascular risk factors, clinical presentation, neuroimaging findings, treatment modalities (clinical management, endovascular coiling, or surgical clipping), complications, and in-hospital outcomes (mortality and Modified Rankin Scale (mRS) score at discharge) were extracted from electronic medical records. Descriptive statistics were used to summarize the cohort, and unadjusted comparisons were performed using the Mann-Whitney U test, Kruskal-Wallis test, and chi-square test, with a significance level of p < 0.05. Results The mean age of patients was 56 years, and 70% of patients were female. Hypertension (51%), smoking (26%), and alcohol consumption (16%) were common risk factors. Aneurysmal SAH accounted for 65% of cases, predominantly involving the anterior communicating artery. The overall in-hospital mortality rate was 45% (56/125). In unadjusted analyses, in-hospital death was more frequent among patients requiring endotracheal intubation, ventricular shunting, or who developed hydrocephalus, and less frequent among those who received nimodipine. Functional outcome at discharge was poor, with 45% of patients classified as mRS 6 (death) and 15% having moderate-to-severe disability. Conclusion In this Brazilian tertiary referral center, non-traumatic SAH predominantly affected middle-aged women, with hypertension and smoking as the main modifiable risk factors. In-hospital mortality was high and was associated with markers of greater clinical severity and complications, such as mechanical ventilation, hydrocephalus, and the need for ventricular shunting. In unadjusted, exploratory analyses, patients undergoing aneurysm coiling or clipping had more favorable crude outcomes than those managed conservatively; however, these differences are likely influenced by baseline severity and treatment selection and should not be interpreted as evidence of treatment efficacy. These findings underscore the need for improved early recognition, control of vascular risk factors, and expanded access to specialized neurosurgical and neurocritical care in resource-limited settings.