Re-evaluating Risk Factors, Incidence, and Outcome of Aneurysmal and Non-aneurysmal Subarachnoid Hemorrhage: A Population-based Registry Study from Isfahan Province, Iran, 2016-2020.

Abstract

Subarachnoid hemorrhage (SAH) is one of the world's most life-threatening types of stroke. SAH can be classified into two main categories, aneurysmal (aSAH) and non-aneurysmal SAH (naSAH). In the present study, we aimed to prospectively evaluate SAH and its subcategories incidences, risk factors (RF), complications and outcomes in central Iran. All SAH patients diagnosed between 2016-2020 were included in Isfahan SAH Registry (ISR). Demographic, clinical characteristics, incidence rates (based on age categories), and laboratory/imaging findings were collected and compared between aSAH and naSAH subgroups. Complications during hospital stay and outcomes were also analyzed. Binary logistic regression analysis was performed to investigate the predictors of aSAH versus naSAH. Kaplan-Meier curves and Cox regression were used to evaluate the survival probability. A total of 461 SAH patients were included through ISR. The SAH annual incidence rate was 3.11 per 100,000 person-years. aSAH had higher incidence rate than naSAH (2.08/100,000 versus 0.9/100,00 person-years). In-hospital mortality was 18.2% with no significant difference between aSAH and naSAH subgroups. Hypertension (p=0.003) and smoking (p=0.03) were significantly associated with aSAH, whereas DM (p<0.001) was more associated with naSAH. After Cox regression analysis, there were higher hazard ratios for reduced in-hospital survival in conditions including altered mental status, Glasgow coma scale ≤13, rebleeding and seizures. This study provided an updated estimation of SAH and its subgroups incidences in central Iran. Risk factors for aSAH are comparable to the ones reported in the literature. It is noteworthy that DM was associated with a higher incidence of naSAH in our cohort.