ABO blood type is not a risk factor of outcome in aneurysmal subarachnoid hemorrhage patients

Background The association between ABO blood types and outcome of aneurysm subarachnoid hemorrhage (aSAH) has not reached a conclusion. This study was performed to testify the difference of outcome between ABO blood types. Methods 663 aSAH patients hospitalized in the West China hospital were enrolled. The association between ABO blood types and outcomes including mortality and delayed cerebral ischemia (DCI) was verified by the univariate and multivariate logistic regression. Glasgow Outcome Score (GOS) at discharge, length of ICU stay, length of hospital stay were also compared between different ABO blood types. Results 663 aSAH patients were divided into four groups according to their ABO blood types: AB type (46, 6.9%), A type (211, 31.8%), B type (169, 25.4%),O type (237, 35.7%). The GCS, WFNS, Hunt Hess, modified Fisher, aneurysm location and incidence of intraventricular hemorrhage did not show different distribution among ABO blood types. Among four coagulation indexes, only the activated partial thromboplastin time (APTT) showed different distribution among ABO blood types (p < 0.001). The AB group had the lowest level of APTT while O group had the highest level of APTT. Outcomes including delayed cerebral ischemia, mortality, GOS, length of ICU stay, and length of hospital stay did not show any significant differences among ABO types. Univariate logistic regression showed the ABO blood type was not associated with the development of DCI (p = 0.654) and the mortality (p = 0.430). The multivariate logistic regression showed ABO blood types were still not associated with DCI and mortality after adjusting confounding effects of significant risk factors. Conclusions The ABO blood type is not associated with the prognosis of aSAH patients. ABO blood types may not be helpful on risk stratification of aSAH.