Serum S100β as a predictor of severity and outcomes for mixed subtype acute ischaemic stroke

INTRODUCTION Serum S100 beta levels are mostly used for predicting outcomes of large-vessel stroke. Its application to mixed subtypes of acute ischaemic stroke (AIS) has been limited. METHODS Patients with mixed subtypes of AIS who were aged over 18 years and presented within 24 hours of stroke onset were consecutively enrolled. Serum S100 beta levels at presentation (S100 beta(b)) and 72 hours (S100 beta(72hrs)), and corresponding National Institutes of Health Stroke Scale (NIHSSb and NIHSS72hrs, respectively) scores were assessed. Stroke outcomes were evaluated using the modified Rankin Scale (mRs) at 30 days (mRs(30)) and 90 days (mRs(90)). Correlations between S100 beta(b), and S100 beta(72hrs), as well as differences between the two (Delta S100 beta) and the corresponding NIHSS, mRs(30) and mRs(90) scores, were evaluated (p < 0.05). RESULTS 35 patients were eligible for analysis. On univariate analysis, stroke outcomes had a significant association with S100 beta(b), S100 beta(72hrs), NIHSSb, NIHSS,Thrs and Delta S100 beta. Both S100 beta(b), and S100 beta(72hrs) correlated with corresponding NIHSS values (rho(b) = 0.51, p < 0.001; rho(72hrs) = 0.74, p < 0.001), mRs(30) (rho(b) = 0.58, p < 0.001; rho(72hrs) = 0.72, p < 0.001) and mRs(90) (rho(b) = 0.51, p = 0.002; rho(72hrs) = 0.68, p < 0.001). Correlations existed between Delta S100 beta and mRs(30) (rho = 0.74, p < 0.001) and mRs(90) (rho = 0.71, p < 0.001). Practical cut-off points for unfavourable outcomes (mRs 3-6) were S100 beta(72hrs) > 0.288 mu g/L (sensitivity 92.3%, specificity 86.4%) and Delta S100 beta > 0.125 mu g/L (sensitivity 100%, specificity 81.8%). CONCLUSION High serum S100 beta is associated with unfavourable outcomes for mixed subtype AIS. Cut-off values of S100 beta(72hrs) and Delta S100 beta were optimal for predicting unfavourable stroke outcomes.