S100β Protein as a Predictor of Poststroke Functional Outcome: A Prospective Study.

Background: Stroke is one of the leading causes of disability worldwide. Early prediction of poststroke disability using clinical models is of great interest, especially in the rehabilitation field. Although some biomarkers and neuroimaging techniques have shown potential predictive value, there are still insufficient data to support their clinical utility in predicting poststroke functional recovery. We aimed to assess the value of serum biomarkers (C-reactive protein [CRP], D-dimer, fibrinogen, and S100β protein) in predicting medium-term (12 weeks) functional outcome in patients with acute ischemic stroke.

Methods: This is an observational, prospective study in a sample of patients hospitalized for ischemic stroke (N = 131). Peripheral blood levels of biomarkers of interest were determined at admission (CRP, D-dimer, and fibrinogen) or at 48 hours poststroke (S100β protein). Functional status was accessed at 48 hours and 12 weeks poststroke using the modified Rankin Scale (mRS).

Results: S100β protein levels measured at 48 hours were significantly associated with mRS scores at 12 weeks (odds ratio = 1.005, 95% confidence interval [CI] [1.005-1.007]; P <.001). This association was not seen for the remaining biomarkers of interest. The S100β cutoff for poor functionality at 12 weeks was 140.5 ng/L or more (sensibility 83.8%; specificity 71.4%; area under the curve = .80, 95% CI [.722, .879]).

Conclusions: S100β levels in peripheral blood at 48 hours poststroke reflect acute stroke severity and predict functional outcome at 12 weeks with a cutoff value of 140.5 ng/dL. The value of S100β as predictor of functional recovery after stroke should be emphasized in further clinical research and clinical practice.