Temporal Pattern and Clinical Value of Serum GFAP in Acute Ischemic Stroke: Results from Two Prospective German Cohorts

Serum glial fibrillary acidic protein (sGFAP) is an astroglial biomarker preliminarily investigated in acute ischemic stroke (AIS). We aimed to investigate its temporal pattern and clinical value in two German AIS cohorts. Using immunoassay, we measured sGFAP concentrations in 952 samples of 572 AIS patient and 32 samples of controls recruited in Halle [AIS n = 102, age: 70.9 (± 15.9) years, 52.0% males; controls n = 32, age: 47.6 (± 18.8) years, 59.4% males] and Würzburg [AIS n = 470, age 74.6 (± 12.8) years, 48.3% males]. In AIS patients, we stratified samples according to the time from symptom onset to blood sampling, namely at D1 (< 24 h), D2 (24-48 h), D3 (48-72 h) and D5-7 (96-144 h), and tested associations between biomarker levels and clinical data. sGFAP level was increased at all timepoints after AIS compared to control subjects (p < 0.001, age-adjusted p < 0.01) with significant changes over time (D1 < D2< D3 ≥ D5-7). We found increased sGFAP concentrations in AIS patients who had altered mental status on admission (p < 0.01), hemorrhagic transformation of AIS (HT, p < 0.001) as well as systemic infections such as pneumonia (p < 0.001). Higher D1 sGFAP concentrations were associated with higher likelihood of modified Rankin Scale > 2 at 3 months [aOR = 1.015 (95%CI = 1.005-1.025), p = 0.004] and a shorter survival at longest follow-up (median: 576 days, max 922 days) [highest tertile vs. lowest tertile HR = 2.94 (95%CI = 1.21-7.17), p = 0.018]. sGFAP is elevated after AIS and of informative value regarding the risk HT and infections, as well as on the clinical outcome at follow-up.