Blood neurofilament light concentration at admittance: a potential prognostic marker in COVID-19

Objective To test the hypotheses that serum concentrations of neurofilament light chain protein (NfL) and glial fibrillary acidic protein (GFAp) can serve as biomarkers for disease severity in COVID-19 patients. Methods Forty-seven inpatients with confirmed COVID-19 had blood samples drawn on admission for assessing serum biomarkers of CNS injury by Single molecule array (Simoa), NfL and GFAp. Concentrations of NfL and GFAp were analyzed in relation to symptoms, clinical signs, inflammatory biomarkers and clinical outcomes. We used multivariate linear models to test for differences in biomarker concentrations in the subgroups, accounting for confounding effects. Results In total, 21 % (n=10) of the patients were admitted to an intensive care unit, whereas the overall mortality rate was 13 % (n=6). Non-survivors had higher serum concentrations of NfL (p<0.001) than patients who were discharged alive both in adjusted analyses (p=2.6 x 10-7) and unadjusted analyses (p=0.001). The concentrations of NfL in non-survivors increased over repeated measurements whereas the concentrations in survivors were stable. Significantly higher concentrations of NfL were found in patients reporting fatigue, while reduced concentrations were found in patients experiencing cough, myalgia and joint pain. The GFAp concentration was also significantly higher in non-survivors than survivors (p=0.02). Conclusion Increased concentrations of NfL and GFAp in COVID-19 patients on admission may indicate increased mortality risk. Measurement of blood biomarkers for nervous system injury can be useful to detect and monitor CNS injury in COVID-19.