Serum Folate Correlates with Severity of Guillain-Barré Syndrome and Predicts Disease Progression

The aim of this study was to determine the associations between serum folate level and the clinical course and severity of Guillain-Barré syndrome (GBS). We retrospectively enrolled 112 pairs of GBS patients and age- and sex-matched healthy controls with measured serum folate levels. On admission, 21 (18.9%) GBS patients had folate deficiency, of which only two were female patients. Patients with normal folate levels had a shorter disease progression than those with folate deficiency (median progression duration: 6 versus 13 days, p < 0.001). Serum folate levels on admission were correlated with progression duration and Medical Research Council (MRC) sum score in the upper limbs at nadir (r = -0.261, p = 0.005; r = -0.208, p = 0.03) but not with the duration of hospital stay or GBS disability score (p > 0.05). Logistic regression analysis revealed that normal folate levels on admission were an independent predictor of faster GBS progression, along with younger age, intact deep sensation, and a lower MRC sum score on admission. These results show that serum folate levels are correlated with the progression duration and severity of GBS. Further studies are required to confirm the potential of folate level as a biomarker for GBS prognosis.