Association Between the Time from Onset to Nadir and the Clinical Characteristics in Patients with Guillain-Barré Syndrome.

Objective This study aimed to elucidate the clinical parameters of Guillain-Barré syndrome (GBS), including the short-term outcomes, associated with the time from onset to nadir (TON). Methods This single-center retrospective observational study divided patients with GBS into rapidly and nonrapidly progressive groups based on the TON (nadir reached within 7 days or after 7 days, respectively). The clinical features and outcomes were compared between the groups. Patients or Materials A total of 26 patients with GBS who underwent antiganglioside antibody testing between April 2015 and May 2025 were enrolled. The short-term outcomes were evaluated using the Hughes Functional Grading Scale (HFGS) scores at nadir and at discharge. Results The rapidly and nonrapidly progressive groups included 17 and 9 patients, respectively. Posttreatment deterioration and the need for mechanical ventilation were observed only in the rapidly progressive group, with significantly higher frequencies than in the nonrapidly progressive group (p = 0.009 and p = 0.023, respectively). Furthermore, mean HFGS scores at nadir were significantly higher in the rapidly progressive group (3.8 vs. 2.6; p = 0.018), whereas no significant differences were observed at admission or discharge (p = 0.21 and p = 0.14, respectively). Conclusion Regarding short-term outcomes, patients with shorter TON experienced greater disease severity at nadir but ultimately showed discharge outcomes comparable to those of patients with longer TON. In GBS, TON may serve as a predictor of short-term disease severity, but it does not necessarily correlate with the outcomes at discharge.