Comparative Analysis of Serum Biochemical Markers, Age, and Functional Independence in COVID-19 and Guillain-barré Syndrome Patients: A Single-site Retrospective Study

Objective: To assess the similarities and differences of patients with Guillain-Barré Syndrome (GBS) and COVID-19. Patients admitted with COVID-19 and GBS often experience a significant functional decline at illness onset due to decreased mobility, which may be captured by various serum markers.

Design: Single Site Retrospective Review
Setting: Gaylord Hospital, a 137-bed long-term acute care hospital (LTACH) in Wallingford, Connecticut, USA.

Participants: Patients admitted to Gaylord Hospital between 2/17/2020 and 2/10/2021 with a primary diagnosis of GBS or COVID-19.

Interventions: N/A
Main Outcome Measure(s): Demographics, serum creatinine, albumin, total protein, and the CMS Continuity Assessment Record and Evaluation (CARE) dataset section on mobility independence.
Result: In males, creatinine levels significantly differed between diagnoses at admission (p=0.0074) and discharge (p=0.0213); no in-group changes were observed over time (p≥0.1614). In contrast, females observed no between-group differences in creatinine at admission or discharge (p≥0.3257). Interestingly, COVID-19 females, but not GBS females, demonstrated a significant increase in creatinine from admission to discharge (p=0.0032). Both groups demonstrated significant in-group mobility independence improvements from admission to discharge (p≤0.0138). Between groups, COVID males demonstrated greater mobility independence than GBS males at admission (p=0.0408) and discharge (p < 0.0001). Similarly, COVID females demonstrated greater mobility independence than GBS females at discharge (p < 0.0001), but not at admission (p=0.0969). Multiple linear regression with robust standard error correction indicated that diagnosis (p < 0.001), creatinine (p < 0.01), and age (p < 0.001) were significant predictors of functional independence; gender, albumin, and total protein levels were not significant predictors at admission. Additionally, the interaction term between creatinine levels and diagnosis was significant admission, indicating that the effect of creatinine levels on functional independence was significantly decreased when patients had COVID (p=0.022). At discharge, diagnosis and age were key predictors of mobility independence (p < 0.001), while race, BMI levels, albumin, EGFR, creatinine, albumin, total protein, gender, and the interaction of creatinine and diagnosis were not significant predictors (p≥0.1786).

Conclusions:
This analysis showed that diagnosis and age are key predictors of mobility independence in GBS and COVID patients at admission and discharge. Furthermore, creatinine levels are a significant predictor only at admission, likely due to variability introduced by COVID-19. The adjusted R² from the multiple regression analysis suggests that the model fit is limited, indicating that other variables may influence functional independence scores.