Correlation between Systemic Inflammatory Response Index (SIRI) and disease severity in patients with Guillain-Barré syndrome

Abstract

Background: Guillain-Barré syndrome (GBS) is a peripheral neuropathy with variable clinical severity, and in severe cases, it can lead to significant neurological dysfunction and respiratory failure. In this study, we evaluated the relationship between the Systemic Inflammatory Response Index (SIRI), derived from a complete blood count, and neurological severity in patients with GBS.

Methods: The data of 40 consecutive patients diagnosed with definitive GBS between January 1, 2021, and March 1, 2023, at a tertiary care center were retrospectively analyzed. Demographic data, vital signs at presentation, and laboratory results were recorded. SIRI (neutrophils × monocytes / lymphocytes) was calculated from initial blood counts. Disease severity was defined using the Hughes Functional Grading Scale (HFGS) at the worst disease stage, with a score of ≥4 considered a “severe” clinical presentation. The performance of SIRI in predicting severe GBS was evaluated using receiver operating characteristic (ROC) curve analysis, the Youden index, and logistic regression.

Results: The median age of the patients was 58 years (interquartile range: 42–73), and 52% were male. The median SIRI was significantly higher in the severe group (n = 27, 68%) compared to the mild group (n = 13, 32%) [1.69 (1.33–2.85) vs. 1.39 (0.90–2.02); p = 0.013]. A moderate positive correlation was found between SIRI and the worst HFGS score (r = 0.554, p < 0.001). In ROC analysis, at a cut-off value of ≥1.43, SIRI predicted severe GBS with 77.4% sensitivity and 77.8% specificity (area under the curve = 0.771, Youden index = 0.552). In multivariate logistic regression, SIRI ≥ 1.43 (odds ratio = 5.8, 95% confidence interval: 2.0–17.0), initial HFGS score ≥ 3, and age ≥ 60 years remained independent predictors of a severe clinical course.

Conclusion: The SIRI value at presentation is an independent and easily applicable biomarker for predicting neurological severity in GBS. The SIRI threshold of ≥1.43 may assist in identifying patients requiring early intensive care monitoring or aggressive treatment; however, these findings should be validated in multicenter, prospective studies.