This study aims to systematically review the existing literature and perform a meta-analysis to evaluate the prevalence of hyponatremia among Guillain Barre Syndrome (GBS) patients and its relationship with disease prognosis. We comprehensively searched PubMed, Embase, Medline, Web of Science, Science Direct, and the Cochrane Library databases from 1995 to 2024 for observational studies on the prevalence of hyponatremia in GBS. The meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines. Heterogeneity among the included studies was calculated with the I
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for each analysis. We used the Comprehensive Meta-Analysis software (Version 3.3.070; Biostat, Englewood, USA). Eight observational studies met our inclusion criteria. The meta-analysis showed that the pooled prevalence of hyponatremia among GBS patients was 12% (95% CI: 0.107-0.149). The results exhibited high heterogeneity (I² = 99%), indicating significant variability among the studies. Hyponatremia rates reported in these eight studies ranged from 11.5% to 48% in GBS patients. The prevalence of hyponatremia was found to be 12% in GBS patients, which is relatively lower compared to some reports. Hyponatremia was found to be associated with prolonged hospital stay, mortality, and mechanical ventilation as poor prognostic factors. Further prospective studies are needed to elucidate the mechanisms underlying hyponatremia in GBS and to develop targeted interventions to address this issue.