Predictive value of neutrophil to lymphocyte ratio (NLR) for epileptic seizures: a systematic review and meta- analysis

Abstract

The neutrophil-to-lymphocyte ratio (NLR) is a commonly used biomarker for inflammation and is typically elevated in patients experiencing epileptic seizures making it a valuable diagnostic indicator in clinical practice. However, there is no consensus on the predictive value of NLR in patients with epileptic seizures. Given this controversy, we conducted a meta-analysis to clarify the predictive value of NLR for epileptic seizures. We conducted a comprehensive literature search in the PubMed, Embase, Cochrane Library, and Web of Science databases, systematically reviewing the literature from January 1, 2000, to May 1, 2024, and determined the eligible studies. NLR values and corresponding sample sizes were extracted from each included study, and a random effects model was used for the meta-analysis. Sensitivity analysis was performed to investigate heterogeneity. Subgroup analysis was conducted to explore the sources of heterogeneity. Egger's test was also used in this meta-analysis to investigate publication bias. After a comprehensive literature search and screening, we included 16 studies in our meta-analysis. The pooled results indicate that NLR levels in the epileptic seizure group are significantly higher compared to the non-seizure group (random effects model, SMD 0.49, 95% CI: 0.31, 0.67, P < 0.0001). Heterogeneity tests revealed significant heterogeneity (I² = 82%). Sensitivity analysis results indicate that our findings are robust to the influence of individual studies. Subgroup analysis results suggest that the testing time of NLR and mean/median age are sources of heterogeneity. Egger's test shows no significant publication bias in this meta-analysis. This is the first meta-analysis to demonstrate that NLR, as a biomarker, has good predictive value for epileptic seizures. The meta-analysis has been registered in the PROSPERO database (registration number CRD42024550918).