The correlation of temporal changes of neutrophil-lymphocyte ratio with seizure severity and the following seizure tendency in patients with epilepsy

Abstract

Background: Changes in the neutrophil-lymphocyte ratio (NLR) has been reported to be associated with epilepsy. Here we aim to investigate the correlation of temporal changes of NLR level with seizure severity and the follow-up seizure attacks in patients with epilepsy (PWE).

Methods: We performed a retrospective analysis of the laboratory data including leukocyte count and NLR within 24 h of acute seizure and during the follow-up period of 5-14 days after acute seizure (NLR1, NLR2, respectively) in 115 PWE, and 98 healthy individuals were included as controls in this study. The correlation of laboratory data with seizure types, etiology of epilepsy, anti-seizure drugs (ASDs), seizure severity, and the follow-up seizure attacks in PWE was studied.

Results: Leukocyte count (P < 0.001) and NLR level (P < 0.001) were found significantly different between PWE and controls. On the other hand, a multivariable logistic regression analysis showed that NLR1 level (OR = 2.992, P = 0.001) and admission leukocyte (OR = 2.307, P = 0.002) were both independently associated with acute epileptic seizures. Especially, higher NLR1 level was significantly associated with status epileptics (P = 0.013) and recurrent seizures after admission (P < 0.001). Furthermore, the multivariable logistic regression analysis indicated that higher NLR1 was a predictor for the tendency of the following recurrent seizure attacks (OR = 1.144, P = 0.002). NLR2 was inversely correlated with ASDs taken (P = 0.011). Levels of NLR1 (r = 0.441, P < 0.001) and NLR2 (r = 0.241, P = 0.009) were both positively correlated with seizure severity.

Conclusions: Seizures were correlated with the alterations of systemic inflammation reflected by leukocyte and NLR. NLR1 and admission leukocyte were both independently associated with acute epileptic seizures. Higher NLR1 was associated with status epilepticus and independently predicted the tendency of the following epileptic seizures. NLR2 was significantly associated with ASDs taken. Besides, NLR may be used as a biomarker for seizure severity.

Keywords: inflammation; neutrophil-lymphocyte ratio; recurrent seizure attacks; seizure severity; status epilepticus.

Figure 1

ROC curve analysis of the prediction for the following recurrent seizure attacks based on NLR1. The best cut-off value of NLR1 was 5.56, area under the curve (AUC) = 0.717, P < 0.001, 95% CI: 0.611–0.823, sensitivity: 73%, and specificity: 71%.

Figure 2

The difference in NLR levels at admission (NLR1, within 24 h of acute seizure) and follow-up period (NLR2, 5–14 days after admission) in PWE. Neither NLR1 nor NLR2 level was different between patients with newly diagnosed epilepsy and those with chronic epilepsy (A). There was no significant difference in NLR level between patients with idiopathic epilepsy and those with secondary epilepsy (B), and there was no significant difference in NLR level among the five categories of patients with focal epilepsy (C). NLR2 level in patients on treatment with ASDs was lower than those in patients on no treatment with ASDs (D). NLR1 level in patients with SE was higher than that in patients with self-limited seizures (E). Group comparison was done by Mann-Whitney U test. *P < 0.05.

Figure 3

Levels of NLR were positively correlated to NHS3 scores in PWE at admission (within 24h of acute seizure) (A) and follow-up period (5–14 days after admission) (B). Correlation analysis was done by Spearman's correlation.