Objectives: The neutrophil-to-lymphocyte ratio (NLR) in whole blood is an indicator of prognosis in several disorders, however its predictive value in the CSF of hydrocephalus patients has not been studied. This study aimed to determine the prognostic relevance of NLR at admission and its implications for clinical outcomes in patients with hydrocephalus treated with an external ventricular drain (EVD).

Methods: This retrospective study examined consecutive individuals with hydrocephalus who were admitted to an adult ICU in a single center between 2020 and 2022.  Patient demographics, clinical characteristics, laboratory data, and computed tomography (CT) scans were gathered.  ROC curve analysis was used to identify the optimal NLR and clinical variable cutoff values for mortality. Univariate and multivariate logistic regression analysis was carried out to assess the independent impact of variables on mortality.

Results: We included 40 patients with hydrocephaly in the present study. There were 24 males (60%) and 16 females (40%) patients, with an average age of 51.68 ± 16.34 years. NLR was considerably higher in the dead group than the alive (8.49 ± 6.53 vs 5.05 ± 3.78) (P=0.027). In a model of ROC analysis, NLR (AUC 0.702, 95% CI: 0.537 to 0.836; P = 0.0171), Age (AUC 0.674; 95% CI: 0.507 to 0.813; p= 0.0496), underlying disease (AUC 0.650; 95% CI: 0.483 to 0.794; p= 0.0126), and level of consciousness level (AUC 0.946; 95% CI: 0.825 to 0.993; p<0001) were significantly associated with mortality. The best predictive threshold of the NLR was 8.88 (sensitivity, 40%; specificity, 100%).

Conclusion: In the current research, a high NLR (>8.88) in CSF was associated with an increased risk of mortality in individuals with hydrocephalus. When paired with a GSC score of <8, admission NLR > 8.88 considerably increases the accuracy of predicting outcomes following EVD.