Neutrophil to lymphocyte ratio for predicting delayed neurologic sequelae caused by carbon monoxide poisoning: A...

This study summarized and analyzed the prognostic value of the neutrophil to lymphocyte ratio (NLR) for delayed neurologic sequelae (DNS) caused by carbon monoxide (CO) poisoning.

PubMed, Embase, Cochrane Library, Web of Science, ScienceDirect, and China National Knowledge Infrastructure Database were searched to identify relevant articles from their inception to February 2026. The odds ratio and its 95% confidence interval (CI), area under the curve, meta-regression analysis, sensitivity analysis, and publication bias for NLR were estimated to predict DNS.

Eight studies were included, involving 1757 patients with acute CO poisoning, among whom 382 cases (21.7%) developed DNS. The pooled results show that NLR was related to DNS (odds ratio = 14.67, 95% CI: 8.26-26.04, P < .001) and had high heterogeneity (I2 = 65.1%, P = .005). The area under the curve of NLR for predicting DNS was 0.88 (95% CI: 0.85-0.91), with a sensitivity of 86% and a specificity of 72%. Subgroup analysis indicated that study design may be the source of heterogeneity. Sensitivity analysis suggested the robustness of the results. Deek's test did not detect significant publication bias (P = .24).

Current evidence indicates that an elevated NLR is associated with an increased risk of DNS after acute CO poisoning, supporting its potential utility as a prognostic marker. However, because the included studies showed substantial heterogeneity and were predominantly retrospective, these findings should be interpreted with caution and require validation in high-quality prospective studies. NLR should therefore be considered an auxiliary tool for risk stratification rather than an independent diagnostic method. Its principal clinical value may lie in resource-limited settings where advanced monitoring is not feasible.