RESUMO
Objective:To evaluate the predictive value of neutrophil-to-lymphocyte ratio (NLR) for adult severe tetanus by comparing the NLR in patients with severe and mild tetanus.Methods:A total of 65 adult tetanus patients from the Linyi Central Hospital from January 2009 to December 2020 were enrolled. The patients were divided into two groups including mild group and severe group according to the Ablett classification. The general conditions, laboratory data, and NLR of patients in two group were retrospectively compared using independent samples t test. Multivariate logistic regression analysis was used for the analysis of risk factors for severe tetanus. Spearman correlation method was used for the analysis of the correlation between risk factors and Ablett grades. Receiver operator characteristic (ROC) curve was used for the evaluation of the predictive value. Results:Among the 65 tetanus cases, 34 was in mild group and 31 in severe group. The latency period of patients in severe group was (7.00±3.19) d, which was shorter than that in mild group ((9.18±2.59) d), and the difference was statistically significant ( t=3.03, P=0.004). The NLR of patients in severe group was 4.251±1.936, which was higher than that of mild group (2.533±1.026) , and the difference was statistically significant ( t=4.41, P<0.001). Multivariate logistic regression analysis showed that NLR and latency period were independent risk factors for tetanus severity (odds ratio ( OR)=2.359, 95% confidence interval ( CI) 1.415 to 3.934, P=0.001 and OR=0.748, 95% CI 0.599 to 0.936, P=0.011, respectively). In tetanus patients, the NLR level was positively correlated with Ablett grade ( r=0.644, P<0.001). The ROC curve showed that NLR had good predictive value for adult severe tetanus at a cut-off value of 2.471 (area under the curve (AUC)=0.787), with the sensitivity and specificity of 87.1% and 61.8%, respectively. When combining NLR with latency period (cut-off value of 7.5 d), predictive efficiency was further improved (AUC=0.832) with the sensitivity of 87.1% and specificity of 67.6%( Z=3.43, P<0.001). Conclusions:NLR has a good predictive value for adult severe tetanus, and the predictive efficiency is further improved when combined with latency period.