The primary goal of treating patients with carbon monoxide (CO) poisoning is preventing delayed neuropsychiatric sequelae (DNS). It is difficult to predict DNS because there is no precise diagnostic method in the early phase of CO poisoning. In this study, we aimed to investigate the optimal cut-off value for creatine kinase level to predict DNS.

This retrospective observational study included patients with CO poisoning visiting a single tertiary center from January to July 2018. They were divided into two groups according to the presence of DNS. We compared baseline characteristics with variables that could affect the presence of DNS. The optimal cut-off value of initial creatine kinase concentration for DNS was calculated. Additionally, multivariate analysis was performed to confirm whether creatine kinase could be an independent predictor of DNS.

Of the 138 patients, 12 patients developed DNS. Univariate analysis showed significant differences in the Glasgow Coma Scale, duration of exposure, laboratory tests, abnormal finding on MRI in acute phase, the number of hyperbaric oxygen therapy sessions, and duration of hospitalization. Receiver operating characteristic analyses of creatine kinase were performed (AUC = 0.92; 95% CI, 0.86–0.96) with a cut-off value of 1603 U/L; DNS was predicted with a sensitivity of 91.7% and specificity of 88.1%. In multivariate analysis, the adjusted odds ratio of creatine kinase was 51.516.

In patients with CO poisoning, initial creatine kinase concentrations of >1603 U/L can be used as an independent predictor of DNS.