Diagnostic performance and optimal cut-off values of cardiac biomarkers for predicting cardiac injury in carbon monoxide poisoning

Abstract

Objective This study aimed to compare the diagnostic performance of cardiac biomarkers and to evaluate the optimal cut-off values for echocardiographic cardiac injury prediction in patients with carbon monoxide (CO) poisoning. Methods This retrospective observational cohort study included adult patients with acute CO poisoning. Patients who did not undergo transthoracic echocardiography, which was used to define patients with cardiac injury (ejection fraction <55%), were excluded. The area under the curve was used to evaluate diagnostic performance for cardiac injury prediction. Mann-Whitney U, chi-square, and Fisher exact tests were used to analyze data. Results After excluding the 27 patients who did not undergo echocardiography, 114 patients were included in the study. Fifteen (13.2%) patients had cardiac injury. The area under the curve values for the B-type natriuretic peptide, creatine kinase-myocardial band, and troponin I were 0.711 (95% confidence interval [CI], 0.527–0.895; P=0.011), 0.766 (95% CI, 0.607–0.926; P=0.001), and 0.801 (95% CI, 0.647–0.955; P<0.001), respectively, with optimal cut-off values of 330 pg/mL, 10.1 ng/mL, and 0.455 ng/mL, respectively. The sensitivity, specificity, and positive and negative predictive values of troponin I were 67%, 91%, 53%, and 95%, respectively. Conclusion Troponin I showed the best diagnostic performance for predicting cardiac injury in patients with CO poisoning. A cut-off value of 0.455 ng/mL appeared optimal for cardiac injury prediction. However, further studies on cardiac biomarkers and other diagnostic tools in CO poisoning are needed given the low sensitivity of troponin I.