The predictive value of serum procalcitonin level as a prognostic marker for outcomes in out-of-hospital cardiac arrest patients

Background: Patients who have successful return of spontaneous circulation after cardiac arrest may experience post-cardiac arrest syndrome. Procalcitonin can be used to assess the severity of post-cardiac arrest syndrome. The association between procalcitonin and outcomes in Asian patients with post-cardiac arrest syndrome has not been extensively studied. Objective: This study aimed to investigate the predictive value of serum procalcitonin level in the prognosis of patients hospitalized after out-of-hospital cardiac arrest. Methods: A retrospective observational study using the multicenter Korean Cardiac Arrest Research Consortium registry between October 2015 and June 2018 was performed. Serum procalcitonin level at the early phase of hospital presentation was obtained from the patients hospitalized after out-of-hospital cardiac arrest. In-hospital mortality and neurologic outcomes at hospital discharge were estimated. The relationship between serum procalcitonin level and in-hospital mortality and neurologic outcomes of patients was analyzed. Results: A total of 254 patients hospitalized after out-of-hospital cardiac arrest were included. Serum procalcitonin level was significantly elevated in non-survivors compared to survivors (0.17 (0.05-0.18) ng/dL vs. 0.10 (0.05-0.39) ng/dL,p = 0.017, respectively). In addition, serum procalcitonin level was significantly elevated in patients with unfavorable outcomes at hospital discharge compared to those with favorable outcomes (0.16 (0.06-1.10) ng/dL vs. 0.07 (0.04-0.22) ng/dL,p < 0.001, respectively). However, serum procalcitonin level had a weak predictive value for in-hospital mortality (area under the receiver operating characteristic curve: 0.587, 95% confidence interval: 0.517-0.657,p = 0.017, cut-off = 0.12 ng/dL, specificity = 57.4%) and unfavorable outcomes (area under the receiver operating characteristic curve: 0.646, 95% confidence interval: 0.571-0.721,p < 0.001, cut-off = 0.11 ng/dL, specificity = 62.3%). Conclusion: Elevated serum procalcitonin level in patients hospitalized after out-of-hospital cardiac arrest at the early phase of hospital presentation is associated with poor outcomes. However, serum procalcitonin level had weak diagnostic accuracy for predicting in-hospital mortality and unfavorable outcomes.