The Prevalence and Clinical Significance of Low Procalcitonin Levels Among Patients With Severe Sepsis or Septic Shock in the Emergency Department

Background:The aims of this study were to evaluate the prevalence of low procalcitonin (PCT) levels among patients with severe sepsis or septic shock, and to investigate clinical characteristics and outcomes associated with low PCT levels.Methods:We analyzed data from the sepsis registry for patients with severe sepsis or septic shock in the emergency department. Based on a specific PCT cutoff value, patients were classified into two groups: a low PCT group, PCT <0.25ng/mL; and a high PCT group, PCT 0.25ng/mL. The primary endpoint was 28-day mortality. A multivariable logistic regression model was used to evaluate independent factors associated with low PCT and 28-day mortality.Results:A total of 1,212 patients were included. Of the eligible patients, 154 (12.7%) were assigned to the low PCT group, and 1,058 (87.3%) to the high PCT group. The 28-day mortality was 4.6% in the low PCT group and 13.5% in the high PCT group (P<0.01). The adjusted odds ratio of the low PCT group for 28-day mortality was 0.43 (95% CI 0.19-0.98; P=0.04). There was no trend of increasing mortality among higher PCT level patients. In a logistic regression model, factors associated with low PCT were pneumonia, lower C-reactive protein levels, lower lactate levels, the absence of bacteremia, and the absence of organ failure. Intra-abdominal infection and obesity were associated with high PCT.Conclusion:Initial low PCT levels were common among patients diagnosed with severe sepsis or septic shock in the emergency department, suggesting favorable outcomes. The prevalence of low PCT levels was significantly different according to obesity, the source of infection, C-reactive protein levels, lactate levels, bacteremia, and organ failure.