Diagnostic Potential of Serum Interleukin-6 in Predicting Bacteremia in Adult Patients with Sepsis: A Prospective Observational Study

Background: This study aimed to assess the potential of serum interleukin-6 (IL-6) as a diagnostic marker in predicting bacteremia and to determine its association with severity and outcome among sepsis patients. Materials and methods: A prospective observational study was conducted, comprising a cohort of 118 patients admitted to the ICU with suspected sepsis from January 2019 to April 2020. Results: Among the 108 patients analyzed, 60 (55.6%) were bacteremic and 48 (44.4%) were nonbacteremic. Of 60 patients with bacteremia, 13 (21.6%) had sepsis and 47 (78.3%) had septic shock. In predicting bacteremia, the area under the curve (AUC) for IL-6 was 0.512 [95% CI, 0.400–0.623]. The AUC for IL-6 in differentiating sepsis from septic shock was 0.724 [95% CI, 0.625–0.823]. The sensitivity and specificity for predicting bacteremia for IL-6 were 66% and 67%, respectively (p < 0.001). Multivariate analysis revealed that C-reactive protein (CRP) (p = 0.04) and APACHE II score (p = 0.025) were significant predictors of bacteremia, whereas lactate (p = 0.04), and APACHE II score (p < 0.001) were significant predictors of sepsis severity. Patients with elevated levels of procalcitonin PCT (p = 0.024), APACHE II (p = 0.003), and SOFA (p = 0.002) scores had significantly higher mortality rates. Conclusion: C-reactive protein and APACHE II score, lactate and APACHE II score, and PCT, SOFA, and APACHE II scores performed better in predicting bacteremia, sepsis severity, and clinical outcome, respectively compared with IL-6.