Serum Interleukin-6 as an Early Indicator of Trauma Complications

Trauma is a major global health issue, associated with high mortality and complications like inapparent hypoxia, fat embolism syndrome (FES), sepsis, and multiple organ dysfunction syndrome (MODS). Early identification of high-risk patients is crucial but challenging. Serum interleukin-6 (IL-6), a key inflammatory cytokine, has shown potential as a biomarker for predicting adverse outcomes in trauma. IL-6 levels typically increase rapidly following trauma, peaking within 12 to 24 hours. Despite its potential role, there is limited research on the effectiveness of IL-6 as an early marker for trauma-related complications. This study aims to assess whether monitoring serum IL-6 levels at specific intervals after trauma can aid in early risk assessment and predict the development of these complications.

This prospective observational cohort study at North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences (NEIGRIHMS) included 119 trauma patients aged 19-65 years, admitted within 12 hours of injury. Venous blood samples (5 mL each) were collected at 12 and 24 hours for IL-6 and C-reactive protein (CRP) analysis. Injury severity score (ISS) was assessed for all the patients upon arrival to the emergency department at NEIGRIHMS and was categorized as mild, moderate, severe, and very severe. Inapparent hypoxia, FES, sepsis, and MODS were assessed using pulse oximetry, Gurd's criteria, quick sequential organ failure assessment (qSOFA) score, and Marshall's multiple organ dysfunction score, respectively.

Among the participants, 21.85% developed complications; primarily inapparent hypoxia. Serum IL-6 levels were significantly elevated in individuals with complications at both 12 hours (p < 0.001) and 24 hours (p < 0.001) post-trauma. At the 12-hour mark, serum IL-6 demonstrated a sensitivity of 92.3% and a specificity of 78.5%, with a cut-off value of 37.26 pg/mL. By 24 hours, the sensitivity increased to 96.2% and the specificity to 87.1%, with a cut-off value of 55.08 pg/mL. Patients with MODS had the highest IL-6 levels, with medians of 270.87 pg/mL at 12 hours and 826.10 pg/mL at 24 hours. A strong correlation was observed between serum IL-6 at 24 hours and the ISS (r_s = 0.725, p < 0.001). At 12 hours, there was a moderate correlation between serum IL-6 and CRP (r_s = 0.488, p < 0.001). By 24 hours, this correlation strengthened to a strong level (r_s = 0.749, p < 0.001).

The significant association of serum IL-6 levels with both ISS and CRP highlights its potential role in assessing trauma severity. The high sensitivity and specificity of IL-6 at the 24-hour make it a valuable biomarker for the early detection of trauma-related complications.