Serum IL-27 as a potential biomarker for intestinal injury severity and 28-day mortality prediction in critically ill patients with acute gastrointestinal injury: a retrospective cohort study

<title>Abstract</title> <p> <bold>Background</bold> Acute gastrointestinal injury (AGI) is a frequent complication in critically ill patients and is associated with increased morbidity and mortality. However, reliable biomarkers for early assessment of intestinal injury severity and prognosis remain limited. Interleukin-27 (IL-27), an immunoregulatory cytokine involved in inflammatory responses, has been reported to be associated with disease severity in critically ill conditions, but its clinical significance in patients with AGI remains unclear. This study aimed to investigate the association between serum IL-27 levels, intestinal injury biomarkers, and clinical outcomes in critically ill patients with AGI. <bold>Methods</bold> This retrospective single-center cohort study included 75 critically ill patients with AGI admitted to the intensive care unit of Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University between October 2023 and March 2024. Patients were categorized into survivor and non-survivor groups according to 28-day outcomes. Serum IL-27, intestinal fatty acid-binding protein (IFABP), and diamine oxidase (DAO) levels were measured within 24 h after ICU admission. Correlation analyses, logistic regression analyses, receiver operating characteristic (ROC) curve analyses, and Kaplan–Meier survival analyses were performed to evaluate the prognostic value of IL-27. <bold>Results</bold> Serum IL-27 concentrations were significantly higher in non-survivors than in survivors (230.86±107.27 vs. 153.41±72.59 pg/mL, P &lt; 0.001). Serum IL-27 levels were positively correlated with IFABP and DAO concentrations (r = 0.541 and r = 0.483, respectively; both P &lt; 0.05). Furthermore, IL-27 concentrations increased progressively with increasing AGI severity. Multivariable logistic regression analysis demonstrated that higher serum IL-27 was independently associated with lower odds of 28-day survival after adjustment for age and sex. ROC curve analysis showed that IL-27 had superior predictive performance for mortality (AUC = 0.885, sensitivity = 71.4%, specificity = 95.7%), with an optimal cutoff value of 235.81 pg/mL. Kaplan–Meier analysis revealed significantly lower 28-day survival among patients with IL-27 levels above this cutoff value (P = 0.02). <bold>Conclusions</bold> Serum IL-27 is associated with intestinal injury severity and adverse clinical outcomes in critically ill patients with AGI. IL-27 may serve as a promising biomarker for early risk stratification and mortality prediction in patients with acute gastrointestinal injury. </p>