Inflammatory Burden Index as a predictor of mortality in septic patients: A retrospective study using the MIMIC-IV Database

Purpose Previous studies have identified the Inflammatory Burden Index (IBI) as a potential predictor of mortality risk in inflammatory diseases. However, its relationship with mortality rates specifically in septic patients has not been thoroughly investigated. This study aimed to explore the association between IBI and mortality risk in patients with sepsis. Patients and methods: We sourced clinical records of 1,828 septic patients from the MIMIC-IV (3.0) dataset. The primary endpoint was mortality within 28 days, with secondary endpoints including mortality during ICU stays and throughout hospitalization. Patients were categorized into quartiles based on their LnIBI levels. Binary logistic regression was utilized to examine the independent influence of IBI on mortality outcomes, adjusting for confounders. Additionally, the association between IBI and these outcomes was explored using restricted cubic splines and Kaplan-Meier analysis. Results The study involved 1,828 septic patients, including 1,047 males. The all-cause mortality rates were 17.78% (325/1828) within 28 days, 17.34% (317/1828) during ICU stays, and 18.22% (333/1828) over the course of hospitalization. In the adjusted model, a positive correlation was found between Ln IBI and mortality at 28 days (OR 1.093[1.014, 1.179], P  = 0.021), during ICU stay (OR 1.106[1.025, 1.195], P  = 0.01), and throughout hospitalization (OR 1.1[1.022, 1.187], P  = 0.012). The analysis using restricted cubic splines showed a linear correlation between LnIBI and mortality risks. Kaplan-Meier plots revealed significantly lower survival rates for patients in the highest quartile of Ln IBI ( P  < 0.001). Conclusion Elevated IBI values are significantly linked with higher mortality risks within 28 days, during ICU, and throughout the hospitalization period in septic patients.