Impact of body mass index on mortality outcomes in intensive care patients with Staphylococcus aureus sepsis: A retrospective analysis

Abstract

Background Evidence associating body mass index (BMI) with the prognosis of Staphylococcus aureus sepsis remains scarce. Objective To explore the association between BMI and clinical outcomes in intensive care units patients with Staphylococcus aureus sepsis. Methods A retrospective analysis of patients with Staphylococcus aureus sepsis was conducted using the MIMIC-IV database from the Critical Care Medicine Information. Data were collected within the first 24 hours of intensive care units admission. The primary endpoint was 28-day mortality. The association between BMI and 28-day all-cause mortality was assessed using multivariable logistic regression, subgroup analyses, restricted cubic spline curves and Kaplan-Meier survival analysis. Results The study included 2,295 patients with an average age of 63.5 (16.1) years, 60.2% of whom were male. Multivariate analysis revealed that each 1 kg/m2 increase in BMI was linked to a 2.8% decrease in the risk of 28-day mortality (adjusted OR = 0.972, 95% CI: 0.955–0.990, P = 0.002). Patients in the medium and high BMI categories had significantly lower risks of 28-day mortality compared to those in the low BMI group (OR [95% CI] 0.650 [0.474–0.891]; OR [95% CI] 0.516 [0.378–0.705]; P trend < 0.0001). The RCS model showed a non-linear association between BMI and 28-day mortality (P = 0.014). Kaplan-Meier analysis showed that patients with elevated BMI had lower 28-day mortality (P < 0.0001). Notably, significant interactions between AKI and SOFA with BMI were observed (P<0.05). Conclusion Increased BMI is associated with a reduced risk of 28-day all-cause mortality in patients with Staphylococcus aureus sepsis.