Abdominal Obesity and Short-term Mortality in Critically Ill Patients with Sepsis: A Retrospective Cohort Study Based on the MIMIC-IV Database

Abstract Purpose: Multiple studies have demonstrated an obesity paradox such that obese septic patients have a lower mortality rate and a relatively favorable prognosis. However, less is known on the association between abdominal obesity and short-term mortality in patients with sepsis. We conducted this study to determine whether the obesity-related survival benefit remains among abdominal obese patients.Methods: A retrospective cohort study was conducted using data derived from the Medical Information Mart for Intensive Care IV database. Septic patients (≥18 years) with or without abdominal obesity of first intensive care units (ICU) admission in the database were enrolled. The primary outcome was mortality within 28 days of ICU admission and multivariable logistic regression analyses were employed to assess any association between abdominal obesity and the outcome variable.Results: A total of 21534 patients were enrolled finally, the crude 28-day mortality benefit after ICU admission was not observed in patients with abdominal obesity (15.8% vs. 15.3%, p=0.32). In the extended multivariable logistic models, the odds ratio (OR) of abdominal obesity was significantly inversed after incorporating metabolic variables into the logistic model (OR range 1.094-2.872, p = 0.02). The subgroup analysis showed interaction effects in impaired fasting blood glucose/diabetes and metabolic syndrome subgroups (P = 0.001 and <0.001, respectively). In the subgroups of blood pressure, high-density lipoprotein cholesterol, and triglyceride level, no interaction was detected in the association between abdominal obesity and mortality. After propensity score matching, 6523 pairs of patients were selected. The mortality significantly higher in the abdominal obesity group (17.0% vs. 14.8%, p = 0.015). Notably, the non-abdominal obese patients were weaned off vasopressors and mechanical ventilation more quickly than those in the abdominal obesity group (vasopressor‑free days on day 28 of 27.0 vs. 26.8, p < 0.001; ventilation-free days on day 28 of 26.7 vs. 25.6, p < 0.001).Conclusion: Abdominal obesity was associated with increased risk of adjusted sepsis-related mortality within 28 days after ICU admission and was partially mediated through metabolic syndrome components.