Increased body mass index linked to greater short- and long-term survival in sepsis patients: A retrospective analysis of a large clinical database

•Overweight and obese patients had greater survival benefits at 30 days and 1year.•Underweight patients tended to have higher mortality risk.•Obese patients were shown to experience more aggressive treatments.•Obesity was associated with longer ventilation, ICU and hospitalization duration. We investigated the impact of obesity (proxied as body mass index (BMI)), on short- and long-term mortality in sepsis patients. We conducted a retrospective analysis with adult sepsis ICU patients in a US medical institution from 2001 to 2012 in the MIMIC-III database. The WHO BMI categories were used. Multivariate logistic regression assessed the relationships between BMI and 30-day and 1-year mortality. In total, 5563 patients were enrolled. Obese patients tended to be younger (P