Obesity and early sepsis-associated acute respiratory distress syndrome: A prospective multicenter study

The role of obesity in sepsis-associated acute respiratory distress syndrome (SA-ARDS) remains uncertain, particularly amid evolving diagnostic criteria. We aimed to assess whether obesity differentially influences SA-ARDS incidence and mortality under the Berlin definition versus an expanded framework incorporating high-flow nasal cannula (HFNC).

This prospective multicenter cohort study included 1799 adults with sepsis 3.0 from three ICUs. SA-ARDS was diagnosed using (1) Berlin criteria and (2) a new definition integrating HFNC. The primary outcome was incidence of SA-ARDS. Secondary outcomes included 28- and 90-day mortality in SA-ARDS patients.

Obesity was independently associated with elevated SA-ARDS incidence under the new definition (adjusted OR 5.61, 95% CI 4.56-6.92; AUC = 0.700), with even higher risk in ARDS patients under Berlin criteria (OR 6.66, 95% CI 5.01-8.91) and HFNC recipients (OR 5.77, 95% CI 3.85-8.85). These associations remained robust in PSM and IPW analyses. However, in ARDS patients of the new definition (including HFNC patients), no survival differences were observed across BMI categories. However, under the Berlin definition, obesity patients had significantly lower 90-day mortality than underweight and normal-weight patients, particularly in the elderly and those with prolonged hospital stays (P < 0.05).

Obesity independently increased SA-ARDS risk across both diagnostic frameworks. However, the mortality benefit (Berlin definition) was absent when using the expanded criteria incorporating HFNC. This indicates obesity drives susceptibility but confers no universal survival advantage in new ARDS cohorts.