Obesity Increases Risk of Sepsis-Associated ARDS, suggests study

A new study published in the journal of Respiratory Medicine showed that in sepsis patients, obesity is a significant and independent risk factor for acute respiratory distress syndrome (ARDS).

Obesity is an increasing worldwide health problem and a major risk factor for poor outcomes in critically sick individuals. Sepsis is a leading cause of morbidity and death, and it can result in ARDS, which is defined by extensive pulmonary inflammation, increased alveolar-capillary permeability, and severe hypoxemia. Obesity can affect the development and clinical course of sepsis-associated ARDS by a variety of pathways, including persistent low-grade systemic inflammation, altered immunological responses, poor respiratory mechanics, endothelial dysfunction, and metabolic abnormalities. Excess adiposity may lower functional reserve capacity and lung compliance, increasing the risk of respiratory worsening after a severe illness.

Furthermore, obesity-related inflammatory mediators and adipokines may exacerbate the pulmonary response to sepsis, contributing to alveolar damage. However, the link between obesity and the early onset of sepsis-associated ARDS is still unclear, with previous research revealing varying relationships. Understanding whether obesity increases early ARDS risk in sepsis patients may help with risk assessment, prompt respiratory care, and tailored therapy methods. Thus, this study looked at the relationship between obesity and early sepsis-associated ARDS.

1799 people with sepsis 3.0 from three intensive care units participated in this prospective multicenter cohort research. The Berlin criteria and a revised definition incorporating HFNC were used to diagnose SA-ARDS. The incidence of SA-ARDS was the main result. 28- and 90-day death rates among SA-ARDS patients were secondary outcomes.

Under the revised definition, obesity was independently linked to increased SA-ARDS incidence (adjusted OR 5.61, 95% CI 4.56-6.92; AUC = 0.700).The risk was much higher in ARDS patients who met the Berlin criteria (OR 6.66, 95% CI 5.01-8.91) and HFNC recipients (OR 5.77, 95% CI 3.85-8.85). These correlations held up well in IPW and PSM analyzes. However, no differences in survival were found across BMI categories in ARDS patients of the current classification (including HFNC patients).

However, according to the Berlin criteria, patients who were obese had a considerably lower 90-day death rate than those who were underweight or normal weight, especially those who were older and had longer hospital stays (P<0.05). Overall, obesity independently enhanced the incidence of SA-ARDS in both diagnostic paradigms. 

Reference:

Zhao, L., Li, Y., Lin, X., Cui, Q., Liu, J., Yang, F., Wang, Y., Wang, J., Liu, Y., Shi, X., Cao, D., Li, J., Su, F., Zhang, H., & Xie, K. (2026). Obesity and early sepsis-associated acute respiratory distress syndrome: A prospective multicenter study. Respiratory Medicine, 261(109007), 109007. https://doi.org/10.1016/j.rmed.2026.109007