Patients with obesity receiving ECMO for ARDS had lower mortality rates in ICU compared to non obese patients

The ECMObesity study, led by Dr. Darya Rudym and her team from New York University Langone Health, included nearly 800 patients who received ECMO for ARDS. The following key findings were reported:

• Among the patients who received ECMO for ARDS, 24.1% of those with obesity died, compared to 35.3% of those without obesity.
• In adjusted models, obesity was associated with a lower ICU mortality (odds ratio [OR] 0.63).
• Higher body mass index (BMI) was linked to decreased ICU mortality in multivariable regression (OR 0.97).
• When matching patients with obesity to those without, patients with obesity had a lower probability of ICU death (22.6% vs 35.2%).

The study challenges the conventional notion that obesity is a contraindication for ECMO. While obesity has often led to exclusion from ECMO trials, the study highlights the potential protective effects of obesity, commonly referred to as the "obesity paradox." Increased chest wall elastance and higher plateau airway pressures in patients with obesity may contribute to a protective effect, potentially lowering ventilator-induced lung injury.

Despite the study's findings, experts emphasize the need for further research to confirm and strengthen the results. Dr. Peter Pickkers, in an accompanying commentary, suggests that collider bias and selection bias could influence the study's outcomes. Nevertheless, the study underscores that obesity should not be a barrier to providing necessary care, especially when ECMO is required.

Dr. Rudym and her team hope that the study's results will guide treatment decisions for patients with obesity and ARDS. They advocate for the inclusion of patients with obesity in future clinical trials to enhance care for this patient population. The study is a significant step toward understanding the complex relationship between obesity, ECMO, and ARDS outcomes, offering potential insights into improved care for critically ill patients.

For the study, data from over 20 medical centers were analyzed, including 790 ARDS patients, of whom 320 had obesity. While further research is needed, the study opens doors to rethinking how obesity affects ICU outcomes, particularly in patients undergoing ECMO for ARDS.

Reference:

American Journal of Respiratory and Critical Care Medicine Rudym D, et al "Mortality in patients with obesity and ARDS receiving ECMO: the multicenter ECMObesity study" Am J Respir Crit Care Med 2023;  DOI: 10.1164/rccm.202212-2293OC