ECMO Therapy Out of Reach for Multiple Socioeconomic Groups

Socioeconomic disparities made certain groups on mechanical ventilation less likely to receive extracorporeal membrane oxygenation (ECMO) treatment in the years before the pandemic, a Nationwide Readmissions Database study found.

Women were a relative 27% less likely to receive ECMO than their male counterparts (adjusted OR 0.73, 95% CI 0.70-0.75), while patients on Medicaid were nearly half as likely to be treated with the more advanced treatment for severe respiratory failure than those with private insurance (adjusted OR 0.55 95% CI 0.52-0.57), reported Anuj Mehta, MD, of the University of Colorado School of Medicine in Denver, and colleagues.

Moreover, individuals living in the lowest-income neighborhoods were 37% less likely to get ECMO than those in higher income neighborhoods (adjusted OR 0.63, 95% CI 0.60-0.67), according to the retrospective cohort study published in the Annals of the American Thoracic Society.

"We speculate that several factors contribute to the differential utilization in ECMO by gender, insurance, and neighborhood income that was observed in this study: reduced access, restrictive transfer practices, patient preferences and implicit provider bias," the group wrote.

Disparities persisted when intersectionality was factored into the results of the study. For example, female patients still had lower chances of receiving ECMO, regardless of income status. According to the researchers, it's access to care that perpetuates a large share of the various disparities present.

ECMO is an advanced, resource-intensive treatment that can simulate the function of the heart, lungs, or both in critically ill patients. ECMO utilization has been steadily rising, with significant increases seen from 2007, where there were approximately 352 ECMO hospitalizations in the U.S., to 2012, where there were 2,715.

ECMO usage was prominent during the pandemic, often as a "last resort" for patients in need of breathing support. In one study of nearly 60,000 COVID patients, 4,044 received ECMO treatment, with a 39% mortality rate.

But most hospitals are still not ECMO-capable, with only about half of patients requiring mechanical ventilation admitted to hospitals equipped with the advanced form of life support.

"ECMO-capable hospitals tend to be clustered in major cities and far from rural areas (fewer than 15 cases of ECMO in rural hospitals in this study), and few safety-net hospitals have ECMO capabilities," the researchers explained.

In the current study, an analysis using several state inpatient databases found that Black patients were also less likely to be treated with ECMO than their white counterparts (adjusted OR 0.72, 95% CI 0.65-0.79), but the researchers noted that "patients with Medicaid, those living in lower income neighborhoods, and patients identified as Black are more likely to utilize safety-net hospitals. Therefore, some of the observed disparity may be less related to specific-patient selection patterns and more related to ECMO availability in certain types of hospitals and in certain geographic regions."

Mehta and colleagues said that addressing the gaps in access to ECMO treatment will lead to a better understanding of these disparities.

"The goal is to really get people thinking about where some disparities within critical care might live," said Mehta in a press release from the NIH, which helped fund the study. "The next step is to think about how we can investigate those disparities with better data and better sources, which supports the long-term goal of ensuring equitable care."

The study was based on 2016-2019 data from the Nationwide Readmissions Database, with treatment confirmed through billing codes.

A total of 2,170,752 patients received mechanical ventilation only in the study, while 18,725 were treated with ECMO.

Women made up 36% of the patients who received ECMO versus 64% of men. Women also made up a smaller proportion of patients who only received mechanical ventilation, but to a lesser degree (45% vs 55%).

When it came to insurance type in the ECMO group, most patients had either private insurance (38%) or were Medicare beneficiaries (37%), followed by Medicaid (18%) and other or no insurance (7%). In the mechanical ventilation-only group, most had Medicare (58%), followed by Medicaid and private insurance (17% each) and other or no insurance (8%).

People living in a high-income neighborhood made up 25.1% of the ECMO group in comparison to 17.3% of mechanical ventilation-only group.

The researchers noted that ECMO patients were often younger than patients who only received mechanical ventilation (54 vs 63 years old), were more likely to have chronic heart failure (38% vs 27%), and less likely to have chronic lung disease (19% vs 32%).

Among the limitations of this study are its inability to further break down ECMO populations by "at-risk" status, no differentiation between hospital-assigned and self-identified race demographics, and potential errors in billing code classification.

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