Female, Black, and Low-Income Patients Less Likely to Receive ECMO

Female patients, patients with Medicaid, and those who live in the lowest income neighborhoods are far less likely to receive extracorporeal membrane oxygenation (ECMO), researchers reported in the Annals of the American Thoracic Society.

“ECMO is one of the most advanced, complex, resource intensive, and expensive interventions available to critically ill patients with respiratory and/or cardiovascular failure,” which makes optimal patient selection critical, study authors noted. In the face of multiple previous studies indicating inequities in critical care treatment, researchers conducted a population study to assess the effects of sex, insurance status, and neighborhood income on patient selection for ECMO in the US. The researchers hypothesized that if ECMO patient selection was equitable, the percentage of those receiving ECMO and mechanical ventilation (MV) would be similar.

The investigators conducted a retrospective study analyzing data from the Utilizing the Nationwide Readmissions Database (NRD) from 2016 to 2019 for adult patients (aged >18 years). The primary outcome was receiving ECMO, and the primary exposures were patient sex, primary insurance, and median income quartile for the zip code in which the patient lived.

A total of 2,170,752 cases of mechanical ventilation (MV) with 18,725 cases of ECMO were identified. The patients who received ECMO were younger (mean age, 54.1 years) than those who received MV only (mean age, 62.6 years). Female patients represented 36.1% of those receiving ECMO vs 44.5% of patients treated with MV only. Female patients’ odds of receiving ECMO compared with male patients was 0.73 (adjusted odds ratio [aOR]; 95% CI, 0.70-0.75).

Patients with Medicare as their primary insurance represented 36.5% of those receiving ECMO vs 57.7% of those treated only with MV. Overall, patients receiving ECMO had higher rates of private insurance vs those receiving MV (38.1% vs 17.4%). Patients with Medicaid (aOR, 0.55; 95% CI, 0.52-0.57) and Medicare (aOR, 0.50; 95% CI, 0.48-0.52) had reduced odds of receiving ECMO compared with patients who had private insurance.

Patients living in the lowest income neighborhoods represented 24.5% of those receiving ECMO vs 32.7% of those treated with MV only. Additionally, patients receiving EMCO were likely to live in the highest vs lowest income neighborhoods (25.1% vs 17.3%, respectively). The adjusted odds of patients in the lowest income neighborhoods receiving ECMO compared to those living in the highest income neighborhoods was 0.63 (95% CI, 0.60-0.67).

In sensitivity analyses with use of inverse probability of treatment weight to reduce differences in exposure groups, similar differences were observed in patient selection. Compared with male patients who lived in the highest income neighborhoods, female patients who lived in lower income quartile neighborhoods had lower odds of receiving ECMO (aOR, 0.50; 95% CI, 0.46-0.53). In the State Inpatient Databases (SID), patients identified as Black were less likely to receive ECMO vs those who identified as White (aOR, 0.72; 95% CI, 0.65-0.79), but no differences occurred based on ethnicity.

Limitations include the potential for residual confounding and the potential for misclassification bias, given that NRD is an administrative database dependent on billing codes. Also, the SID analysis found racial disparities in ECMO patient selection, but the investigators were unable to differentiate between hospital-assigned race and self-identified race.

“This study highlights multiple demographic disparities in adult patient selection for ECMO that might be driven by lack of access, restrictive transfer policies, patient preference, and implicit provider bias,” noted the study authors.