Racial Disparities in Pulse Oximetry, in COVID-19 and ICU Settings

Abstract

Objectives background: This study aimed to assess the impact of race on pulse oximetry reliability, taking into account Spo₂ ranges, COVID-19 diagnosis, and ICU admission.

Design: Retrospective cohort study covering admissions from January 2020 to April 2024.

Setting: National COVID Cohort Collaborative (N3C) database, consisting of electronic health records from 80 U.S. institutions.

Patients/subjects: Patients were selected from the N3C database based on the availability of data on self-identified race and both pulse oximetry estimated Spo₂ and Sao₂. Subgroups included patients in ICU and non-ICU settings, with or without a diagnosis of COVID-19 disease.

Interventions: None.

Measurements and main results: The agreement between Spo₂ and Sao₂ was assessed across racial groups (American Indian or Alaska Native, Asian, Black, Hispanic or Latino, Pacific Islander, and White). Each patient's initial Sao₂ measurement was matched with the closest Spo₂ values recorded within the preceding 10-minute time frame. The risk of hidden hypoxemia (Spo₂ ≥ 88% but Sao₂ < 88%) was determined for various Spo₂ ranges, races, and clinical scenarios. We used a generalized logistic mixed-effects model to evaluate the impact of relevant variables, such as COVID-19, ICU admission, age, sex, race, and Spo₂, on the risk of hidden hypoxemia, while accounting for the random effects within each hospital. A total of 80,541 patients were included, consisting of 596 American Indian or Alaska Native, 2,729 Asian, 11,889 Black, 13,154 Hispanic or Latino, 221 Pacific Islander, and 51,952 White individuals. Discrepancies between Spo₂ and Sao₂ were observed across all racial groups, with the most pronounced bias in Black patients. Hidden hypoxemia rates were higher in Black patients across all Spo₂ subgroups, for all clinical scenarios. The odds of hidden hypoxemia were higher for Black and Hispanic or Latino patients and for those with COVID-19 disease.

Conclusions: Race significantly impacts pulse oximetry reliability. Not only Black and Hispanic or Latino patients were at higher risk for hidden hypoxemia, but also those admitted with a COVID-19 diagnosis. Future in-depth explorations into the underlying causes and potential solutions are needed.

Figure 1.

This plot illustrates the odds ratios for hidden hypoxemia with 95% CIs obtained from the generalized logistic mixed-effects analysis for predictors Asian vs. White, Black vs. White, Hispanic or Latino vs. White, male vs. female, COVID-19 vs. non-COVID-19, ICU vs. non-ICU, age and Spo₂. Predictors below the horizontal dashed line are continuous, above the dashed line categorical. Odds ratios > 1 indicate a positive independent association between predictor and outcome. The asterisks (*) denote the statistical significance of the predictor variables on the outcome, *p < 0.05; ***p < 0.001.