Pulse oximeters have become commonplace during COVID-19, as a quick and affordable way for people to monitor their oxygen saturation in their own homes. In the healthcare setting, providers watch pulse oximeters for signs that their patient is in respiratory decline. However, studies in the 2000s investigated the efficacy of pulse oximeters on people with darker skin and showed that they often gave inaccurate readings for people of color [1,2]. Recently, correspondence published in the New England Journal of Medicine drew attention to the fact that Black patients were three times more likely than white patients to have occult hypoxemia that was missed by pulse oximeters, an example of racial disparities in medical diagnostic tools [3]. During a once-in-a-generation pandemic characterized by respiratory distress, this type of risk could result in avoidable morbidity and death for patients of color.
Pulse oximeters are not the only medical diagnostic tools that are related to racial disparities. Another article published in the New England Journal of Medicine investigated the racial bias implicit in clinical algorithms used to make medical decisions, focusing on cardiology, nephrology, and obstetrics. The AHA Get with the Guidelines Heart Failure Risk Score, which clinicians use to predict risk of death for hospitalized patients, adds three extra points for non-black patients, with no explanation why this adjustment exists [4]. Because black patients get lower scores than non-black patients, care is often directed away from black patients, resulting in increased morbidity and mortality [4]. Furthermore, surgeons use race as a factor in determining risk of death in surgery as a part of routine preoperative assessment [4]. Black patients have a significantly higher risk score than white patients, which often disqualifies them from getting needed procedures [4]. Similarly, nephrologists calculate estimated glomerular filtration rate (eGFR) as a measure of kidney function [4]. Just like with the AHA Heart Failure Risk Score, black patients are given a higher eGFR calculation, implying better kidney functioning when that may not be true [4]. This “race-correction” supposedly uses race as a proxy for muscularity and thus a higher average serum creatinine concentration [4], however, this explanation has since been called into question and there is an active petition from the Institute of Healing and Justice calling for eGFR to be updated.
Furthermore, the racial disparities in maternal mortality have been well-documented and partially stem from unnecessary C-sections being performed on black patients — physicians often use an algorithm called the VBAC as a tool to make decisions about whether patients who have previously undergone a C-section should have a vaginal birth, and the VBAC predicts worse outcomes for women of color [4]. Similar to eGFR, race is used as a proxy — for marital status and insurance type (which do have an effect on outcomes) — but this approach exacerbates the disparities that already exist in maternal mortality [4].
Clinicians use algorithms to make health decisions about their patients every day. Biased algorithms directly cause worse outcomes for patients of color. And while individual providers may not hold racial biases, these algorithms do underline a systemic problem of racism in healthcare. This new awareness of the racial disparities that are ingrained in the healthcare system through diagnostic tools and clinical algorithms will hopefully lead to systemic changes, improving patient outcomes across the board.
References
- Feiner JR, Severinghause JW, Bickler PE. Effects of Skin Pigmentation on Pulse Oximeter Accuracy at Low Saturation. Anesthesia & Analgesia, 2005; 102: 715-719. doi: 10.1097/00000542-200504000-00004
- Feiner JR, Severinghause JW, Bickler PE. Dark Skin Decreases the Accuracy of Pulse Oximeters at Low Oxygen Saturation: The Effects of Oximeter Probe Type and Gender. Anesthesia & Analgesia, 2007; 105(6): S18-S23. doi: 10.1213/01.ane.0000285988.35174.d9
- Sjoding MW, Dickson RP, Iwashyna TJ, Gay SE, Valley TS. Correspondence: Racial Bias in Pulse Oximetry Measurement. The New England Journal of Medicine, 2020; 383: 2477-2478. doi: 10.1056/NEJMc2029240
- Vyas DA, Einstein LG, Jones DS. Hidden in Plain Sight – Reconsidering the Use of Race Consideration in Clinical Algorithms. The New England Journal of Medicine, 2020; 383: 874-882. doi: 10.1056/NEJMms2004740
