Anti-Black racism in Canadian clinical tools

Defining race correction

The process of adjusting Black people’s diagnostic tests is called race correction, and is applied to a range of tests, including but not limited to those used to assess kidney, lung, and cognitive function.^1-3 In these cases, the supposed correction that clinicians apply to a Black person’s tests makes the person seem healthier than indicated through unadjusted diagnostics and diverts health care resources away from Black patients. This race correction (also termed race “norming,” “modifier,” or “adjustment”) is systematized, that is, embedded in a diagnostic process generally in the form of an equation or algorithm. With only a few exceptions, it is applied to Black people.¹ Race correction is rarely disclosed to patients, is applied without informed consent, and violates both the physician’s duty of care and the patient’s human rights. It prevents Black people from accessing the best clinical practices, delaying or preventing appropriate diagnosis and treatment, and contributes to chronic illness, suffering, and premature death at the population level.^4-6

Race correction and estimating kidney function

The creatinine-based estimated glomerular filtration rate (eGFR) test is commonly used to estimate kidney function. In Canada, renal impairment is often managed in primary care.^7,8 For close to 20 years, the 2 equations used to calculate creatinine-based eGFR in Canada have applied a correction for people classified as Black or of African descent.⁹ This correction adjusts the eGFR values of Black people upwards by 16% to 18%, which falsely portrays a patient’s kidney function as better than it is in the unadjusted laboratory results.¹⁰ This impacts decisions about diagnosis, prescribing, dosing, referral, and treatment. This has had concrete and devastating effects. A recent study in the United States (US) looked at eGFR results for a sample of Black people between 2015 and 2018.⁶ Researchers found that, if race correction had been removed, 3 million more Black people would have moved to the more severe stage III classification of chronic kidney disease (CKD), thus qualifying for additional care; 300,000 more Black people would have qualified for a referral to a nephrologist; and 31,000 more Black people would have been eligible for transplant evaluation and waitlist inclusion.⁶ Another US study examined eGFR results for a sample of Black people between 1999 and 2018 and found that, if race correction had been removed, almost 1 million additional Black people in the general US population would have been diagnosed with CKD.¹¹ In addition, given that physicians use eGFR to help determine medication indication and dosing, this has implications for patient treatment in primary care and across specialties.⁹

In 2021, the National Kidney Foundation (NKF) and American Society of Nephrology (ASN) formed a task force on reassessing the inclusion of race in diagnosing kidney disease. The task force provided a revised process for estimating kidney function in the US,¹² recommending that eGFR measurement use 2 biomarkers, creatinine and cystatin C, as best clinical practice, stating that, “combining filtration markers (creatinine and cystatin C) is more accurate and would support better clinical decisions than either marker alone.”¹² Where cystatin C tests are not yet widely available, the task force recommends a new creatinine-based eGFR measurement without a race correction, the CKD epidemiology collaboration creatinine equation refit (CKD-EPI 2021).¹²

In April 2024, the Ontario Renal Network (ORN) recommended that all laboratories in Ontario use the NKF-ASN task force’s second-line option,¹² the CKD-EPI 2021. This should be a time-limited, interim measure with a specified end date until an eGFR that uses both creatinine and cystatin C can be made available to all patients and routinely ordered by family physicians, as recommended, in the context of a patient’s clinical presentation and history.¹² These actions must be accompanied by a systematic and transparent process, one that follows best practices as outlined in the literature exploring the de-adoption of harmful practices in health care.^13,14

The ORN’s announcement, which came after years of work by Black experts, patients, and communities in Canada and the US, represents a crucial moment for Black people and communities in Ontario, and could inform actions in other provinces. It is essential that conversations about race corrections applied to eGFR and other diagnostics do not end at description—and there is precious little of even this—but also centre on responsible and systematic de-adoption. As a first step, to help address the health care inequity generated by this race correction, clinicians can begin by informing all Black people who may have been affected to re-assess their kidney function and ensure they are receiving appropriate and timely care.¹⁵ However, clinicians should not assume that all laboratories are using the CKD-EPI 2021. Some laboratories have announced in the past they are using the CKD-EPI 2021, but Black patients received eGFR values with the instruction to the clinician to continue the practice of race correction. In keeping with the duty to care, along with the patient’s right to receive non-discriminatory health care, clinicians are responsible for ensuring the diagnostics received by their Black patients are accurate and use the most recent standard of care.

Beyond kidney function

Similar consequences of race correction are found across specialties and diseases—including cardiovascular health, obstetrics and gynecology, and pediatrics—with wide-ranging and devastating consequences, including disparate outcomes in mortality, morbidity, disability, quality of life, and wealth.¹ For example, a US study examining the impact of race correction applied to lung function tests found that removing race correction could result in an additional 428,000 Black people being diagnosed with moderate-to-severe chronic obstructive pulmonary disease and an additional 638,000 Black people eligible for greater compensation for work-related exposure to dust or fumes.^4,16 In 2021, Black football players in the US who were underdiagnosed with ailments related to traumatic brain injuries successfully sued the National Football League over race norming and were included in a billion-dollar settlement.¹⁷