Research led by the University of Pittsburgh shows not accounting for race when calculating kidney function before starting anticancer treatments could lead to Black patients being unnecessarily excluded.
The team, led by Thomas Nolin, associate professor of pharmacy and therapeutics at Pitt’s School of Pharmacy, carried out the assessment because the necessity of the addition of race into the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation to calculate function has been recently called into question.
Estimated glomerular filtration rate (eGFR), a measure of kidney function, is known to vary to different degrees depending on a person’s ethnicity. Generally, black patients are known to have an approximately 16% higher eGFR for a given serum creatinine concentration, sex, and age, versus white patients.
This is important for cancer patients as the result of the CKD-EPI equation is used to calculate eligibility for a variety of different anti-cancer drugs. By excluding race from the equation Nolin and team found that many black patients would have a lower eGFR score and would therefore be less likely to receive cancer treatment. As cancer rates are higher in the black than the white population, this could just exacerbate current health disparities.
“Ultimately, we hope our results raise awareness of the issue, and we urge doctors to use appropriate clinical judgement and to think logically about weighing the risks and benefits of cancer drugs in the context of the patient’s kidney function,” said Nolin in a press statement.
The researchers carried out a retrospective analysis of National Cancer Institute Phase I clinical trial participants enrolled in trials between 1995 and 2010. Overall, data from 340 black patients (172 men and 168 women) was included in the study, which is published in the journal The Lancet: Oncology. When the CKD-EPI equation was used with and without an adjustment for race, the researchers found that up to 18% of the cohort would have had different treatment recommendations if race was excluded.
For example, the number of black people ineligible to receive chemotherapy medication called cisplatin or bleomycin increased by 72% and 163%, respectively, if race wasn’t considered.
“This finding underscores the crucial impact that the choice of GFR-estimating equation, including whether or not to include race in the calculation, has on drug eligibility and dosing in Black patients with cancer,” write the authors.
“Black patients experience disparities in both cancer incidence and mortality, and are therefore especially susceptible to disease undertreatment. Removal of race from GFR-estimating equations could lead to higher rates of anticancer drug exclusion, dose reduction, and disease undertreatment in Black patients with cancer, and thus could adversely affect survival outcomes.”
A recent joint task force established by the National Kidney Foundation and the American Society of Nephrology proposed replacing eGFR equations that include race with other options that do not to prevent race being used as a biological determinant of disease.
Alternative equations excluding race have been developed, but not rolled out yet and it is unclear when they could go into widespread use.
“This study underscores the need for careful clinical judgement and a patient-centered approach in interpreting and comparing kidney function estimates from different GFR-estimating equations, including a thorough understanding of the limitations of each equation, especially when selecting and dosing anticancer drugs with a narrow therapeutic index,” concludes the team.