Clinical Impact of Removing Race from Estimates of Kidney Function

Clinical Impact of Removing Race from Estimates of Kidney Function
Paige Behrend, PharmD, Park Nicollet Health Services

Background: Race-based adjustments are still present in various clinical algorithms used for disease risk assessment and therapeutic guidance, despite a lack of evidence that race is a reliable predictor of genetic difference. Many medical centers across the U.S. have begun the process of removing race from these clinical tools and algorithms due to mounting concern that race-based medicine may be perpetuating disparities and biases in healthcare. For example, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and the Modification of Diet in Renal Disease (MDRD) equations for estimating kidney function include a race-based adjustment to account for hypothetical higher serum creatinine concentrations in patients that identify as Black. When used within these equations, the adjustment suggests a higher estimated kidney function that may not accurately represent the patient’s true renal function. A recent study by Diao et. al aims to quantify the impact of removing race from kidney function estimators on CKD diagnosis, CKD stage reclassifications, nephrologist referrals, and more.

Evidence and Discussion: The study utilized laboratory measurements and demographics from adult National Health and Nutrition Examination Survey (NHANES) participants from 2001 to 2018. In total, the study cohort included 9,522 non-Hispanic Black adults with a median age of 45 years. The CKD-EPI equation was utilized to calculate estimated glomerular filtration rate (eGFR) with and without the race coefficient. After removal of the race coefficient, the median eGFR decreased from 102.9 mL/min/1.73m2 to 88.8 mL/min/1.73m2. Based on this data, removing race from the CKD-EPI equation may increase the prevalence of CKD among Black adults in the U.S. from 14.9% to 18.4%. Additionally, 29.1% of Black adults with pre-existing CKD may be reclassified to a more severe stage. This overestimation of eGFR may have significant pharmacological implications, such as necessitating a dose adjustment for metformin or the emergence of an indication for an angiotensin-converting enzyme inhibitor to protect renal function and delay CKD progression.

In addition to the implications on CKD diagnosis and staging, access to kidney care and services is impacted by the overestimation of eGFR in Black adult patients. Computing eGFR without race would allow 0.36% of Black adults to receive kidney disease education instead of 0.22%. Currently Medicare covers medical nutrition therapy for 5% of Black adults, but this increases to 5.5% with removal of race coefficient. Increasing access to both kidney disease education and medical nutrition therapy can help delay CKD progression and help improve overall health outcomes among Black patients. Additionally, computing eGFR without race may increase the proportion of Black adults qualified for kidney transplant by 0.05%, which equates to an additional eight patients eligible for transplant among the 9,522 non-Hispanic Black adults included in the NHANES sample population.

Clinical Impact: Removal of race-based adjustments from kidney function estimators may increase CKD diagnoses and severity of CKD staging within adult Black patients, as the inclusion of race coefficients can result in false estimates of actual kidney function. Overestimation of eGFRs in adult Black patients perpetuates racial healthcare inequalities by delaying access to nephrologists, medical nutrition therapy, kidney disease education, and kidney transplantation.

 

References:

  1. Diao JA, Wu GJ, Taylor HA, et al. Clinical implications of removing race from estimates of kidney function. JAMA. 2021;325(2):184–186. doi:10.1001/jama.2020.22124
  2. Vyas DA, Eisenstein LG, Jones DS. Hidden in Plain Sight - Reconsidering the use of race correction in clinical algorithms. N Engl J Med. 2020 Aug 27;383(9):874-882. doi: 10.1056/NEJMms2004740.