Abinaya Sridharan: June 7th, 2023
Introduction:
Chronic Kidney Disease involves a decreased or damaged function of one’s kidney. An easier way to figure out a patient’s kidney function is to use the “glomerular filtration rate (eGFR).” GFR has a scale and in meeting certain criteria can qualify a patient to get evaluated for chronic kidney disease, failure or even on the transplant waitlist. The GFR equation used to estimate your GFR score takes account sex, age, body type and race. In particular Black Americans are given a multiplier of 1.12 in the GFR equation, which has been proved to overestimate black patient’s kidney function. The EGFR has come under significant scrutiny in its validity and fairness of using race based adjustments in the equation.
Findings and Results:
The GFR equation which is referred to as the “MDRD” equation short for Modification of Diet in Renal Disease, its original equation which was created in 1999 took in account of race multiplying 1.212 for African Americans.
GFR (mL/min/1.73 m²) = 175 × (serum creatinine)^(-1.154) × (age)^(-0.203) × (0.742 if female) × (1.212 if African American)
The MDRD study revealed that Black patients had a higher measured glomerular filtration rate (GFR) compared to White patients, even when their creatinine concentration (a muscle breakdown product) was the same. However, the study failed to consider various factors that could contribute to the higher risk of chronic kidney disease (CKD) among Black patients. An analysis of the MDRD data indicated that Black participants had higher rates of diabetes, hypertension, and poverty, all of which are independent predictors of CKD. Yet, the study only justified the differences solely to variations in muscle mass between Black and White individuals, disregarding the more valid indicators.
Another limitation and concern of the MDRD study is that its main comparison was between Black and White patients yet they also included multiple patients from varying racial backgrounds, however exclusively separated them in two cohorts one for Blacks and the other for Non-Blacks, “for a purpose of race adjustment[1].” Further alienating black patients as it suggests that black people are distinct from all other humans which raises the question about the racial bias and validity of this study.
The multiplier of 1.12 was implemented by an analysis of clinical trials demonstrating that individuals who self-identify as African American had higher creatinine levels in their blood. It was thought the reason for the high creatine levels was due to muscle mass and diet. However, creatine levels are due to age, sex or body weight not muscle mass, two different components of a human’s composition. Furthermore, this multiplier may be problematic in patients who identify as biracial, who don’t sit under a single racial bracket. In short, race is a social construct and should not be taken into consideration as a biological concept in medical care.
In a recent analysis conducted by eClinicalMedicine, it was found that if the practice of adjusting estimated glomerular filtration rate (eGFR) based on race were eliminated, a major percentage of Black patients would receive diagnosis or be put in a transplant wait list.
Image No.1:
To see how the old equation truly affect the Black patient population, there was a survey done by National Health and Nutrition Examination in 2015-2018 that took account the unweighted and weighted sample size by the estimated eGFR using the MDRD equation with and without the race coefficient in Black Adults.
Image No.2
To have a healthy kidney function the GFR scale should compute a number of more than equal to 90. The findings of this survey indicate that when including race-specific adjustments in estimating the average GFR has a significant impact on Black patients who have kidney function levels between 20-60 mL/min/1.73 m2, classifying them as G4 (severely decreased kidney function). Without the race adjustment, the percentage of Black patients falling into this range significantly increases from 6.2% to 16.6%. In addition 1.7% black patients had GFR scores below 30 mL/min/1.73 m2, indicating a stronger adversity in kidney function. However due to race adjustments included in the GFR scale that percentage dripped by 0.7 percent, representing 300,000 black patients in this category who go undiagnosed.
Conclusion:
Recently in 2021 through deep research and debates the multiplier has been taken out of the GFR equation. However a major and concerning number of more than 3,000,000 black patients in 2015-2018 would have been referred to a specialist or been diagnosed with CKD if they eliminated the race multiplier in the GFR equation. Throughout history minorities in emphasis to Black Americans are more likely to be neglected in medical care, having a higher average mortality rate than their white counterparts. It is up to our current generation to fix these scraps and build bridges to make sure to provide equity and equality in healthcare.
Tsai, J. W., Cerdeña, J. P., Goedel, W. C., Asch, W. S., Grubbs, V., Mendu, M. L., & Kaufman, J. S. (2021, November 19). Evaluating the impact and rationale of race-specific estimations of kidney function: Estimations from U.S. Nhanes, 2015-2018. EClinicalMedicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8608882/
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