Guest post by Paul Williams, PhD
Chronic kidney disease (CKD) affects over 37 million Americans. In 2022, two preeminent kidney organizations made changes in their diagnosis of CKD. These changes were not the result of scientific discovery, but rather the National Kidney Foundation (NKF) and the American Society of Nephrologists (ASN) bowed to political pressure to ignore biological differences between races.
The changes are projected to disqualify medical treatment in 5.51 million and curtail treatment in 4.59 million White, Hispanic, and other non-Black adults with CKD. This was done in order to qualify 434,000 ostensibly unaffected Blacks for CKD treatment and to expand treatment opportunities in another 584,000 Black CKD patients.
Kidney health is measured by “glomerular filtration rate” or “GFR”. True GFR can be directly measured, but this is both expensive and inconvenient. For over two decades, GFR has been estimated from creatinine levels in the blood.
High blood creatinine means poorer kidney function (lower GFR) and lower creatinine means better kidney function (higher GFR). Nearly 250 million creatinine measurements are performed each year in the US.
On average, blood creatinine levels are higher in Blacks than non-Blacks having the same kidney health. Therefore, accurately estimating GFR requires increasing Black GFR between 16% and 21%. For this reason, blood work provided by doctors used to include one GFR estimate for African Americans and one for non-African Americans, but not anymore.
Charges of racism were made because a Black patient might receive a different CKD diagnosis and treatment than a non-Black patient with the same blood creatinine. There was, in fact, no discrimination because Black and non-Black patients received precisely the same diagnosis and treatment based on the best estimate of their true GFR, which is not the same as creatinine.
Newspaper, magazine, or Internet articles that labeled the GFR race correction as “racist” failed to recognize the difference between creatinine and true GFR. So did medical students, social justice advocates, and doctors-turned-activists who successfully petitioned hospitals to remove race from their GFR calculation. They claimed that “the use of race to estimate kidney function (i.e. estimated glomerular filtration rate or eGFR) is rooted in historical injustice and a legacy of justification for colonization, slavery and genocide.”
Succumbing to pressure from student-led protests and government pressure, the NKF and ASN leadership decided to eliminate race in the estimation of GFR and then to select a Task Force sympathetic to their decision.
In alignment with the NKF and ASN leadership, Task Force unanimously agreed that race should be ignored when estimating GFR. They endorsed a new “race-free” estimate of GFR that favored the diagnosis of CKD in Blacks and disfavored CKD diagnosis in non-Blacks.
The Task Force was heavily weighted in favor of minority representation. The distribution of US adults with CKD is estimated to be 68.6% White, 12.5% Black, 12.3% Hispanic, and 6.5% Asian or other racial groups. These proportions suggest that Blacks were overrepresented in the 14-member Task Force by a factor of four, while non-Hispanic Whites were represented by less than a third of their due.
By ignoring the Black-White creatinine difference, the new race-free 2021 equation would appear to place Blacks at a higher risk for CKD than Whites, i.e., 7.9% vs. 5.8% of the adult population between 2005-2008 had CKD, 8.5% vs. 5.9% between 2009 and 2012, 8.4% vs. 6.3% between 2013 and 2016, and 9.1% vs. 6.3% 2017-2020.
However, when correctly calculated by recognizing the creatinine-race difference, the proportion of Americans with CKD was actually greater in non-Hispanic Whites than Blacks: 8.6% vs. 5.6% between the years 2003 and 2006; 7.5% vs. 5.8% between 2007 and 2010, 8.5% vs. 6.1% between 2011 and 2014; and 8.4% vs. 6.6% between 2015 and 2018. Today, the biased race-free GFR is reported by the CDC and the NIH to support the narrative that Blacks are at greater CKD risk than Whites when actually the opposite is true.
There are other consequences of the new race-free 2021 equation beyond CKD diagnosis. The race-free equation is projected to deny 92,000 Whites and other non-Blacks referrals to nephrologists and preparation for dialysis (fistula placements) so that they can be offered to an additional 59,000 Blacks who are less likely to need them.
Medicare coverage of kidney disease education and medical nutrition therapy will be withheld from 1.9 million non-Blacks so that they may be offered to 206,200 additional Blacks. Many reports show Blacks already receiving better treatment for CKD than Whites even before the introduction of the new race-free equation, including ACEi, ARB and statin treatment, nephrology care, and urine albumin-creatinine ratio testing (Blacks lag behind Whites for SGLT2i and GLP-1RA medications). Blacks along with their usual care physician are also more aware of their CKD status than White patients.
The creation of the Task Force was rationalized on the basis that: “race is a social and not a biological construct, the problematic nature of applying race to clinical algorithms, and the need to advance health equity and social justice.” These are political stands, far removed from the primary task of saving lives.
The Task Force failed its promise to deliver an unbiased decision with acceptable performance characteristics (they misclassified eleven million patients) that does not disproportionately impact any specific group (biased in favor of over-diagnosing Black and under-diagnosing non-Black patients). Never does the Task Force explain why excluding race more than compensates for the millions misclassified by the race-free GFR estimate.
Over 70% of lab reports have converted over to race-free calculation with no option to retrieve its less biased predecessors. The new race-free GFR estimate may be a harbinger of future changes in medical treatment that are driven by racial politics rather than science.
These and other issues are described in a recent peer-reviewed article in the science journal Cureus. The article was motivated by the lack of transparency in the NKF/ASN decision to eliminate the race coefficient. It offers an alternative approach, a stratified analysis, that used only Blacks to estimate Black GFR and only non-Blacks to estimate non-Black GFR.
Unfortunately, despite providing the least biased GFR estimates for both Blacks and non-Blacks, the NIH-funded CKD-EPI collaboration that gave rise to this stratified analyses refuses to release its formula.