Thread by @kidney_boy

I am going to try to recap my recent grand rounds on race and GFR in a few #tweetorials. Here is the fifth one. You can find the presentation files and a video of me presenting at pbfluids.com/2021/12/the-ne…………… 1/10

Use of race in eGFR is doesn't work because race is a social construct. “A person who could be categorized as black in the United States might be considered white in Brazil or colored in South Africa” Racial identity shifts with experience and time. 2/10 nytimes.com/roomfordebate/…

I spoke Danish at home. I ate Danish food. At Christmas we danced around the Christmas tree singing Danish carols. But when I went outside my home, I was black. nytimes.com/roomfordebate/… 3/10

If race is a social construct, why do Black people have more aggressive kidney disease?

Some of the risk is due to social determinants of health
Some of the risk is biologic

4/10

APOL1 risk variants, race, and progression of chronic kidney disease

Fig 1: APOL 1 is autosomal recessive, 2 risk alleles to be affected
Fig 2: Black people without 2 risk alleles do not have a different rate of eGFR decline from White people. 5/10

nejm.org/doi/10.1056/NE…

nejm.org/doi/10.1056/NE…

Fig 3: there IS a gap between unaffected Black people and White people. This could be filled with additional undiscovered genetic variants or social determinants of health. 6/10

The APOL1 phenotype (i.e. two risk alleges) is found is 23% of the AASK cohort and 19% of the CRIC cohort. About 43% of Black Americans have a one copy of a risk allele (there are two risk alleles G1 and G2). 7/10

Since a single copy of an APOL1 risk allele protects against Trypanosoma brucei rhodesiense and Trypanosoma gambiense the genes are most prevalent where those parasites are endemic. Few in Eastern Africa carry the risk allele (purple region). 8/10 doi.org/10.3165/jjpn.2…

In the last few years Nephrology has been coming to terms with the recognition that race is a social construct and the risk we used to attribute to race is largely a genetic phenotype found in a fifth of Black Americans. 9/10

Nephrology is realizing that we built the entire concept of CKD around a GFR that misclassifies Black Americans as more healthy.

The realization and recognition came from medical students who rejected what nephrologists largely accepted. 10/10

I accepted that race would affect GFR in 1999 and didn't question it until med students and nurses and scribes and patients began asking questions. 11/10 ted.com/talks/dorothy_…