I am going to try to recap my recent grand rounds on race and GFR in a few #tweetorials. Here is the fourth one. You can find the presentation files and a video of me presenting at pbfluids.com/2021/12/the-ne………… 1/10
So both MDRD and CKD-EPI found that Black Americans had a higher GFR (on average) for the same creatinine compared to White Americans. Also NHANES showed that Black people have higher creatinines than White people. Why? ajkd.org/article/S0272-… 2/10
Looking at non-creatinine determinants of GFR there are a limited number of variables. Though I included "metabolism" that only comes in play at high serum creatinine so that can't be the factor here.

Increased production from increased muscle mass was the prime suspect. 3/10
In the 1999 MDRD study, Levey et al. presumed that the increased GFR in Black Americans was due to increased muscle mass. They provided 3 references for this and they are a clown show 🤡 4/10
Black people having Increased muscle mass is a longtime racial stereotype that was largely accepted by medicine. But when people did question this it doesn't hold up.
Looking at serum Cr can be difficult because it is confounded by GFR, so Hsu et al looked at anuric dialysis patients and found here, with a GFR of zero, Black people still had higher serum Cr, and surprisingly, adjusting for muscle mass DID NOT eliminate the differences!😮 5/10
Levey and Co did an analysis to see if they could remove race from the GFR equations by replacing it with height and weight, presuming that if race was a proxy for size, this would work pretty well. Nope. Adding height and weight did not account for the differences. 6/10
So we know that Black people in our study samples have high GFR for the same Cr but we don't know why. I think it is diet but GI excretion is possible. Tubular secretion falls down because of anuric dialysis studies

But we really don't know and we should investigate this 7/10
Despite not knowing why it performs this way, eGFR provides a signal of increased health in a group of people who have worse kidney outcomes. This is perverse. 8/10
Anyone who has visited a few dialysis units in the US can't avoid noticing the racial disparity. Black Americans face almost 3 times the incidence of ESKD as White people. 9/10
But what is less well known is that the prevalence of CKD is almost the same

Black Americans: 16%
White Americans 15.7%

Despite the same rate of CKD Black people reach ESKD 3x more often. Delaying diagnosis in this group is counter to any sane public health policy. 10/10

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More from @kidney_boy

10 Dec
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
Read 11 tweets
9 Dec
I am going to try to recap my recent grand rounds on race and GFR in a few #tweetorials. Here is the third one. You can find the presentation files and a video of me presenting at pbfluids.com/2021/12/the-ne……… 1/10
In the 1980's the hot idea in nephrology was low protein diets to preserve GFR. The NIH funded a Big Science study to test the theory, the Modification of Diet in Renal Disease study, MDRD. The study was a mess and fell on its face, but they did collect a lot of cool data! 2/10
Among that data was iothalamate clearances which are a really good approximation of GFR. So Andy Levey and friends took those data and combined it with age, gender, and race to come up with the MDRD formula. 3/10 Image
Read 10 tweets
8 Dec
I am going to try to recap my recent grand rounds on race and GFR in a few #tweetorials. Here is the second one. You can find the presentation files and a video of me presenting at pbfluids.com/2021/12/the-ne…… 1/10
To understand how nephrology got itself into this eGFR and race mess I want to unpack what is going on in the equations. What are they trying to do and how do they work. 2/10
Estimated GFR depends on people being in steady state. Steady state means the Day 1 creatinine = Day 2 creatinine = Day X creatinine. It doesn't matter if the cr is 0.6 or 4.4, as long as the cr is roughly the same from day to day they are in steady state. 3/10 ImageImageImage
Read 11 tweets
8 Dec
I am going to try to recap my recent grand rounds on race and GFR in a few #tweetorials. Here is the first one. You can find the presentation files and a video of me presenting at pbfluids.com/2021/12/the-ne… 1/10
My parents grew up in the segregated south and tell me stories of toe curling segregation. They are embarrassed to say that at the time, it seemed normal. 2/10 Image
What are we doing today that we will look back at as being unconscionably racist?

I think we will look at the two separate GFRs listed on a routine BMP like the two drinking fountains. 3/10 Image
Read 10 tweets
2 Dec
More fellows find NephJC to be “very effective” than:
CJASN, NephSAP, JASN, textbooks, KDIGO, AJKD, journals, RFN, and more. Wow. Just wow. asn.apprisor.org/epsAbstractASN…
The breakdown by medical school is interesting. Social media has better penetration among US grads
48% for NephJC
42% for NephMadness
And not surprisingly, was more popular among younger fellows.
Read 4 tweets
9 Nov
More drinking games with ⁦@BookBurton⁩: the myth of breaking the seal.
The set up for the ultimate nephrologist
party game
Then @Jwaitz invents Edward Licorice hands but @LeticiaRolonMD had already played it!
Read 4 tweets

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