There's TONS of talk about kidneys in the bodybuilding community. I think the coaches do look at the kidney labs as there's been so much talk about. All the "top" ones I've seen on social media say they do it, it's a priority it seems. That's aside from the wisdom of laypersons playing doctor; just making sure I'm not misunderstood LOL. But if your experience hearing about coaches is different I have no reason to doubt you.
Dante Doggcrapp touts the herb astragalus. Says he's brought back MANY pros and amateurs from the brink of kidney failure with it, along with stopping the juice. 2 grams morning and night, Vitamin Shoppe brand IIRC. It lowered my creatinine and tons of similar testimonials on the forums, seems reliable in that respect. Question in my mind is if it just lowers lab values, sort of as a fake indicator, or is it actually protecting the kidneys. Thought I'd mention it in case someone here has highish creatinine and wants to try it. Check the brand to make sure, apparently NOW foods for example doesn't work. Dante recommends all juicers to use it proactively, I don't think it will hurt. Are you familiar with it Coach?
AI Overview
Astragalus (Huang Qi) is an herb used in Traditional Chinese Medicine known for its potential to protect the kidneys. Research suggests it may help slow the progression of chronic kidney disease (CKD) by reducing inflammation, preventing kidney scarring (fibrosis), and improving blood flow
Key Benefits
Slows Kidney Decline: Studies, including recent multi-center trials in diabetic patients with CKD, suggest astragalus can help stabilize the estimated glomerular filtration rate (eGFR) and slow kidney function decline.
Reduces Proteinuria: It is frequently investigated for its ability to lower protein in the urine—a major indicator of kidney damage and disease progression.
Antioxidant & Anti-Inflammatory: Compounds in the root, like astragaloside IV, help protect kidney tissues from oxidative damage and reduce inflammation.
Supports Diabetic Nephropathy: Because astragalus also helps lower blood sugar and improve metabolic function, it is heavily researched as an adjunctive treatment for diabetic kidney disease
As far as kidney labs go, one of dj's favorite youtubers, Pro BB Dr Todd, I think he's an actual MD, claims the GFR and creatinine value are worthless for a bb, you need to get your Cystatin-C. He has an arrogant style so I haven't watched much.
There's a bunch of meds that theoretically could help protect bb'ers kidneys when used prophylactically, and many use them, but my posts get too long 
I agree with taking Cystatin into consideration. But if you get labs back that suggest you’re in or heading towards 4th Stage CKD even if you might be at a 3a or b and Urine tests come back you’re dumping protein Its not a “coaches” call to play doctor. It would call for kidney/bladder imaging to see if there’s if it’s temporary injury or permanent damage.
If your Creatinine is right around 1.8-2.0 + and your eGFR is in the 40’’s or 30’s chances of heading back to normal numbers are almost 0. Depending on the damage you might expect if stage 4 with an eGFR lets say 30, might be able to recover at 34-36.
It’s absurd to say those baselines are “worthless”
Find a Nephrologist that deals with athletes not one only for the general public