I'm drawn to this area of research because my GFR (based on creatinine I believe) had dropped from 54 to 47 over a few months. Two insights I've seen are: While GFR is a preferred measure of kidney function, it doesn't provide the best measure of ""disease severity", the better measures are proteinurea and albiminurea. That coud be a discussion to have with your specialist. I'll be looking at that at my next visit.
The other revelation seems to be that kidney disease is at least partly related to inflammation, so that's one factor to look at.
I believe the studies that contained those http://www.sciencedaily.com
Two other studies found that substances that can tame inflammation can cause improvement in kidney function. Get ready to disbelieve: baking soda is one substance that has apparently shown some efficacy; while curcumin (2 500 mg doses per day—taken with a soluble fat because it doesn't easily pass into the bloodstream—can also have multiple positive effects on sensitive organ structures. I also have neuropathy in my legs so I'm experimenting with curcumin. Sometimes it seems to be working. I'll know after a month or two.
Wishing you the best!