I have never worried about an eGFR in the 50's , which continued for maybe 20 years, and it never came up with my doctors. I have an autoimmune disease so when it dipped to 36 I did worry, but it is back in the mid-40's.

I just want to say that the dietary advice I get is very different from the usual. I am encouraged to have more salt and "push protein." I did see a nephrhologist and see her every year. and she feels that my low blood pressure could be a factor, hence the salt. Also muscle loss can affect the eGFR, hence the protein. I had an echocardiogram in case heart function might be slowing filtration rate, and my heart was fine.

Time will tell if this advice is wise. I do not have diabetes or high blood pressure. My autoimmune labs are highly positive but there is no evidence that that is the cause of my drop in eGFR. I am often dehydrated, I am sure.

I don't want to repeat myself too much on kidney threads but again, the Cystatin C give a different eGFR that is not as affected by the factors that affect the creatinine based one, and my Cystatin C is still in the low 50's which is reassuring.