I have one kidney that's a little deficient, but the other is basically so kick-ass that it doesn't matter. Good thing for me since I like coffee and alcohol, eh?
How do I treat it? Hmm...well, I can't exactly
give up being diabetic, so I've been put on ACE inhibitors, which I've been told reduce pressure around the kidneys and eyes to reduce diabetic damage. I try to keep my blood sugar level under control as well, and nothing seems to help more than exercise. My microalbumin count is ~5 mcg/mg, so I'm doing perty well.
Diabetic since 5 years old, btw, now 24.