One thing to keep in mind is there are many types of kidney dysfunctions. GP's tend to use the term "kidney failure" VERY loosely. Even kidney failure has different levels of severity. There is acute kidney failure, which can be reversible and the the kidneys can actually heal themselves after. There is also chronic kidney failure, which occurs over a long period of time and the kidneys may not be able to fully heal from, if at all.
There is also acute and chronic kidney dysfunction. More often than not, body builders and those that train heavily tend to have acute kidney dysfunction. We rain too hard, don't drink enough water, eat too much damn food, and use supplements that can raise our blood pressure. Typically we fall into the category of acute kidney dysfunction because of those factors, which is treatable and usually reversible with little to no long term negative effects. If left untreated and unchecked, acute kidney dysfunction can progress into chronic kidney failure, which is super bad juju.
Not a big fan of WebMD, but they actually have a good quick article on the topic that explains things really well.
Acute Kidney Injury Versus Chronic Kidney Disease-Topic Overview
Long story short, just because you go to the Doc and get some blood work done he says the words "kidney failure" does not mean it's time to freak the fuck out and try to get on the transplant list. Take it seriously, make some changes to your diet, training and lifestyle and go back for blood work again in a few weeks. And always keep your blood pressure under control. They call elevated blood pressure the "silent killer" for a reason. Monitor your BP regularly, take your meds if you have them, and do some fucking cardio. We all neglect to do as much cardio as we should. It helps with keeping BP under control, keeping you lean and generally healthy. I just got off of the hamster cage myself. It sucks a fat dong, but we all need to do more of it. Cardio I mean, not sucking fat dongs. Unless that's your thing, in which case, carry on.
