What are the chances of you needing a second kidney to survive?

If you give a kidney as a living donor, what are your chances of dying for that reason afterwards because your one kidney failed and you needed a second kidney? What are the chances of an average person having only one working kidney at the end of their life?

I tried searching for it but couldn’t turn up anything.

Another question that is probably even harder to answer is what percentage of living donors died after they couldn’t do a more effective treatment that requires having two kidneys instead of one?

Pretty slim. A single kidney functioning at 75% of its normal capacity can sustain life very well. And if that fails, hemodialysis or peritoneal dialysis can sustain life, although it’s kind of a crappy life, which is why we want to encourage kidney donation as much as possible.

Kidney donors have no shorter lifespans than non-donors, although they do have an increased risk of developing End Stage Renal Disease (ESRD) at some point, when compared to healthy non-donors. When compared to the whole population, their risk of ESRD is lower than average, but that’s because you have to be healthy to donate a kidney. But, again, you can survive with ESRD quite a long time with dialysis, even if you only have one kidney.

http://www.kidneyregistry.org/living_donors.php?cookie=1

As mentioned in the link above, if a living donor ever needs a donation himself, he gets extra points which move him up on the waiting list. I can’t provide a cite but I remember reading a newspaper article explaining the situation. The extra points can’t guarantee that he’ll get the kidney he needs, but makes it pretty likely that he will provided he is otherwise in reasonably good health.

A meta-analysis published in 2015 reported that kidney donors seem to have a 5% increase in all-cause mortality over 25 years. So there is increased risk to health, but it’s pretty small.

Another study http://www.ncbi.nlm.nih.gov/pubmed/26854790 found that only 0.6% developed end-stage renal disease (the major reason for kidney transplants) after 25 years.

What is the probability that a person who develops kidney failure will develop kidney failure in both kidneys both at once? Do diseases that damage the kidneys tend to be systemic and hit both kidneys? Or do they tend to be local to one kidney? (Obviously, a traumatic injury only hits the body parts it hits and may damage just one kidney.)

If a person with just one kidney suffers failure of that one, what is the probability that if he still had both kidneys, both would have failed anyway?

Around 100%. The primary causes of chronic kidney disease are diabetes and hypertension, which are systemic and affect both kidneys. Practically everyone who develops chronic kidney disease and progresses to end-stage renal failure has it affect both kidneys.

That said, a donor is at theoretical risk for developing a form of kidney injury that occurs as a result of having only the one kidney left. In other words, donors are at risk for a unique form of kidney injury.

Specifically, in a donor, the remaining kidney has to ‘work twice as hard as it used to’. Doing so, adds a hemodynamic stress to the remaining kidney, i.e. it must filter twice as much blood as it would have otherwise. Such ‘hyperfiltration’ can lead to kidney damage (and is a main contributor, for example, to the development of kidney disease in people with diabetes).

ETA: This post was directed to Senegoid as much as spamforbrains.

only 0.6% experience this hyperfiltration damage. Not zero, but not all that high. You’re more likely to die in a car crash.