I think the question as to whether cats with renal failure suffer is a good one. This is because (a) a lot of elderly cats suffer from kidney failure and it is quite a common cause of death and (b) cats as we know are notoriously good at hiding the fact that they feel pain.
I can only look at this question from two points. Years ago, my elderly female cat suffered from kidney failure. To me, she looked as if she was in discomfort at the very least and probably in pain by which I mean chronic pain. I remember her looking up at me while I was feeding her and the look in her eyes told that this was enough and it was time to say goodbye. She spent a lot of the time sleeping, curled up, outside on the cool grass.
On one occasion she slept in the car park outside the flat right over a drain. I took this to mean that she wanted the cooling air passing through the drain to ease her discomfort. This is my personal experience. It is painful for me, now, to think of this.
On a more scientific and less anecdotal level, with respect to humans, kidney failure can cause pain indirectly. In other words the malfunctioning the kidneys causes other health issues in the body which can cause discomfort and/or pain.
On this basis, I would conclude that cats can feel pain and suffer if they have kidney failure. I think that this is quite an important observation because it may well be a factor in deciding whether to euthanise your cat or not because, as mentioned, kidney failure often happens towards the end of a cat’s life.
There comes a time with kidney failure when a cat’s owner must turn their mind quite seriously to whether they decide to euthanise their cat or not. The fact that a cat feels chronic (i.e. permanent) discomfort and/or pain must be a major influence in the decision making process.
There is, in fact, a page on this website written by veterinarian which will help you assess whether your cat is in pain or not. Please click on this link to read it.
Photo: Al Barsha Veterinary Clinic. My sincere thanks…Michael.