Everything you need when your dog or cat has kidney disease

There is no single number, but for many cats the disease unfolds slowly, over months and often years, and cats diagnosed at an earlier stage often live years of comfortable life with diet and monitoring. What you feed makes a measurable difference: in one study, cats on a renal diet lived a median of 633 days against 264 days on a normal diet.

IRIS stages 1 to 4 grade how far kidney disease has progressed, based mainly on blood creatinine and SDMA, then substaged by urine protein and blood pressure. Stage 2 is often picked up on a routine senior blood test before a pet seems ill, and it is the point where the best-evidenced treatments start to earn their place. By stage 4 the focus shifts firmly towards comfort and quality of life. Our stage checker turns your pet’s numbers into a stage in plain English.

Yes. The renal diet stands almost alone in having been tested in randomised controlled trials and shown to reduce uraemic crises and kidney-related deaths, which is why vets treat it as the cornerstone of management. In cats it more than doubled median survival in one study. Renal diets are generally introduced from IRIS stage 2 onward, the point where the evidence for benefit is clearest.

Yes. In a survey of nearly 400 owners giving their cats fluids at home, 85 percent described it as easy, low stress or at least okay for themselves, and 89 percent said the same for their cats. Vets most often recommend home fluids in the more advanced stages, IRIS 3 and 4. Fluids are supportive rather than curative, but they ease the nausea, lethargy and poor appetite that dehydration makes worse.

Yes, in ways that change the priorities. In cats it is most often a slow, age-related wearing out of the kidney’s filtering tissue. In dogs it more often involves the tiny filters becoming leaky, which is why protein in the urine takes centre stage in dogs in a way it does not in cats. Inherited forms matter more in dogs and can affect dogs only a year or two old, and the canine form tends to progress faster with a generally worse prognosis.

Increased drinking and increased urination are usually the earliest outward clue: refilling the water bowl more often, or larger clumps in the litter tray. Gradual weight loss, a reduced or fussier appetite, a duller coat and occasional vomiting often follow. None of these is dramatic, and each is easy to put down to age, which is exactly why kidney disease is so often caught later than it could be. Many cases are picked up on routine senior bloods before any signs at all.

No. Chronic kidney disease usually progresses over time and cannot be reversed. But progresses over time is the important phrase: for many pets it unfolds slowly, and good management can meaningfully slow it and keep quality of life high along the way. The goal is not to cure the kidneys but to slow the disease, ease its effects and keep your pet comfortable and happy for as long as possible, and modern veterinary medicine is genuinely good at that.

A prescription renal diet typically costs somewhere in the region of £20 to £50 a month for a cat, and more for a dog, scaling with size. The common medicines each run from a few pounds to £20 or £30 a month, a monitoring visit from several tens of pounds to over a hundred, and a crisis needing a hospital stay several hundred pounds or more. One honest caveat: once diagnosed, kidney disease counts as a pre-existing condition, so standard insurance will not cover a problem your pet already has.