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Chronic Kidney Disease in Cats: Signs, Stages and Care

Chronic kidney disease affects up to 40% of cats over 10. Early signs, how it's diagnosed and staged, kidney diets, fluids and what to expect.

Updated October 2026 · 9 min read · By the Hushku editorial team · 2 sources

Short answer

Chronic kidney disease (CKD) is one of the most common illnesses in older cats, affecting up to 40% of cats over 10 and 80% over 15, according to Cornell's Feline Health Center. It can't be cured, but a kidney diet, good hydration and treatment of blood pressure and anaemia can keep many cats well for years, especially when it's found early.

Key facts

CKD affects up to 40% of cats over 10 and 80% over 15.
SDMA can detect kidney disease earlier than creatinine.
About 60% of cats with CKD develop high blood pressure.
A kidney diet and good hydration can slow progression.

Definition

Chronic kidney disease is a gradual, irreversible loss of kidney function. As the kidneys fail, they can't concentrate urine or remove waste, leading to dehydration, nausea, weight loss and high blood pressure.

The kidneys have a lot of spare capacity, so cats often show no signs until much of their function is lost. That's why routine blood and urine tests for senior cats matter: the SDMA blood test and a urine concentration check can pick up kidney disease earlier than creatinine alone, which usually rises only once about 75% of function has gone.

Vets stage CKD from 1 to 4 using the International Renal Interest Society (IRIS) system, based on blood tests, urine protein and blood pressure. The stage guides treatment and outlook.

Signs and symptoms

Drinking and peeing more
Weight loss and muscle loss
Poor or picky appetite
Vomiting
Poor coat and less grooming
Lethargy
Bad breath or mouth ulcers (later stages)
Sudden blindness from high blood pressure

Causes and risk factors

Ageing (the main risk factor)
Previous kidney injury, such as from lily poisoning or infection
Polycystic kidney disease in some Persian-related breeds
High blood pressure and hyperthyroidism, which interact with kidney disease

Treatment

A prescription kidney diet (lower phosphorus and moderate high-quality protein)
Hydration support: wet food, fountains and sometimes fluids under the skin at home
Blood pressure medicine if needed
Treatment for anaemia, nausea and low appetite
Regular rechecks every few months

Prevention

Twice-yearly senior check-ups with blood and urine tests
Keep lilies out of the house; they cause acute kidney failure
Encourage water intake
Keep teeth healthy and weight steady

What to expect

Outlook varies a lot. Cornell's Feline Health Center notes that cats diagnosed at stage 2 survive on average about 2 to 3 years in many studies, while cats at stage 4 average under 6 months. Earlier diagnosis and treatment are linked to better outcomes, and some studies report cats on kidney diets live considerably longer than those on standard food.

Getting your cat to eat a kidney diet

Switch slowly over several weeks, try different flavours and textures, and never let your cat go without food to force the change: a cat that isn't eating is at greater risk than one eating a non-kidney diet. Ask your vet about appetite stimulants and anti-nausea medicine.

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Sources

We check guides against veterinary sources and update them when guidance changes. How we write and review.

Questions.

Is kidney disease in cats painful?

CKD itself isn't usually painful, but nausea, dehydration and mouth ulcers make cats feel unwell. Treating these improves quality of life a lot.

Can kidney disease in cats be reversed?

Chronic kidney disease can't be reversed, but its progression can often be slowed. Sudden (acute) kidney injury is different and can sometimes recover with treatment.

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