Prevalence estimates depend on the cats' ages, the study method and the definition of disease. The percentage in the introduction therefore cannot be applied as a precise prediction for every older cat. Kidney disease can also occur in a young animal, for example because of a congenital abnormality.
When to see a vet urgently
Contact an emergency vet immediately if your cat develops any of these signs:
- unsuccessful straining to urinate or clearly reduced urine output;
- repeated vomiting and inability to keep food or water down;
- collapse, severe weakness or altered consciousness;
- sudden blindness, seizures or marked confusion;
- difficulty breathing, particularly during fluid treatment.
Sudden deterioration needs investigation even in a previously stable CKD patient. You can find a vet near you.
Overview
The kidneys are central to maintaining normal body function: they clean the blood, regulate blood pressure and contribute to calcium and phosphorus metabolism. In CKD, their functional tissue is gradually replaced by scar tissue, impairing function throughout the body. The disease cannot be cured, but appropriate treatment can slow progression and provide a good quality of life.
Causes
Chronic kidney disease can develop as a primary condition or a complication of other illnesses:
- inherited predisposition, including polycystic kidney disease in Persians, Abyssinians and Maine Coons
- chronic urinary tract infections
- urinary stones
- glomerulonephritis and pyelonephritis
- amyloidosis
- poisoning and use of nephrotoxic medicines
- ageing
Breed associations do not mean the same disease affects every breed listed. The inherited PKD1 mutation is recognised particularly in Persians and cats with Persian ancestry. In Abyssinians, the recognised inherited kidney disease is amyloidosis, in which an abnormal protein accumulates in tissues. Breed name alone does not confirm either diagnosis.
The original cause remains unknown in many CKD patients. Previous acute kidney injury can also leave permanent damage. However, an ordinary episode of lower urinary tract symptoms does not automatically mean kidney infection or later chronic kidney disease.
Risk factors
Kidney problems occur more often in cats that:
- are over 7–8 years old
- belong to certain breeds, including Persian, Abyssinian, Maine Coon and Burmese
- have had chronic urinary tract disease, including FLUTD or urinary stones
- have experienced poisoning or severe infections
- have eaten dry food without enough water intake
An independent role for dry food in causing CKD has not been established clearly enough for dry feeding alone to explain the disease. Kidney diets are also available in both dry and wet forms. Adequate water intake matters, but the overall diet and individual situation determine the approach.
The precise effects of most risk factors vary between datasets. Age is an important reason for monitoring, but investigation of a symptomatic young cat should not be delayed because of age. Monitoring also considers weight, muscle condition, blood pressure and trends in previous results.
Main symptoms
CKD develops slowly, and early stages may have no symptoms. Typical signs include:
- increased thirst, or polydipsia
- increased urination, or polyuria
- loss of appetite and weight
- listlessness and reduced activity
- nausea and vomiting
- uraemic bad breath
- poor coat condition
- dehydration
- seizures and neurological problems in advanced disease
Increased drinking does not always replace water lost in dilute urine. A cat can therefore drink more than before and still become dehydrated. Gradually decreasing muscle mass and changing appetite may be less obvious warnings than clear vomiting.
Sudden worsening may result from dehydration, an obstruction or another additional illness, for example. It is not automatically interpreted as the expected final stage of CKD. Some of this functional decline may improve even though the underlying chronic damage remains.
Complications and consequences
Without treatment, CKD leads to:
- uraemic toxicity
- anaemia
- high blood pressure
- mineral metabolism disorders, including osteodystrophy
- heart failure
- death
This list does not mean every cat develops every complication. Anaemia may relate to a shortage of the kidney hormone that directs red blood cell production. High blood pressure can damage the eyes, brain, heart and kidneys. Heart failure is not an inevitable consequence of CKD, but concurrent heart disease affects factors such as fluid treatment safety.
Chronic kidney disease stages according to IRIS
The vet determines the stage using the international IRIS system, based on blood creatinine and SDMA when the cat is stable:
- stage 1: kidney function is already impaired, but creatinine is within the reference range, below 140 µmol/l;
- stage 2: creatinine 140–250 µmol/l, often without symptoms yet;
- stage 3: creatinine 251–440 µmol/l, with thirst, weight loss and vomiting developing;
- stage 4: creatinine above 440 µmol/l, with severe uraemia.
Urine protein, measured by the protein-to-creatinine ratio, and blood pressure are also assessed. Treatment depends on stage and includes a kidney diet, phosphate binders, control of blood pressure and proteinuria, and treatment of anaemia. “Chronic renal failure” is an older term; chronic kidney disease is now used.
The symptom descriptions for stages are approximate: cats at the same stage can feel very different. Stage 1 requires other evidence of kidney disease, rather than simply creatinine within the reference range. One abnormal result or individual IRIS threshold does not alone confirm CKD.
Kidney failure can still describe markedly impaired function. Chronic kidney disease is a broader term that also includes early stages without obvious failure. Staging follows an established diagnosis and is reviewed when the cat's condition changes.
Diagnosis at the vet
Confirming the diagnosis involves:
- a complete blood count and biochemistry, including urea, creatinine and SDMA
- urinalysis for concentration, protein, bacteria and crystals
- kidney ultrasound for structural changes, cysts and tumours
- blood pressure measurement
- X-rays if urinary stones are suspected
Creatinine is also affected by muscle mass and hydration. In a thin cat with muscle loss, the value may be lower than expected. Dehydration can temporarily raise it. SDMA, urine concentration and repeated results help interpret the overall picture.
The urine protein-to-creatinine ratio indicates protein loss, but its source is assessed before treatment decisions. Blood pressure is measured calmly and compared with eye and other organ findings. Ultrasound may show cysts, an obstruction or structural changes even when blood results are not yet clearly abnormal.
Treatment and home care
Food and adequate nutrition
The benefit of a kidney diet comes from its nutrient composition, particularly phosphorus control. Suitable food is chosen according to disease and eating habits, and introduced gradually. Do not leave your cat without food to make it accept a new diet. Nausea and other causes of poor appetite are treated at the same time.
Maintaining muscle is also a goal, so feeding does not aim simply for the lowest possible protein intake. Tell the practice what and how much your cat actually eats. If blood phosphorus stays high despite diet, a phosphate binder selected by the vet may be needed.
Symptoms are treated according to findings
Nausea, dehydration, anaemia, high blood pressure and protein loss are treated separately where needed. A potassium supplement may help a confirmed deficiency, but is not automatically given to every cat with CKD. The need for vitamins and other supplements is also assessed according to food and test results.
Fluid treatment needs and administration are agreed individually. Subcutaneous fluids at home require training and a prescribed plan. Extra fluid is not harmless for every cat: fluid loading needs particular monitoring in a cat with heart disease. Contact the practice immediately if breathing becomes difficult.
Monitor daily life alongside tests
Record weight trends, eating, drinking, urination, vomiting and activity. Muscle condition is assessed alongside weight, as an unchanged weight can hide tissue changes. Check-up frequency depends on disease stability, medicines and identified problems; do not wait for the next scheduled visit if symptoms change.
Prevention
CKD cannot be prevented completely, but risk can be reduced and progression slowed through:
- regular veterinary checks for cats over 7 years old
- annual blood and urine tests
- blood pressure monitoring
- free access to drinking water, including fountains, for example
- special diets to support the kidneys
- early treatment of infections and urinary stones
Do not start a kidney diet in a healthy cat simply because of age or breed without nutritional assessment. In confirmed CKD, diet and check-ups are matched to findings. Even good care cannot prevent every case, and a diagnosis alone does not show that the owner made a mistake.
What it means for owners
Chronic kidney disease is one of the most common diseases in older cats. It is important to understand that CKD cannot be cured completely, but with appropriate care a cat may live for years. Regular testing, diet and supportive measures extend life and maintain quality of life.
Good health lasting years is possible but cannot be promised for an individual cat. Prognosis depends on factors including stage, protein loss, blood pressure, maintaining appetite and weight, and other illnesses. Care goals also consider whether your cat can eat, rest and take part in enjoyable activities.
This material provides information and does not replace veterinary advice. Seek veterinary attention immediately when the first symptoms appear.
Frequently asked questions
Can a cat have CKD with normal creatinine?
Yes. In early disease, other findings such as persistently reduced urine concentration or a structural change may raise suspicion. Diagnosis is based on assessing several pieces of information and their trends.
Does drinking a lot mean my cat cannot be dehydrated?
No. The kidneys may lose so much water through urine that increased drinking cannot replace it. Fluid needs are assessed during examination; do not give extra fluids at home without a plan.
Must I change to a kidney diet all at once?
No. Change gradually in a way your cat accepts. Ensuring food intake and treating any nausea are the priorities. Contact a vet if your cat stops eating.
This article is for general information only and is not a guide to treatment. If you notice the first signs of illness, contact your vet.
Paw4care editorial team
Sources
- 2026 iCatCare Consensus Guidelines on the Diagnosis and Management of Chronic Kidney Disease in Cats, iCatCare / Journal of Feline Medicine and Surgery, accessed 2026-11-03.
- IRIS Guidelines: 2026 Revisions, International Renal Interest Society, accessed 2026-11-03.
- Chronic Kidney Disease, Cornell Feline Health Centre, accessed 2026-11-03.
- Chronic Kidney Disease in Cats, VCA Animal Hospitals, accessed 2026-11-03.
- Polycystic Kidney Disease (PKD1), UC Davis Veterinary Genetics Laboratory, accessed 2026-11-03.
- Renal Amyloidosis, Cornell Feline Health Centre, accessed 2026-11-03.
- Chronic Kidney Disease: Nutrition, NC State Veterinary Hospital, accessed 2026-11-03.
- Hypertension, Cornell Feline Health Centre, accessed 2026-11-03.
- Blocked Bladder in Cats, PDSA, accessed 2026-11-03.