The basics
What kidney disease in cats looks like
Chronic kidney disease (CKD) is one of the most common illnesses of older cats. It usually creeps in slowly, and the early signs are easy to put down to age.
Signs to watch for at home
- Drinking and peeing more: bigger clumps, a bowl that empties faster
- Weight loss, often slow, with muscle loss along the spine
- A smaller or pickier appetite
- Vomiting, or nausea: lip-licking or drooling near the food
- Bad breath or mouth ulcers
- Weakness, hiding or a poorer coat
Why finding it early matters
Kidney damage cannot be undone, but its pace can often be slowed. A kidney diet, enough water and blood-pressure control all work best when they start early. Many cats show nothing at all in the early stages, which is why yearly blood and urine tests, every 6 months once a cat is over 10, find CKD before the signs do.
At home, weight loss is the earliest sign that CKD is progressing. A weekly weigh-in catches it long before you would see it.
Source: ISFM Consensus Guidelines on the Diagnosis and Management of Feline Chronic Kidney Disease 2016 · AAHA/AAFP Feline Life Stage Guidelines 2021
IRIS staging
The stages of kidney disease in cats
Vets stage CKD with the International Renal Interest Society (IRIS) system: blood creatinine and SDMA set the stage, then blood pressure and urine protein refine it.
| IRIS stage | Creatinine (mg/dL) | SDMA (µg/dL) | Phosphorus target (mg/dL) | What it usually means |
|---|---|---|---|---|
| Stage 1 | under 1.6 | under 18 | 2.7–4.6 | No rise in creatinine, but other evidence of kidney damage, such as dilute urine, protein in the urine or changes on imaging. Usually no outward signs. |
| Stage 2 | 1.6–2.8 | 18–25 | 2.7–4.6 | A mild rise. Signs are mild or absent. |
| Stage 3 | 2.9–5.0 | 26–38 | under 5.0 | Moderate. Signs such as weight loss, a poor appetite and vomiting may appear. |
| Stage 4 | over 5.0 | over 38 | under 6.0 | Advanced. A higher risk of feeling unwell, and of crises that need hospital care. |
Source: IRIS Staging of CKD, modified 2023 (cats)
How staging works
Staging is done on a stable, well-hydrated cat, ideally fasted, and on at least two blood tests. A single result from a dehydrated or unwell cat can look worse than the kidneys really are, so FelineSense records the stage your vet gives and never stages the disease itself.
SDMA tends to rise earlier than creatinine and is less affected by muscle loss, which matters in thin older cats. When the two point to different stages, your vet weighs both. Urine specific gravity helps too: a cat whose urine stays below about 1.035 is not concentrating it well.
Source: IRIS 2023
| Systolic pressure (mmHg) | IRIS substage | Risk to eyes, brain, heart and kidneys |
|---|---|---|
| under 140 | Normotensive | Minimal |
| 140–159 | Prehypertensive | Low |
| 160–179 | Hypertensive | Moderate |
| 180 or more | Severely hypertensive | High |
Substaging: blood pressure and urine protein
High blood pressure is common in cats with CKD. It can damage the eyes (sudden blindness from a detached retina), the brain, the heart and the kidneys themselves, so it is measured at every check and treated when it stays high.
IRIS also substages by protein in the urine, measured as the urine protein-to-creatinine ratio (UPC). Your vet will tell you which group your cat is in, and you can add the result to that lab panel’s note in FelineSense.
Source: IRIS 2023 · ACVIM Consensus Statement on Systemic Hypertension 2018
In FelineSense
The vet’s plan and every lab panel, in one place
- The IRIS stage exactly as your vet told you. The app never stages the disease itself
- Kidney diet, phosphate binder and sub-Q fluids as prescribed, with a reminder on the fluids interval and a given or skipped log
- Each panel (creatinine, SDMA, phosphorus, blood pressure, urine specific gravity) shown in its IRIS band, with anything above your vet’s stage or phosphorus target flagged to raise with them
- Home signs read from your weight, water and symptom logs: not eating, a 5 % weight loss, vomiting, heavy drinking
- A kidney section in the vet report, and the stage and any fluids due on the Home screen. See all three chronic conditions
Launching first on iPhone and iPad, with Android and Amazon soon after.
Care at home
Living with kidney disease: what helps
The kidney diet
Kidney (renal) diets are lower in phosphorus and moderately restricted in protein, and they are among the best-supported treatments for helping cats with CKD live longer and feel better. Switch slowly, and never while your cat is unwell or in hospital, or they may go off the food for good. If your cat refuses it, tell your vet: eating something matters more than eating the perfect food.
Source: ISFM Feline CKD Guidelines 2016
Water, and fluids under the skin
Cats with CKD lose water through dilute urine, so dehydration is a constant risk. Keep water in several places, try a fountain or wide bowls, and lean on wet food. Some cats also need subcutaneous (sub-Q) fluids at home. Give exactly the volume and interval your vet prescribed; with a calm routine it gets easier for both of you.
Source: ISFM Feline CKD Guidelines 2016
Appetite and nausea
Nausea is common in CKD and treatable, and a poor appetite is often nausea rather than fussiness. A cat with CKD that stops eating for a day needs the vet now: it can go downhill fast and risks fatty liver (hepatic lipidosis). Ask your vet about anti-nausea medicine and appetite stimulants.
Source: ISFM Feline CKD Guidelines 2016
Phosphorus, blood pressure and other medicines
If the diet alone does not bring phosphorus under the target for the stage, your vet may add a phosphate binder mixed into food. Cats with high blood pressure usually need daily medicine and regular rechecks. Never change fluids, diet or medicines without your vet.
Source: IRIS 2023 · ISFM Feline CKD Guidelines 2016
Weigh every week
A drop of 5 % of body weight over two months is worth a call to your vet: the diet, the calories or nausea control may need to change. A baby scale works, or weigh yourself with and without your cat. Water matters too: see how much water a cat should drink, and the other numbers in normal vital signs for a cat.
Not the same thing
Acute kidney injury in cats
Sudden kidney failure is different
Chronic kidney disease builds over months or years. Acute kidney injury happens in days, and in cats the classic causes are poisons. Any part of a true lily or daylily, even pollen groomed off the coat or water from the vase, can cause kidney failure within one to three days. Antifreeze does the same.
Treatment works best before signs appear, so do not wait to see what happens.
Source: ASPCA Animal Poison Control · Cornell Feline Health Center
Already eaten or touched something? Call for advice now.
Your own vet first, or ASPCA Animal Poison Control on (888) 426-4435 — 24/7, a consultation fee may apply. Do not wait for symptoms, and never try to make a cat vomit at home: hydrogen peroxide and salt can badly injure cats. Only a vet can do that safely.
In the app
Weight, water and the record
Questions
Frequently asked
What are the stages of kidney disease in cats?
What are the first signs of kidney disease in cats?
How long can a cat live with kidney disease?
What is SDMA in cats?
Should a cat with kidney disease drink more water?
Does my cat with kidney disease need a special diet?
FelineSense keeps the vet’s stage, the kidney diet, the fluids schedule and every lab panel in one place, and watches weight, appetite, vomiting and water at home.
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