Early Signs of Kidney Disease in Senior Cats (10 Warning Signs)

Increased thirst and increased urination are the earliest reliable signs, and they appear together because they are two halves of the same problem. As the kidneys lose the ability to concentrate urine, more water leaves the body and the cat drinks to compensate. These are usually followed over months by gradual weight loss, a duller coat with less grooming, slightly reduced appetite, and occasional vomiting. Most cats show only two or three of these, arriving gradually enough that each seems unremarkable on its own.

Yes, and this is one of the most important things to understand. Creatinine, the traditional kidney marker, typically does not rise above the normal range until roughly two thirds to three quarters of kidney function has been lost. A cat can have genuine, progressing kidney disease alongside a perfectly normal creatinine. This is why SDMA, which rises earlier, and urine concentration testing are both important. If your cat is showing signs but bloods look normal, ask specifically about SDMA and a urine test instead of accepting the all-clear.

Annual screening from age 7 is the general recommendation, moving to every six to twelve months from 11, and every six months from 15. Each screen should include a blood panel with SDMA, a urine test, a recorded weight, and blood pressure. From around 11, adding a total T4 thyroid test is sensible because hyperthyroidism and kidney disease often occur together and each can mask the other. If your cat is showing any signs, do not wait for the annual appointment.

It varies enormously. Some cats remain stable in an early stage for years with nothing more than a diet change and monitoring, while others progress over months. The main factors influencing the pace are the stage at diagnosis, how well blood phosphorus is controlled, whether protein is being lost in the urine, and whether high blood pressure is identified and treated. This variability is exactly why early detection matters, because the things that slow progression work far better before the damage is advanced.

No, though it always warrants investigation. The three most common causes of increased thirst in senior cats are chronic kidney disease, diabetes mellitus and hyperthyroidism, and all three are identified through a routine senior blood and urine panel. Certain medications, particularly steroids, also increase thirst. What matters is that a persistent, clear increase in drinking is never something to simply watch, because all the likely causes benefit substantially from early treatment.

SDMA stands for symmetric dimethylarginine. It is a kidney marker that tends to rise earlier in the disease course than creatinine, sometimes considerably earlier, and it has the advantage of being less affected by muscle mass. That matters in older cats, who often lose muscle and can therefore have a falsely reassuring creatinine. SDMA is included in most routine senior panels now, but it is worth confirming with your vet instead of assuming, particularly if your cat is showing signs and standard results came back normal.

There is no proven causal link, and it is often overstated online. What is true is that cats have a weak thirst drive and evolved to get most of their water from prey, so cats eating only dry food generally run at lower hydration than those eating wet food. Good hydration supports kidney health throughout life, so including wet food is sensible for that reason. But a cat on dry food is not destined for kidney disease, and a cat on wet food is not protected from it.

The damage itself cannot be reversed, because nephrons do not regenerate. What can be changed is the rate of decline, and that is where early detection earns its value. Phosphorus control through a therapeutic renal diet, treating protein loss in urine, managing blood pressure and maintaining good hydration have all been shown to slow progression. Cats caught in an early stage and managed well frequently live for years with good quality of life, which is a very different outcome from a cat diagnosed at an advanced stage.

Yes. Increased thirst appearing before anything else is the ideal scenario, because it means you have caught a change at the point where treatment is most effective. A cat who otherwise seems well is exactly the cat most likely to be in an early stage. Book a senior panel including SDMA and a urine test. If it comes back clear, you have a valuable baseline to compare against next year, which is worth having in its own right.