How long can a dog or cat live with diabetes?

Quick answer

A diabetes diagnosis is not a death sentence — and we are not going to give you a lifespan figure, because nobody honestly has one for a treated pet.

What exists are UK primary-care records covering every diagnosed animal, treated or not. They tell you what happens to diabetic pets as a population. They do not tell you what happens to yours, and the difference between those two things is most of this page.

What the UK figures actually say

Dogs. The largest UK study of dogs in ordinary practice found a median survival from diagnosis of 15.6 months, rising to 20.2 months among dogs who survived the first week. Around 62% had died by the end of the study, and 92.5% of those deaths were by euthanasia.

Cats. The largest UK study, covering over 1.2 million cats, found a median time to death after diagnosis of 68 days — with an enormous spread, the middle half falling between 9 days and just under a year. Of the cats who died within three years, 93% were euthanased, and around one cat in ten was euthanased within three days of diagnosis, most of them without being treated at all.

Those are lower than almost every figure you will find elsewhere, including the ones this page used to carry. We could not source those, so they are gone.

Why those numbers are about decisions as much as disease

Read the euthanasia proportions again. These are not measurements of how long the illness lets an animal live. They are measurements of what happens after a diagnosis in the real world, where some owners start treatment, some cannot afford to, and some decide not to.

The same canine study found the thing worth taking from all of it: dogs started on insulin had a hazard of death roughly a twelfth of those who were not. The medians are low because of what happens in the first few days, not because treatment fails.

So if your pet has been diagnosed and you are treating them, the population median is not your number. It was never going to be.

What actually moves it

In rough order of how much difference they make:

1. Starting treatment, and continuing it. Nothing else on this list is close.
2. Getting through the first few months. This is the risky stretch, while the dose is being established and you are learning the routine. Pets that come out of stabilisation generally do well.
3. Catching the two emergencies early. Low blood sugar and ketones building up are what turn a managed condition into a crisis, and both are survivable when caught.
4. A routine you can actually keep up. The best plan is the one still running in month eight. A regime that collapses after a fortnight is worse than a simpler one that holds.
5. Keeping the record. Not because writing things down treats anything, but because dose decisions are made on patterns, and a vet working from memory is working from less.

That last one is what the Mello app is for: what was given, when, and by whom. It does not calculate or suggest a dose, and it never will.

Remission

Cats. A minority, not a majority. The 2026 AAHA guidelines work to an average of around 30%; published rates range from 11% to over 60% depending on the population and how hard remission was pursued. Roughly a quarter of the cats who reach it do so within two to three months of diagnosis and most of the rest within six — so the first half-year is the window.

It is not a cure. The current consensus puts the median length of remission at about four to five months, with 13% to 40% of cats relapsing, and a second remission is generally less likely than the first. Remission is associated with longer survival. See diabetic remission in cats.

Dogs. Plan for insulin for life. Canine diabetes is generally lifelong because it usually involves a loss of insulin production rather than resistance to it. The one real exception is an entire bitch whose diabetes was driven by the hormones of her season — spaying is recommended there and can allow it to resolve, which is why your vet will ask whether she is neutered.

The complication that most changes the picture

Cataracts are the one most owners are unprepared for. They affect over 85% of diabetic dogs, they can develop within days, and — this is the part worth knowing in advance — specialist ophthalmology guidance is explicit that they occur regardless of how well the diabetes is regulated. A cataract is not evidence that you have managed things badly.

Surgery is often possible and usually successful. Ask about referral early, because results are better before the eye becomes inflamed. Costs vary widely between UK practices, so ask for a written estimate rather than trusting a figure from the internet. Cats rarely develop them.

Other conditions change the picture too — pancreatitis and diabetes often occur together in dogs, and urinary infections, neuropathy in cats and kidney disease all come up.

On quality of life

Most diabetic pets, once the routine is established, carry on being themselves: walks, play, company, food they enjoy. What changes is the structure around them rather than the life inside it.

When that stops being true, lifespan is the wrong measure, and that is a conversation to have with your vet rather than a table to read. We have written separately about quality of life and the difficult decisions, including what to watch for and how vets approach it.

Sources

The pages below were each opened and checked before being listed here, and anything that could not be opened was left off rather than guessed at.

• Diabetes mellitus in dogs attending UK primary-care practices: frequency, risk factors and survival — Canine Medicine and Genetics 7:6, via the RVC repository, 2020. Every canine figure on this page: median survival of 15.6 months from diagnosis, 20.2 months among dogs surviving the first week, 92.5% of deaths by euthanasia, and the far lower hazard of death in dogs started on insulin.
• Frequency, Risk Factors and Mortality for Diabetes Mellitus in 1,225,130 Cats Under Primary Veterinary Care in the UK — Journal of Veterinary Internal Medicine 39(4), 2025. The feline figures: a median of 68 days to death after diagnosis with a very wide spread, 93% of those deaths by euthanasia, and roughly one cat in ten euthanased within three days, most untreated.
• Diabetic Remission (Section 9) — 2026 AAHA Diabetes Management Guidelines for Cats, 2026. The remission rate used here — around 30% on the current task-force figure — and the timing of when cats reach it.
• 2025 iCatCare consensus guidelines on the diagnosis and management of diabetes mellitus in cats — Journal of Feline Medicine and Surgery 27:1–37, 2025. How long remission lasts, with a median of about four to five months, and relapse in 13% to 40%.
• The Lens in Animals — MSD Veterinary Manual, Ralph E. Hamor DVM MS DACVO, reviewed February 2023, updated July 2026. The cataract figures, including that they occur in over 85% of diabetic dogs regardless of how well the diabetes is regulated.
• Diabetes Mellitus in Dogs and Cats — MSD Veterinary Manual, reviewed May 2024, updated May 2026. That canine diabetes is generally lifelong, and that spaying is recommended in intact diabetic bitches.