Diabetes in Cats
Written by Shula Berg BVSc CertAVP(GSAS) GPAdvCert(SASTS) MRCVS
Clinically reviewed by Elizabeth McLennan-Green BVM&S CertAVP(SAM) MRCVS
Table of Contents
Diabetes causes levels of glucose (sugar) in the blood to be persistently high. When blood glucose levels increase, the pancreas releases a hormone called insulin. This tells the body to excrete more glucose until levels return to normal. In most cases of feline diabetes, the pancreas does not make enough insulin, and the body does not respond to insulin properly. This lack of response is known as insulin resistance and is like type 2 diabetes in people.
Any cat can develop diabetes; however, it is most common in cats over ten years old, with more males affected than females. Indoor cats, those leading very sedentary lifestyles, and overweight cats are at increased risk of developing diabetes.
The most common symptoms of diabetes are increased thirst and urination, weight loss, and appetite changes. Initially, an increased appetite can be seen, however, as cats become more unwell, appetite often decreases. Weight loss is a common feature though many cats are still overweight at the time of diagnosis.
Persistently high blood sugar can cause nerve damage, seen as weakness, wobbly gait and difficulty jumping. This is known as peripheral neuropathy and can occur in up to 50% of diabetic cats. If not caught early, some cats may become dull and dehydrated.
A thorough history and clinical examination will often raise a strong suspicion of diabetes. Stress, such as having a blood sample taken, can cause high glucose levels in cats, and a single high glucose reading is not enough to confirm diabetes. Several tests are therefore used in combination to confirm the diagnosis and guide treatment:
General blood tests
These will measure blood glucose as well as checking the liver, kidneys, protein levels, and blood cells. They screen for other conditions that can cause similar symptoms to diabetes or occur at the same time.
Diabetic cats will have high levels of glucose in their urine. Diabetic cats are prone to urinary tract infections so your vet may advise taking a urine sample directly from the bladder (known as cystocentesis) for culture, to identify bacteria.
Concentration of the protein fructosamine reflects glucose levels over the previous two weeks. It is less reliable in cats than in dogs but can be helpful to confirm a diagnosis. Fructosamine is measured at an external lab, so treatment is sometimes started before results are available, especially in unwell animals.
Diabetes is generally treated by injecting insulin twice daily. This needs to be done every day for as long as the cat requires treatment. It is important that both mealtimes and insulin injections are regular, and that all family members who look after the cat understand the treatment required. Excitingly, a new treatment option for feline diabetes, Velaglifozin, became available in November 2023. This treatment is a once-daily oral treatment that is proving very effective in some cases. It is not suitable for every cat, however, so after diagnosis your vet will discuss the most appropriate treatment option for your cat.
Cats who are bright and well at diagnosis can often be managed as an outpatient. Cats who are unwell, especially if dehydrated and/or not eating, often need hospitalisation. It is more challenging to stabilise a cat who is not eating at the time of diagnosis, and as a result, it is not uncommon that unwell cats remain in hospital for 4-7 days after diagnosis. Some cats will require a temporary feeding tube to be placed whilst hospitalised.
Diabetes in cats has a reasonable to good prognosis, with most cats responding well to treatment. If glucose levels are controlled effectively for a long period, some cats will regain the ability to produce and respond to insulin. This can mean less medication needs to be administered or, for some cats, treatment can be stopped all together. Sometimes the condition can be managed with a specific diet protocol. This is known as diabetic remission and can occur in up to 80% of cats started on treatment promptly after diagnosis. Cats can stay in remission indefinitely, although roughly 1 in 4 will relapse and require regular medication administration again.
Cats who have more severe symptoms at the time of diagnosis, or have concurrent diseases, have a more guarded prognosis and are less likely to achieve remission. Even well controlled diabetics can have changing response to medication over time and are at risk of becoming unstable. It is not uncommon for diabetics to require occasional periods of hospitalisation during their lives, as simple conditions such as gastrointestinal upset can disrupt glucose control.
It is important to emphasise that treatment of diabetes can be lifelong and can therefore be both costly and time-consuming. Although not essential, it is easier if diabetic cats are kept indoors (especially if they roam and don’t return home regularly) to ensure they receive their medication at the correct time. Dietary changes may also be needed.
Please note that the content made available on this webpage is for general information purposes only. Whilst we try to ensure that at the time of writing all material is up to date and reflects industry standards, we make no representation, warranties or guarantees that the information made available is up to date, accurate or complete. Any reliance placed by yourselves is done so at your own risk.
Page last reviewed: 16th January 2024
Next review due: 16th January 2026