Understanding Diabetes in Cats
Diabetes mellitus is a condition in which the body is unable to regulate blood glucose effectively, either because the pancreas produces insufficient insulin or because the body's cells fail to respond to it properly. In cats, the vast majority of cases are analogous to type 2 diabetes in humans — the pancreatic beta cells are initially capable of producing insulin, but peripheral insulin resistance (often driven by obesity) gradually overwhelms the system. Over time, prolonged overwork and glucose toxicity damage the beta cells themselves, further reducing insulin output.
The condition is increasingly common in domestic cats, driven in large part by rising rates of obesity, sedentary indoor lifestyles, and diets high in carbohydrates. Understanding the risk factors, recognising the signs early, and engaging proactively with treatment gives affected cats the best possible prognosis — including a genuine chance of remission.
Risk Factors
Certain cats are at higher risk of developing diabetes mellitus:
- Obesity: The single most significant modifiable risk factor. Obese cats are four times more likely to develop diabetes than lean cats.
- Neutered male cats: Male cats have a higher prevalence than females.
- Indoor, sedentary lifestyle: Reduced physical activity promotes insulin resistance.
- Middle-aged to older cats: Diabetes is most common in cats aged seven and above.
- Breed predisposition: Burmese cats have a well-documented genetic predisposition to diabetes mellitus, particularly in Australia and the UK, and should be monitored closely as they age.
- Long-term corticosteroid use and concurrent hyperthyroidism can both precipitate or exacerbate insulin resistance.
Clinical Signs of Diabetes in Cats
The classical signs of feline diabetes are highly recognisable once you know what to look for:
- Polyuria and polydipsia (PU/PD): The hallmark presenting signs — large volumes of very pale, dilute urine and markedly increased water intake. Owners may notice a litter tray filling unusually quickly.
- Weight loss despite increased appetite (polyphagia): Because cells cannot access glucose effectively, the body breaks down fat and muscle for energy. The cat eats more but loses condition steadily.
- Plantigrade stance: A characteristic sign in diabetic cats — the hocks drop to the ground during walking, giving the appearance of walking flat on the lower leg rather than on the toes. This results from diabetic neuropathy affecting the peripheral nerves.
- Lethargy and reduced activity
- Unkempt coat
- Muscle wasting, particularly over the hindquarters and spine
Diagnosis
Diagnosis requires demonstration of persistent hyperglycaemia (elevated blood glucose) alongside glucosuria (glucose in the urine). A single blood glucose reading can be misleading in cats — stress alone can cause transient hyperglycaemia (stress hyperglycaemia) that mimics diabetes. This is why fructosamine measurement is so useful in feline medicine: fructosamine reflects average blood glucose levels over the preceding two to three weeks and is not affected by acute stress. An elevated fructosamine alongside hyperglycaemia and compatible clinical signs confirms the diagnosis.
A full blood panel and urinalysis are performed at diagnosis to exclude concurrent conditions — particularly urinary tract infection (common in diabetic cats due to glucose in the urine providing a bacterial substrate), hyperthyroidism, pancreatitis, and CKD. ECVIM-CA and WSAVA guidelines both recommend comprehensive baseline testing before initiating insulin therapy, as concurrent diseases influence treatment decisions significantly.
Insulin Therapy in the EU
Most diabetic cats require insulin injections, administered subcutaneously (under the skin) by the owner at home — twice daily in most protocols. This is far less daunting in practice than it sounds; cats generally tolerate injections very well, and owners typically become confident within a few days with veterinary guidance.
Several insulin preparations are licensed or commonly used in EU cats:
- Caninsulin (porcine lente insulin): Licensed for dogs and cats across the EU; intermediate-acting and twice-daily dosing is standard in cats.
- ProZinc (protamine zinc insulin): Licensed specifically for cats in the EU and USA; long-acting, designed for once or twice-daily use.
- Glargine (Lantus): A long-acting human insulin analogue that has become increasingly popular in veterinary practice for cats, particularly because of its association with higher rates of diabetic remission when used alongside a low-carbohydrate diet. Not licensed for veterinary use but widely used off-licence in EU clinical practice.
Dose adjustments are guided by glucose curves (blood glucose measured at multiple time points over a day) and fructosamine monitoring.
Diet: The Key to Remission
Dietary management is arguably as important as insulin therapy in feline diabetes. Cats are obligate carnivores with a metabolic requirement for protein and a very limited capacity to regulate carbohydrate metabolism. A low-carbohydrate, high-protein diet — typically a wet food rather than dry kibble — reduces postprandial glucose spikes and, in combination with appropriate insulin, significantly increases the likelihood of diabetic remission.
Remission — defined as the cat maintaining normal blood glucose without ongoing insulin therapy — is achievable in around 50-80% of newly diagnosed cats treated with glargine or detemir insulin alongside a strict low-carbohydrate diet. Early diagnosis and swift glucose regulation give the best chance of allowing damaged beta cells to recover.
Zooplus stocks a wide range of diabetic-appropriate cat foods, including prescription diabetic diets from Royal Canin, Hill's m/d, and Specific, as well as a broad selection of high-protein wet foods that can form part of a vet-approved feeding plan. Your veterinary team will help you identify the most suitable option for your cat's individual needs and preferences.
Home Glucose Monitoring
Home blood glucose monitoring — using a small hand-held glucometer and a tiny sample from the ear margin or paw pad — is increasingly recommended by specialist internal medicine vets and endorsed in ECVIM-CA guidelines. It gives owners far more data than periodic clinic visits alone and allows much tighter glucose regulation, which in turn improves remission rates and reduces the risk of hypoglycaemia. Many owners initially hesitant about home monitoring become confident and skilled within a few weeks.
Diabetic Ketoacidosis: A Life-Threatening Emergency
Diabetic ketoacidosis (DKA) is a severe, acute complication that occurs when the body, deprived of glucose access, breaks down fat at a rate that overwhelms the liver's capacity to process ketone bodies. DKA develops most commonly in undiagnosed or poorly regulated diabetic cats and carries a serious risk of death without emergency treatment. Signs of DKA include:
- Vomiting and profound lethargy
- Complete anorexia
- Dehydration and weakness
- A sweet or acetone-like smell to the breath
- Rapid or laboured breathing
- Collapse
When to Seek Urgent Care
Contact your vet immediately or go to an emergency clinic if your cat:
- Shows any signs of DKA listed above
- Becomes suddenly weak, wobbly, or unresponsive (possible hypoglycaemia from too much insulin)
- Refuses food for more than 24 hours while on insulin
- Has a seizure
Hypoglycaemia (blood glucose falling too low) is a medical emergency — if suspected, rub a small amount of glucose gel or honey onto the gums and seek emergency veterinary care immediately.
This article was written by Sarah Bennett. Always consult a registered veterinary surgeon for advice specific to your pet.