Diabetes mellitus is a condition that develops when the body is not capable of producing enough insulin or cannot respond to it the way it should - even if the production of insulin is sufficient. Insulin is a hormone that allows the body to take in glucose for energy and it is produced by the pancreas' islet cells. The most common cause of diabetes is damage or destruction of these cells, although there is no definite reason as to why this happens.

Similar to the disease in dogs, diabetes can affect cats of any age, breed or gender. However, unlike dogs, the typical diabetic cat is often older (6+ years of age), overweight, and the condition is more common in neutered males. 


Many diabetic cats remain bright, alert, and outwardly normal. The most common sign noticed by owners is a change in the cat’s behavior - specifically, a dramatic increase in thirst (drinking water) and hunger (ravenous appetite). Although not as common, some cats may show a decrease in their appetite. As is seen in diabetic dogs, the cat may urinate more frequently and produce more urine than normal.

Something that can be unique to the diabetic cat (compared to affected dogs) is the significant change in their hair coat. Their coat may become dull, oily and develop flakes or "dandruff." They may also develop loss of muscle mass, most notably along their back and rear legs.

Although diabetic dogs often develop cataracts, cats do not. Unique to cats, however, is that they may begin to walk flat-footed on their hind feet rather than up on their toes. This is due to nerve damage (diabetic neuropathy), caused by prolonged hyperglycemia (high blood sugar). 

If the diabetes goes untreated or uncontrolled for too long, the cat can go into a state of ketoacidosis and become critically ill, needing immediate medical attention. In this case, the cat will appear depressed and weak, become dehydrated, and, in extreme cases, fall into a coma. It is extremely important to be aware of signs of diabetes in the cat.

In summary, the signs and symptoms of diabetes include:

  • Increase in thirst
  • Increase in hunger (sometimes decrease)
  • Increased urination
  • Dull, oily, flaky hair coat
  • Muscle loss along the back and hind legs
  • Flat-footedness in hind legs
  • Ketoacidosis (depression, weakness, dehydration, coma)


Diagnosing diabetes in the cat is similar to diagnosing it in the dog. A simple test is performed to measure the amount of glucose in the blood and/or urine. Normal blood-glucose levels for cats can range from 80-120 mg/dL. If a cat has diabetes, their blood-glucose levels will be significantly increased.  One notable difference between cats and dogs, is that cats are prone to developing high blood-glucose levels when stressed. Repeated blood glucose measurements may be required to help differentiate diabetes from a stress response. Other tests, such as the fructosamine test, can be done to help determine if increases in the cat’s blood-glucose levels are likely caused by diabetes, or simply from being stressed.

A serious form or complication of uncontrolled diabetes is a condition termed diabetic ketoacidosis (DKA). In these cases, there are are other changes in the blood and urine that point to this serious metabolic disorder.


Treating the diabetic cat is very similar to dogs and involves the daily administration of insulin. Cats tend to metabolize insulin more quickly and are often treated with longer-acting insulin products. In cats whose diabetes is linked to obesity, dietary changes and weight loss may decrease the need for insulin. Your veterinarian may prescribe or suggest a high protein, low carb diet in these cases.

Periodic monitoring of blood glucose levels (blood glucose curves) may be required to fine tune the appropriate dosage and frequency of insulin administration in the diabetic patient. The goal is to determine the proper dose and frequency of administration to keep the blood glucose levels within the normal range - not too high and not too low.


Properly regulating the diabetic cat can be challenging, however in some instances, cats that experience good control early on in the course of the disease may actually achieve remission. Every cat responds to insulin differently, and one of the challenges in treating cats is determining the amount of insulin that keeps blood glucose levels with the normal range, and not dropping it too low (hypoglycemia). Hypoglycemia, if not treated, can be life threatening.

The outcome for diabetic pet is dependent on a team's effort. With the right tools and the help of your veterinarian, your cat can lead a happy, normal life with the care you provide.