The Diabetic Cat

Written on July 31, 2013 by Heidi L. White, DVM, DACVIM Hospital: Massachusetts Veterinary Referral Hospital

Diabetes Mellitus

Emmitt Diabetes mellitus has a reported frequency of approximately 1:250 for both dogs and cats.  It occurs in cats when the pancreas is not making enough insulin.  Insulin is what is required for sugar to move from the blood into the cells.  Without insulin the body feels as if it is starving even though there is a lot of sugar in the blood.  The sugar in the blood is so high it overwhelms the kidneys and spills into the urine.  The sugar in the urine also pulls water with it.

The clinical signs of diabetes are:

  • excessive eating with weight loss,
  • excessive drinking
  • excessive urination.

Middle aged to older cats that are overweight and cats on steroids for other medical conditions are more likely to become diabetic.


The diagnosis is made by having a high blood sugar for more than one reading and sugar in the urine.  Cats are also prone to having a high blood sugar level as a result of stress so sometimes a blood test called a fructosamine is needed for diagnosis.  This test looks at what the blood sugar has been on average over the past several weeks.



Diabetes mellitus in cats is treated with twice daily injections of insulin.   A high protein diet is also important. Approximately 20% of diabetic cats can be transient diabetics, meaning after 4-6 weeks of initiation of treatment, they are no longer diabetics.  Once a cat is regulated on insulin the owner should notice that the clinical signs of excessive drinking and urination have improved.

Your family veterinarian can monitor the diabetes with an 8 hour glucose curve where the blood sugar is checked every 2 hours, or owners can check their own cat’s blood sugars at home by performing ear pricks and using a glucometer.  Depending on the readings, the pet owner will work with his or her veterinarian to adjust the insulin dose, or type, as needed.


The prognosis for diabetic cats depends in part on the owner’s commitment to treat, and the presence of concurrent disorders.

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