It seems as though we are increasingly seeing diabetes mellitus in dogs and cats. Heredity, lifestyle and underlying illnesses can all play a factor. Dogs tend to to develop diabetes from a lack of production of insulin while cats may develop diabetes from a lack of production from damage to the pancreas or insulin resistance.
In dogs, certain breeds have been identified to be at higher risk for developing diabetes. These breeds include keeshond, Alaskan malamute, Australian terrier, beagle, cairn terrier, chow chow, dachshund, Doberman pinscher, English springer spaniel, Finnish spitz, golden retriever, labrador retriever, miniature pinscher, miniature and toy poodles, miniature schnauzer, Old English sheepdog, poodle, pug, samoyed, schipperke, Swedish elkhound, Swedish lapphund, Tibetan terrier, West Highland white terrier (1). Other health conditions such as Cushing's disease may also contribute to the development of diabetes. Long term use of high doses of steroids for other health conditions may also play a role.
For cats and dogs, most require treatment with insulin. Obesity is often a contributing factor, so weight management becomes important in the pet's overall health as well. Especially in cats, many have the potential to reverse their diabetes with initial insulin and weight loss (in cases where obesity is an issue). Diets higher in fiber may help slow the absorption of glucose from the stomach, restricting simple sugars and opting for complex carbohydrates helps prevent the glucose surge that tends to occur after eating a meal. Fat intake should be tailored to calorie requirements.
Insulin is the treatment of choice. Changes in diet may help, but rarely are sufficient to fully control the diabetes. Even cats typically require insulin initially. Over time, they may be able to be controlled with diet alone. This is not the case with most dogs. Insulin supplementation for dogs is usually a life-long need once they develop diabetes. Blood glucose monitors for home use are now available specifically for dogs and cats. For people who have difficulty measuring and administering the insulin injections, there are now insulin "pens" available.
If well regulated, dogs and cats can have a normal life. Dogs do have a high tendency to develop cataracts which lead to blindness. Many dogs adjust well to being blind, but cataract surgery is available through a veterinary ophthalmologist if the dog is stable. Cats may develop diabetic neuropathy where you see them walking with their hocks dropped. I have seen this mostly with cats that are not able to be well regulated.
1. The Genetic Connection, 2nd edition, Lowell Ackerman, DVM, DACVD