Diabetes in cats can lead to weight loss, vomiting, dehydration, and even death.
cat drinking out of water bowl
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Just as diabetes requires attention in humans, diabetes in cats can significantly affect your darling pet's life. You can manage the condition, but most diabetic cats need daily long-term care. There's no easy one-time fix for cat diabetes.

Diabetes mellitus is one of the most common endocrine disorders in cats. It occurs when a cat's body either doesn't make insulin or doesn't make enough insulin. 

What Causes Diabetes in Cats?

Leah Cohn, DVM, Ph.D., DACVIM, an internal medicine specialist and professor at the University of Missouri College of Veterinary Medicine in Columbia, Mo., refers to diabetes mellitus as "sugar-related diabetes." It occurs when too much glucose (sugar) is circulating in the bloodstream due to a problem with the body's production of or response to the hormone insulin, she says. 

Cells need insulin to be able to take in glucose and convert it into energy. This in turn helps regulate how much glucose is in the bloodstream. When the body doesn't have enough insulin, the glucose in the blood can't be used for energy and the body must turn to other sources, such as fats and proteins, to survive. 

Similar to humans, there is Type I and Type II diabetes in cats:

  • With Type I diabetes, the cat's body simply doesn't make insulin. Cohn says that this is usually because the cat's immune system has attacked and destroyed the cells in the pancreas that make insulin.
  • A cat with Type II diabetes can still make insulin, Cohn says, but not enough. Your cat either can't produce normal amounts, or the body needs more than usual because it's become resistant to insulin. 

Which Cats Are Most at Risk?

According to Cohn, risk factors for feline diabetes include:

  • Age. Diabetes mellitus is generally seen in middle-aged and older adult cats. 
  • Obesity. "Obese cats have greater insulin requirements," Cohn says, "and are more likely to be resistant to insulin and have Type II diabetes." However, she notes that not all cats with Type II diabetes are overweight.
  • Steroid therapy. "Cats given systemic steroids for a long period of time are more likely to develop diabetes because it can cause insulin resistance," Cohn says. 
  • Other disorders. The American Association of Feline Practitioners (AAFP) notes that cats diagnosed with pancreatic disease, hyperthyroidism, renal disease, neoplasia, acromegaly, and hyperadrenocorticism are at a higher risk for developing diabetes

What Are the Signs of Diabetes in Cats?

Cohn says cats with diabetes may exhibit these signs: 

  • Weight loss. Your cat may lose weight despite eating well, she says. Without insulin, your pet's body has to break down other sources of energy, like fat. So while she may be obese when she develops diabetes, Cohn says your cat will eventually lose weight. 
  • Increased drinking and urination. You may notice that the litter box has to be changed more frequently and that it's heavier and wetter than usual, Cohn says. Extra sugar in the blood leads to extra sugar in the urine. "Sugar draws water into the urine—a process called osmotic diuresis—which can increase urine volume and cause cats to have to drink more water to keep up."
  • Plantigrade stance. This is a fancy way of saying that your cat starts walking on her heels, or hocks—a condition caused by nerve damage, Cohn says.

Cats can sometimes develop a complication called diabetic ketoacidosis, but this only occurs in those that have been diabetic for a while but no one's noticed the signs. "This is probably the worst case scenario," Cohn says. "Cats with diabetic ketoacidosis are very, very sick (e.g. vomiting, extremely lethargic, may collapse) and can die."

What Should You Expect at the Vet?

Diagnosing diabetes involves testing glucose levels in your cat's blood and urine. A healthy animal's urine won't contain glucose, and the amount of glucose in the blood will be at a normal level. But in diabetic cats, the urine will contain sugar, and blood glucose will be higher than it should be. 

Though this may seem like a straightforward process, Cohn says that the nature of cats can complicate diagnosis. "Cats who are scared or upset, as might be the case if they're put in a carrier and taken to a veterinary hospital, can have a temporary spike in blood glucose due to an adrenaline response," she says. "So if the glucose is up higher than normal when tested but not sky high, the veterinarian may be unsure if it's due to the stress of the event or diabetes." 

In such cases, your cat may have to be evaluated at a different time, or you may be asked to collect urine at home (where the cat is more at ease). Your veterinarian might also perform a blood test that must be sent off to a laboratory to confirm whether diabetes or stress is causing the spike. 

What Are the Treatments for Feline Diabetes?

If your cat is diagnosed with diabetes, your veterinarian will work with you to create a treatment plan, which usually involves a combination of diet and insulin therapy. 

Diet. Because obesity is a risk factor for diabetes, it's important that overweight diabetic cats get to an ideal body weight. Your veterinarian can help you determine the ideal weight for your cat and develop a plan for reaching it. Because cats with diabetes tend to benefit from a diet that's low in carbohydrates, your veterinarian will likely recommend a high-protein, low-carbohydrate food. Usually a canned food diet, both prescription and over-the-counter options are available, Cohn says.  

Insulin therapy. Most diabetic cats will need two insulin injections a day. "It sounds kind of scary at first," Cohn says, "but I tell owners that it's far easier to give a cat an injection than a pill." If you feed your cat at the same time you deliver the insulin, there's a good chance he won't even notice, she says. Plus, the needle is tiny. "It's much smaller than what we use for vaccinations," Cohn says. "Cats may not even realize they're getting an injection." Still, you should let your vet know if you feel uncomfortable. Cohn says your vet can help you get used to handling the needle by having you practice injecting water into a piece of fruit. 

Your veterinarian will also teach you how to properly handle and store insulin, monitor blood glucose, and recognize the signs of hypoglycemia (which can happen if your cat gets too much insulin). 

Your vet may also recommend keeping a daily treatment log for your cat, which should include the insulin dose and the time you gave it, as well as notes on food and water intake, urine output, and any changes you notice. These records will make it easier for you and your vet to adjust the treatment plan to your cat's needs.

"If treatment goes well and we're able to achieve good blood glucose regulation, cats with diabetes can live a pretty normal life," Cohn says. Some cats with Type II diabetes even go into remission for a period of time that can last one to two years or the rest of their lives. 

Is Diabetes in Cats Expensive to Treat?

"There's just no getting around it," Cohn says. "The costs of treating feline diabetes are not insignificant." 

Four types of insulin are commonly used to treat cats with diabetes mellitus, she says. Two are veterinary formulations, and two are from human medicine. "The insulin that's preferred by most veterinarians is one that's made for humans, and the price has shot up over the last decade," Cohn says. "The good news is that one bottle of insulin can last multiple months when treating a cat. It's meant to be used for a month and is marked that way for use in people, but it will stay good with appropriate handling and storage for much longer." 

The costs associated with diabetes treatment go beyond insulin. Repeat veterinary appointments, blood glucose monitoring, special foods, and syringes should be factored in.

Can Feline Diabetes Be Prevented?

There's no way to absolutely prevent your cat from developing diabetes, according to Cohn. "Keeping your cat at a healthy weight is the best thing you can do," she says. "And if your cat needs to be on steroids, educating yourself about the signs of diabetes can help you catch the condition early." 

Talk to your vet if you see any signs that your cat has developed diabetes. Your vet can diagnose the problem accurately and help you decide on an effective treatment plan for your precious pet.