While diabetes affects people and pets, the impacts of the disease vary across species. We asked Dr. Bruyette about the differences in type, symptoms, treatments, and research between diabetic humans and animals.
What does diabetes look like in dogs and cats?
Diabetes mellitus is a common disease in dogs and cats occurring in about 1:30 to 1:40 pets. The most common form of diabetes in dogs resembles type 1 diabetes in humans, sometimes referred to as insulin dependent. Studies suggest that genetics, an immune-mediated component, and environmental factors are involved in the development of diabetes in dogs. A variant of gestational diabetes also occurs in dogs.
The most common form of diabetes in cats resembles type 2 diabetes in humans, which is non-insulin dependent. A major risk factor in cats is obesity. Obese cats have altered expression of several insulin signaling genes and glucose transporters and are leptin resistant. Cats also form amyloid deposits within the islets of the pancreas and develop glucotoxicity when exposed to prolonged hyperglycemia.
How does diabetes differ across the species? What are similarities?
Diabetes is similar across species as the end result of the disease. Too little insulin and too much glucose is common to all patients. What is different is the approach to controlling blood sugar levels which is much more demanding/aggressive in man than in animals.
What are common misconceptions about diabetes in animals versus in humans?
One of the common misconceptions is that pets with diabetes will exhibit all the complications of diabetes known to occur in man: Loss of vision from diabetic retinopathy, kidney failure from diabetic nephropathy, stroke and heart attack from large vessel disease, and the risk of amputation from small vessel disease, weakness and pain from diabetic neuropathy.
None of these occur in pets, not because diabetes behaves differently, but because these complications occur over decades in man. While vision loss or impairment can occur in dogs as a result of diabetes induced cataracts, which are very rare in cats, they can be successfully treated with surgery.
In order to prevent these complications in man, very tight control of blood glucose is required resulting in patients having to take insulin and oral diabetes medications multiple times a day along with multiple daily measurements of their blood glucose.
However, in pets, our goals are much easier to attain. Our goals are to lower the blood glucose sufficiently to prevent or lessen the common clinical signs of diabetes, which are excessive drinking and urination, slow or delay the progression of cataracts, preserve ideal body weight as both obesity and being too thin can complicate management, and prevent hypoglycemic reactions.
How does research and advancement of veterinary medicine differ from that of human healthcare?
Generally, advances can occur more quickly in the veterinary space given the large number of patients affected and the shorter life spans of dogs and cats. This makes them ideal candidates to evaluate therapies as they move from small animal models, including rats and mice, to large animal models, including dogs, cats and primates, into man. The cost associated with this translational approach are also much less in the veterinary space.
The similarities in diabetes across species.
Diabetes across species shares the commonality of not enough insulin and too much glucose. Because of the differing lifespan and genetic makeup of each species, humans, cats, and dogs, each have differing health complications and treatments for diabetes. Advances in the veterinary space regarding diabetes research may be beneficial to those in the human medicine field.