Diabetes melliitus (DM) is commonly seen in dogs and cats. This condition develops when the body is not capable of producing enough insulin or when the body cannot respond to insulin in a normal fashion. Insulin is a hormone that allows the cells of the body to take in glucose for energy. The most common cause of diabetes is damage or destruction of cells in the pancreas. Diabetic patients, because of their insufficient insulin production, usually have hyperglycemia (high blood sugar) and glucose in their urine. This condition is a usually a chronic, life-long disease.

Although the disease can affect both cats and dogs, there are species-specific differences for certain known risk factors and for how the disease manifests. Some of these differences include:

  • Obesity is an important risk factor for DM in cats (but not for dogs)
  • Cats can experience diabetic remission, however this is uncommonly seen in dogs
  • Other disorders are often associated with the development of DM in cats (hyperadrenocorticism (Cushing's Syndrome), hypersomatotropism)
  • Diabetic cataracts commonly develop in dogs but not in cats with DM
  • Neuropathy associated with diabetes is more commonly seen in cats than in dogs


The approach to long-term management of patients is multimodal and includes weight control, exercise, diets higher in fiber / lower in complex carbohydrates, and daily insulin administration.

There are a variety of insulin types available for use, and these types are typically categorized based on their absorption time / rapidity of effect and duration of effect (short-, intermediate-, and long-acting insulins).

Synthetic insulins are relatively newer options available to veterinarians for treating patients. They are modified forms of insulin and they are commonly used in humans due to their long-acting effect. Insulin glargine is one such insulin analog; its use has also been described in dogs and cats with diabetes mellitus.


Both species can develop a severe form of diabetes mellitus - diabetic ketoacidosis (DKA) - in which there is an excessive accumulation of ketones in their body. Ketones are derived from free fatty acids that are normally released from fat tissue. These free fatty acids are taken up by the liver and can then be metabolized by the liver, incorporated into triglycerides, or they can undergo oxidation which leads to their conversion into ketones. Normally, ketones are then utilized by tissues as an energy source in a period of glucose deprivation. However, in the patient with uncontrolled diabetes mellitus (a physiologic state of starvation), there is an excess production of ketone bodies which results in the development of ketosis and acidosis which can be life-threatening.

Patients with DKA require emergent care to stabilize the life-threatening metabolic changes including metabolic acidosis, severe electrolyte imbalances (low sodium, potassium, chloride), and the presence of ketones in the blood or urine.

Learn more on causes, diagnosis, treatment, and prognosis of Diabetes Mellitus in Dogs & Diabetes Mellitus in Cats