Diabetes in cats: management and possible consequences
Introduction
Diabetes can be classified as insulin-dependent (IDDM) or non-insulin-dependent (NIDDM) diabetes mellitus. IDDM is characterised by hypoinsulinaemia, a lack of insulin secretion after glucose administration, the need for treatment with insulin and the tendency to develop ketoacidosis. Diabetes has a multifactorial aetiology that is influenced by genetics, breed, immune-mediated factors, acute pancreatitis (rare) and amyloid deposition in islet cells (which is relatively common in cats).
NIDDM is characterised by normal/high insulin levels, exaggerated insulin secretion following glucose administration and obesity that causes a poor peripheral insulin response, which is a particularly common finding in obese cats. This insulin antagonism develops in obese individuals because of their state of hyperinsulinaemia.
Thirdly, diabetes may be brought on by an excess of diabetogenic substances that are either derived from exogenously administered drugs (corticosteroids, progesterone) or produced at higher levels in certain concomitant diseases (hyperadrenocorticism, acromegaly), with characteristics similar to NIDDM.
Clinical implications
Diabetes in cats can affect animals of all ages, but predominantly those over 6 years and with a greater predisposition in males.
Depending on the disease’s severity and progression, the clinical signs range from mild, such as weight loss, to very serious clinical conditions such as diabetic ketoacidosis or hyperosmolar coma.
The signs of diabetes in cats include:
- Polyuria/polydipsia (for more information on other causes of polydipsia, click here)
- Weight loss with polyphagia
- Changes in the coat
- Bad breath
- Cataracts. While this is the leading complication in dogs, it is very rare in cats
- Diabetic neuropathy
- Hepatic steatosis with hepatomegaly
- Urinary tract infection with signs such as haematuria
- Signs of ketoacidosis and hyperosmolar coma: dehydration, weakness, tachypnoea, vomiting, acetone-like smell, hypothermia and coma
As stated above, obesity is the main risk factor for developing NIDDM, and it is one of the most frequent nutritional disorders in cats. Recent studies have shown that the incidence of obesity or excess body weight (BW) in cats ranges from 17 to 52%. The simplest clinical method for assessing a cat’s degree of underweight or obesity is to evaluate its body condition (BC) using a 5‑point scale where a score of 3 represents an optimal body condition. A score of 3 roughly equates to 22 ± 2% body fat. The main risk factors are old age, male and castration.
The latest evidence suggests that an increase in oxidative stress due to the accumulation of adipocytes creates a proinflammatory state in obese cats known as metabolic syndrome. This inflammatory state could explain the decline in insulin sensitivity observed in castrated and obese male cats.
Dietary recommendations
Researchers have shown that weight loss normalises insulin sensitivity in obese cats, so most cases of diabetes in cats do not need to be managed with insulin.
The key, therefore, is to establish a weight loss plan that aims to increase caloric expenditure besides changing the patient’s dietary habits. A well adapted weight loss diet generally features an energy restriction of 20–30%, a high-protein, low-fat content, natural sources of fibre and a balanced nutrient profile. The addition of a metabolic booster in the form of citrus flavonoid supplementation has produced significant improvements in oxidative stress markers and inflammatory markers and improvements in the lipid profile. Finally, it is important to stimulate the cat’s natural behavioural instincts and encourage physical activity.
