Diabetes mellitus in cats — primarily Type 2 (insulin-resistant) — has become increasingly common, affecting approximately 0.5–1% of the feline population. While requiring lifelong commitment, appropriate management achieves good quality of life and, in many cats, diabetic remission. Understanding the disease and management options supports informed welfare decisions.
Pathophysiology
Feline diabetes involves relative insulin deficiency combined with insulin resistance. Risk factors include obesity, physical inactivity, male sex, older age, and predisposing breeds (Burmese cats are significantly predisposed). Glucocorticoid administration is a common iatrogenic cause. Amyloid deposition in pancreatic islets (similar to Type 2 diabetes in humans) reduces functional beta-cell mass progressively.
Clinical Signs
- Polyuria and polydipsia (PU/PD) — often noticed first as larger, more frequent litter tray use
- Polyphagia (increased appetite) with concurrent weight loss
- Plantigrade stance — characteristic "walking flat-footed" from diabetic neuropathy affecting hindlimb posture
- Poor coat condition and muscle wasting
- Lethargy
Diagnosis
Persistent hyperglycaemia (>14–16 mmol/L) combined with glucosuria confirms diabetes. Fructosamine provides an integrated measure of glycaemic control over the preceding 2–3 weeks. Cats show stress hyperglycaemia easily — single high glucose in a stressed cat is not sufficient for diagnosis without glucosuria.
Treatment
Insulin therapy: Glargine (long-acting) or Prozinc (protamine zinc insulin) are preferred for cats — twice-daily subcutaneous injection. Starting dose is conservative (0.25–0.5 IU/kg BID) with careful monitoring. At-home glucose monitoring (using ear vein lancets and validated cat glucometers) allows dose adjustment without repeated hospital visits.
Diet: Low carbohydrate, high protein diet is critical — wet food (canned) with <10% carbohydrate on dry matter basis. Reducing carbohydrate intake can dramatically improve glycaemic control and facilitate remission.
Diabetic remission: Unique to cats — up to 80% of cats achieving early, tight glycaemic control through low-carbohydrate diet and appropriate insulin can achieve remission (returning to glucose regulation without insulin). Early aggressive management maximises remission likelihood.
Welfare and Monitoring
Hypoglycaemia (excessively low blood glucose from insulin overdose) is the primary acute welfare risk — signs include weakness, wobbliness, and collapse. Owners must recognise and treat with glucose (corn syrup on gums) urgently. Regular veterinary monitoring (fructosamine every 3 months initially), combined with at-home glucose curves and dietary management, enables sustained welfare-positive outcomes in most diabetic cats.