Tight or loose glycemic control? What’s the right choice for your diabetic felines?


In this age of consumer choice, pet owners expect medical care personalized to their cat’s unique needs and their personal lifestyle.

Clients vary in their awareness of feline diabetes: some have no knowledge of feline diabetes, while others expect their cat to be managed as a human family member.

The intent of this article is to compare tight and loose control of blood glucose for managing diabetes in cats so clinicians may tailor disease management to unique needs of owner and patient.

Tight versus loose glycemic control: Therapeutic goals and medical management

Tight protocol: The goal for treatment is to control blood glucose so that levels are as close to normal as possible to reduce glucose toxicity, which may, in turn, lessen insulin resistance and increase insulin production. Clients must test blood glucose at home and the insulin dose is frequently adjusted based on the blood glucose reading. Remission has been achieved when euglycemia is maintained without administration of exogenous insulin for a minimum of two weeks1. A variety of insulin types have been used to induce remission.

Loose control protocol: The goal for treatment is to control clinical signs (polyuria, polydipsia, weight loss). Blood glucose is “loosely” controlled: that is, insulin is dosed to reduce blood glucose below the renal threshold (250 to 300 mg/dL in cats) in order to manage clinical signs and prevent life-threatening complications such as diabetic ketoacidosis2. Physical examinations, weight, and history in combination with blood glucose levels are used to change insulin dose. Hyperglycemia can be acceptable if physical examination is normal and owner is satisfied with cat’s wellbeing. While remission is not the intent of loose control protocols, spontaneous remission can occur.

No matter which protocol is chosen, a change to a high-protein, low-carbohydrate diet is essential.

There are no data to suggest either protocol is better at improving long-term prognosis.

Patient selection criteria

Patient factors play a role in the success of remission protocols. Cats with poorly controlled concurrent disease or diabetes of longer than 180 days’ duration are unlikely to respond to an attempt to induce remission. Cats most likely to go into remission are newly diagnosed (less than 180 days), achieve glycemic control with low insulin doses, and tend to be older1.

Setting client expectations

No matter the treatment protocol, clients must be educated about the clinical signs of life-threatening hypoglycemia, as well as the signs of poor regulation. For clients whose cats achieve remission, it is essential to emphasize that their cat may return to the diabetic state and may then require lifelong insulin. They should be instructed to contact their veterinarian if any change in signs is seen.

For additional information about specific treatment and monitoring recommendations, refer to the 2018 AAHA Diabetes Management Guidelines for Dogs and Cats.


1. Gottlieb S, Rand J. Remission in cats: Including predictors and risk factors. Vet Clin Small Anim 43 (2013) 245-249.

2. Norsworthy G. Approaches to the diabetic cat. The feline patient: Unique approaches to a unique species. Indiana VMA Feb. 2, 2013.

Written by Bonnie Bragdon, DVM, MS

Senior Manager, Merck Animal Health Professional Services

Photo credit: © iStock/photokitchen

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