Automated insulin delivery system use leads to diabetic remission in a cat

A recent article in the Journal of Veterinary Internal Medicine highlighted a unique case of diabetes management in a cat that was the result of a pet parent acting without veterinary supervision and applying an automated insulin delivery (AID) system to their diabetic cat.  

The AID consists of three components: the wearable continuous glucose monitor (CGM) that takes frequent measurements of the patient’s interstitial glucose levels, a wearable insulin pump loaded with regular insulin that injects the insulin subcutaneously, and an app on a smart device the communicates wirelessly with both wearables to coordinate the administration of insulin based on glucose readings using a predetermined algorithm.  

Filippo Fierri, DVM, PhD, Dipl. ECVIM-CA, internist at the AniCura Istituto Veterinario Novara in Novara, Italy, was one of the authors of the article. He said that there are no official data on the number of human diabetic patients using AID systems, and that the count likely varies significantly between countries around the world. Whatever the number is, he said, “only a minority of diabetic people are using these devices.” 

Instances of AID system use in non-human species are even more rare.  

The case details 

The case report describes an 11-year-old male neutered domestic shorthair cat who had been newly diagnosed with diabetes mellitus. He had been started on long-acting insulin (protamine zinc insulin) by his veterinarian, and a CGM had been placed to monitor his glucose levels. After 5 days of insulin treatment and CGM readings that indicated poor diabetes regulation, the pet parent decided, without consulting with their veterinarian, to purchase a wearable insulin pump designed for human diabetic patients. 

The pet parent then programed an app on their smartphone to connect to both the CGM and the pump, creating an AID system. They set the ideal glucose concentration range and indicated how much insulin to give if glucose rates were to exceed this range.  

They then aseptically filled the pump with regular insulin diluted with sterile diluent, clipped and aseptically prepped the cat’s skin, and then attached the pump using a medical adhesive.  

The pet parent continued monitoring their cat’s glucose readings and ensuring all the elements of the AID system were functioning as intended, replacing the insulin pump every 3 days.  

After the first few days, the cat’s glucose concentrations mostly remained in the normal range with lower amounts of insulin needed to achieve glycemic control. By day 33, he maintained normoglycemia without any insulin, and he has remained in diabetic remission for over two years.  

Diabetic remission and other benefits of AID systems 

According to the study authors, when functioning properly, the AID system acts “similarly to a physiological pancreas, dynamically injecting or withholding insulin delivery based on real-time glucose measurements.” This is because the short-acting insulin doses can be modified frequently and given as often as needed without relying on human intervention to test and analyze glucose levels and administer the insulin.  

“Regular insulin allows for a rapid and effective management of glucose concentrations and their variations, something that cannot be achieved with intermediated-, long-acting and ultra-long-acting insulins,” Ferri said. “The main goal of the insulin pump is to achieve euglycemia (i.e., normal glucose concentrations) and the automated insulin delivery systems (closed loops or artificial pancreas) have been created with this goal in mind.” 

This level of glycemic control can significantly reduce the risk of glucotoxicity (defined as damage to the remaining insulin-secreting β-cells in the pancreas caused by high blood sugar levels).   

Preserving viable β-cells that can secret endogenous insulin may increase the likelihood that a cat will enter into diabetic remission, the authors suggested, adding that this hypothesis needs to be confirmed with future prospective studies.  

 “We firmly believe that the tight glycemic control has drastically decreased the glucotoxicity in the cat,” Ferri said, which likely played “a significant role in achieving remission.”  

Other benefits to using an AID system in cats include not having to inject a patient with insulin or administer oral medication daily and not having to use anesthesia or sedation to implant an insulin pump.   

AID systems could also be good options for cats who are not good candidates for treatment with an SGLT2 inhibitor drug or who developed euglycemic diabetic ketoacidosis while taking an SGLT2 inhibitor drug. 

Why isn’t AID system use in cats widespread? 

Replacement frequency and cost 

Ferri noted that there are some significant barriers to widespread use of AID systems in cats as they exist now. First, wearable insulin pumps typically need to be replaced every three days. This will require frequent aseptic filling of the pump with insulin, appropriate dilution of insulin, and handling the cat for aseptic skin preparation and attachment of the device. This would be a tall order for many pet parents. 

Ferri also said that the insulin pumps on the market now are “relatively expensive.” And with a duration of only three days, the cost of utilizing one long term if a cat doesn’t go into remission could be significant.  

Monitoring, proximity, and potential malfunction 

Despite what the name implies, AID systems do require some human input and monitoring to ensure they function properly. They must be appropriately paired with the app being used, and appropriate parameters must be set to maximize the likelihood that the patient will achieve euglycemia.  

A unique challenge with animals (as opposed to humans) is that they don’t necessarily stay close to the smart device used to run the app, which can result in missed readings and missed prompts to administer insulin. 

There is also some risk of pump malfunction, as noted in this case report. There were times where the pet parent had to remove the malfunctioning pump and administer long-acting insulin.  

There is also a risk that one or both of the wearables could fall off or be removed by the cat.  

What does the future of AID use in cats look like? 

Ferri believes that even with the obstacles previously described, AID systems will eventually have a place in the treatment of diabetes mellitus in cats. “I am confident that in the future we will have more owner-friendly devices available,” he said. 

“In addition, we think that the potential benefit on the rate of diabetic remission, after a short-term use of the current technologies in diabetic cats,” Ferri said, “would impact how widely they might be used.” 

Photo credit: Jon Hayt/iStock via Getty Images Plus 

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