Diabetes occurs in dogs and cats and can be a frustrating illness. During a recent Fetch dvm360® virtual conference, Heather Kvitko-White, DVM, DACVIM, founder of KW Veterinary Consulting and The Pragmatic Professor, discussed key points veterinarians and pet owners should know about diabetes in order to manage disease as smoothly as possible shape.
to make a diagnosis
In dog patients, the presence of hyperglycemia and glucosuria is usually enough to diagnose diabetes. To avoid delayed diagnosis when sending samples to an outside laboratory for analysis, Kvitko-White recommends performing an internal blood glucose test on all patients with polyuria / polydipsia.
Diagnosing diabetes in cats is a little more difficult. Kvitko-White notes that transient stress hyperglycemia can cause blood sugar levels as high as 400 mg / dL, making hyperglycemia and glucosuria alone unreliable for diagnosis. Even the presence of ketonuria does not confirm the diagnosis. In cats, fructosamine levels are the most reliable way to confirm the diagnosis.
Choose an insulin
Insulin therapy is the cornerstone of diabetes management in veterinary patients. Therefore, choosing the best insulin for each patient is vital. Veterinarians should consider the duration of the insulin action (short-, medium-, or long-acting), the size and type of patient, the owner’s ability to deliver insulin and monitor the patient, and the likely cost to the owner. The initial dosage should be based on the lean body weight and type of insulin of the patient.
Kvitko-White discussed her personal preferences for insulin in patients of different sizes and types:
- Small to medium-sized dogs: Lente insulin (Vetsulin; Merck Animal Health) is a moderately effective insulin that is approved for use in dogs and cats. The vials should be changed every 42 days.
- Bigger dogs: Insulin Detemir (Levemir; Novo Nordisk) is a highly effective, long-acting insulin. This allows for smaller doses for large patients and contributes to cost savings over time.
- Cats: Insulin glargine (Lantus; sanofi-aventis). Kvitko-White noted that published recommendations often list Vetsulin or ProZinc (Boehringer-Ingelheim) as preferred types of insulin because they are FDA approved, not because they have superior control in cats.
The cost of insulin, especially long-acting insulins like detemir and glargine, can be alarming for some pet owners. Kvitko-White said that despite the higher up-front costs, owners of large dogs and cats will save money over time because vials of these insulins can be used for 6 months. In large dogs, shorter-acting insulins require higher doses and require frequent replacements, sometimes more than monthly. In cats, shorter-acting insulins are less effective and need to be replaced more frequently due to their durability.
An alternative insulin for small to medium-sized dogs whose owners are cost conscious is generic NPH insulin. This is not Kvitko-White’s first choice for a patient as the duration of action is shorter, usually only 4 to 10 hours. Because of this, diabetes control can be difficult and insulin sometimes needs to be dosed every 8 hours. However, these vials can be refrigerated for 30 to 60 days before they need to be replaced.
“When you diagnose a pet with diabetes, you need to prescribe three things: insulin, injections, and a prescription diet,” said Kvitko-White. Diabetic diets are low in carbohydrates, especially simple sugars. They use complex carbohydrates and fiber to help slow digestion. The goal of these diets is to minimize fluctuations in blood sugar, improve satiety, minimize the risk of pancreatitis, and promote weight loss.
Meal feeding is important for dogs on short to medium duration insulins. You should eat at least half of your meal before your insulin dose. For food-fed dogs, snacks are okay if they’re limited to less than 10% of total caloric intake and given in consistent amounts and at consistent times. Ideal snacks are apples, carrots, green beans, low-fat proteins, and sweet potatoes.
A change in diet is crucial for cat patients to achieve a state of remission. Your diet should be high in protein and low in carbohydrates. Meal-feeding is not required for cats on long-acting insulin such as glargine, and grazing with small, frequent meals throughout the day may be ideal due to the slow onset of glargine. Canned foods are preferred over dry food because they contain more moisture and protein, which promotes satiety and weight loss.
The role of glycemic graphs in monitoring
Kvitko-White knows that monitoring is “the frustrating part” of diabetes management. Just as there are numerous insulin options for veterinary patients, there are also many surveillance strategies. Their preference is to use glycemic graphs as the primary monitoring method, obtained conventionally, or to use continuous blood glucose monitoring systems, including the FreeStyle Libre System (Abbott). Curves allow you to identify when the nadir occurs, how low the blood sugar is at the nadir, how long the insulin works, and what the average glucose is during the day. The first curve should be done within 1 to 2 weeks of starting the insulin.
In an ideal curve, blood sugar should be measured before feeding and insulin administration and then every 2 to 3 hours during the day, depending on the type of insulin. Ideally, the patient is fed in the hospital and the veterinary team can watch the owner administering the insulin to make sure there are no mistakes. Because not all hospitalized patients eat, some patients must be fed and insulin-fed immediately before arriving at the hospital. How long we need to keep taking the measurements, “in reality,” said Kvitko-White, “we need to find the nadir and 2 points in the upswing” before we stop the curve.
Because the timing of the nadir is unpredictable, sample glucose tests are unreliable values to use when adjusting insulin doses. In a shorter-acting insulin like NPH, the nadir can occur as early as 1 to 3 hours after dosing. With longer-acting insulins such as detemir and glargine, a nadir may not occur at all or just before the next dose.
Home monitoring with AlphaTRAK (Zoetis) or Test Buddy (Trividia Health) may be a good option for some owners. This can reduce the effects of stress hyperglycemia and provide more data points when a 24 hour curve is needed. Kvitko-White does not recommend owners use an on-home monitoring system to adjust insulin doses themselves. Therefore, owners should be carefully selected for this type of surveillance.
Other monitoring strategies such as fructosamine levels and urine glucose monitoring can in some cases be used as additional diagnostics, but cannot replace the wealth of information that can be gleaned from a properly performed blood glucose graph.
Adjust insulin doses
Once the data has been collected via a blood sugar curve, the insulin dose can be adjusted. In underdosed patients, do not increase the dose by more than 10% to 20% at a time. All dose increases should be based on data. Kvitko-White reminded practitioners that pets that develop a Somogyi effect from an insulin overdose can be just as clinical as an uncontrolled, underdosed patient. Therefore, clinical symptoms alone should not be used to adjust the dosage.
In patients suspected or proven to be overdose, reduce the dose by 25% to 50% at a time. In extreme cases, some patients may need to be relieved of insulin for a short period of time. The veterinarian may want to consider changing insulin types when insulin therapy is resumed.
Customer communication pearls
Clear communication is critical to successful diabetes management. Preparing the owners for what to expect at the time of diagnosis is the best way to build a strong working relationship. It is important for all pets with diabetes to emphasize the importance of insulin therapy. No oral drugs currently control blood sugar in veterinary patients.
Dog owners need to know that diabetes – and therefore insulin therapy – is forever, with rare exceptions. In most cases, owners should be prepared for the initial inspection to take 4 to 6 weeks. But surveillance doesn’t stop there. “The insulin dose is not a shoe size,” said Kvitko-White, adding that requirements will change over time, requiring routine long-term monitoring. In addition, owners should be prepared for consequences such as diabetic cataracts.
Training for cat owners should focus on the goal of returning the pet to a non-insulin dependent state. Nutritional management and insulin therapy are both crucial components of treatment. Some cats, especially those whose diabetes is due to the use of iatrogenic steroids, can go into remission in as little as 2 weeks, which requires close monitoring.
Finally, Kvitko-White said it was important for owners to hear this: “When an owner cannot commit to it [insulin therapy] Financially or because they cannot commit to a time commitment to use insulin twice a day for the rest of their pet’s life, it is okay to euthanize them. “
“Diabetes is severe,” said Kvitko-White. Management can be frustrating, but it encourages practitioners to be patient. “I’m a big believer in data collection,” she said, “because we can’t predict how any particular insulin will work in an individual patient.”
If patients are not responding as expected, veterinarians should first verify customer compliance. How is insulin stored, handled and administered? How old is the bottle? What diet does the pet eat and how is the pet fed? When diabetes control remains elusive despite following customer guidelines, it encourages veterinarians not to be afraid of a change in insulin.
She also reminds practitioners that the 2018 AAHA Diabetes Management Policy for Dogs and Cats is a great resource. Finally, she says, “Don’t forget to contact specialists. Sometimes you just have to hear someone else’s experience. “
Kate Boatright, VMD, 2013 University of Pennsylvania graduate, is a practicing veterinarian and freelance speaker and writer based in western Pennsylvania. She is passionate about mentoring, education, and dealing with common sources of stress for veterinary teams and alumni. Outside of clinical practice, Boatright is actively involved in organized veterinary medicine at the local, state and national levels.