Compliance also improves when client has stake in management
Home blood glucose monitoring is the care standard for human diabetics. In humans, glucose is typically monitored four to six times per day. Exogenous insulin by injection is contraindicated without home monitoring.
This is a safety issue, as glucose values in humans vary significantly day to day. This same daily variability has been documented in dogs and cats.
Variables known to influence glucose in both species include stress, excitement, exercise, quality and quantity of diet, as well as amount of insulin absorbed from the subcutaneous tissue. Varying the injection site leads to different absorption. For this reason, the author does not advise rotation of the injection site.
If local inflammation associated with repeat injections occurs, the injection site is changed to a new site rather than rotated between sites.
Variability in glucose also occurs in the absence of an explainable cause. Inconsistent glucose values are a source of frustration for veterinarians and owners. Once daily glucose monitoring is instituted, the magnitude of the fluctuations becomes apparent.
Simply stated, every day is not the same. In the absence of home monitoring, one is unlikely to be aware of the inconsistent values, as dogs and cats are quite tolerant to both hypoglycemia and hyperglycemia, with a paucity of recognizable clinical signs.
Knowing what the glucose is in real time is empowering, as it allows the pet owner to take an active role in the management of the pet’s diabetes and gives the veterinarian the data to make educated insulin dosing decisions.
Fructosamine levels are a valuable measure of the average blood glucose for the previous three weeks, but do not reflect daily fluctuations. Real-time values allow for real-time decision-making.
No veterinarian in the face of hypoglycemia would knowingly give his or her own diabetic pet insulin—or instruct a pet owner to do so. Unfortunately, this frequently happens because of a lack of home monitoring.
Likewise, if the glucose was high in the face of emerging disease, dietary indiscretion, stress, excitement or a somogyi phenomenon (insulin-induced hypoglycemia, followed by rebound hyperglycemia), a glucose curve or monitoring four times daily can be implemented to determine the correct therapeutic insulin dosage.
Veterinarians tend to err more toward hyperglycemia over hypoglycemia in glucose regulation, as the negative ramifications of the latter are clearly more life limiting in the short term. Long-term complications associated with hyperglycemia, although less immediate, can significantly impact quality of life.
Diabetic neuropathy, noted more frequently in cats than in dogs, results in hind limb weakness, difficulty walking, jumping and climbing stairs. Posterior capsular cataracts in the dog leading to blindness have an obvious negative impact on quality of life.
Patients whose glucose is monitored at home are generally on higher dosages of insulin safely with—for the most part—better glycemic control. Diabetic remission in the cat is much more likely with tight glycemic control, which can be achieved safely only with daily home monitoring.
Diabetic remission is promptly recognized with home testing.
“Guidelines for the Management of Diabetes,” published in the May/June 2010 AAHA Journal, advise home monitoring of glucose: “[It is] ideal and strongly encouraged to obtain the most accurate interpretation of glucose relative to clinical signs.”
Home monitoring eliminates the stress of transport and being in the hospital environment, and allows generation of a 12- to 14-hour blood glucose curve. At home, the curve is not truncated by the hospital or doctor’s schedule. The pet’s daily routine relative to exercise and feeding can be followed at home.
Duplicating the home environment in a caged pet is not possible. Caloric consumption is also hard to reproduce, as many patients do not eat well, or at all, in the hospital. The key difference here is who collects the data.
Empowering the pet owner to measure glucose at home ensures accurate, complete data, which is not attainable in the hospital setting. As a result, the veterinary clinician is able to accurately recommend adjustments in the insulin dose.
Considering staff time required to generate a glucose curve in the hospital, it is more profitable to have the pet owner generate the curve at home. Owners can be asked to perform a glucose curve that will be discussed, along with their daily blood glucose log, at the recheck visit. Owner compliance with long-term glucose monitoring is excellent and does not impact the frequency of re-evaluation by the veterinarian.
The majority of owners are able to learn how to collect capillary blood for home testing and most pets tolerate the procedure well.
A variety of testing sites lend themselves to pet and owner preference. Preferred testing sites in the cat and dog include the pisiform pad (nonweight bearing paw pad proximal to the carpal pad on the forelimbs) and lateral or marginal ear vein. The outer pinna is best in the cat and the inner pinna in the dog (best in dogs with floppy ears).
The buccal mucosa is optimal in large and medium sized dogs with good temperament. The lateral elbow callus in dogs can make sampling easy when it is present. Small dogs and those that exhibit a biting tendency when their ears, feet or mouth are handled do best with testing the redundant skin fold at the dorsal tail base, where a small area of hair can be clipped to facilitate testing.
Blood glucose is ideally measured first thing in the morning, prior to any food and insulin, and 12 hours later. The therapeutic goals are patient and owner driven, but in general the glucose should not be higher than 300 or lower than 80 mg/dl.
Home monitoring puts these seemingly lofty goals within reach, thereby improving the quality of life for both the pet and pet owner. Home monitoring also allows for use of more potent insulin, such as insulin detemir (Levemir), without risking life-threatening hypoglycemia.
Outlined in the October issue of Veterinary Practice News, the use of an insulin dosage chart avoids hypoglycemia, as insulin is not administered if the blood glucose is below a certain predetermined level (typically 120-150 mg/dl).
The insulin dosage chart directs the owner to administer insulin at or above a certain glucose level and withhold insulin if the glucose is too low or food intake is not adequate.
Dosage adjustments are made depending on the daily glucose values and the curve. Home monitoring of blood glucose values can be simply and safely mastered by most pet owners, resulting in a longer and healthier life for their pets and a more satisfied owner and veterinarian.
This Education Series article is underwritten by Abbott Animal Health of Abbott Park, Ill.