Diabetes

Diabetes Mellitus (Diabetes) causes the blood glucose level in a patient to become elevated due to a reduction in the production or efficacy of the indigenous hormone insulin. Diabetes in companion animals is on the increase in developed countries largely because of the rise in obesity. Diabetes in pets appears to follow the same trend observed in the human population. As lifestyles and diets of urban dwellers change from a more active to a sedentary one, obesity and diabetes increases. Both type I (insulin dependent) and type II (non-insulin dependent) diabetes is observed amongst pets, with dogs (particularly bitches) being susceptible to type I than cats.

In companion animals, as with humans, if the disease remains undiagnosed or untreated, it results in severe complications from poor circulation, cardiovascular disease, recurrent infections and organ failure[1] eventually leading to death.  Needless to say, the cost to pet owners of undiagnosed or untreated diabetes is much greater than if it is treated and managed.

When a diabetic animal is presented to the veterinary practice displaying clinical symptoms in line with diabetes,[2] the veterinarian generally follows the guidelines recommended by the American Animal Hospital Association (AAHA): Diabetes Management Guidelines for Cats and Dogs. In summary, the AAHA recommends a panel of tests but those essential to confirming a diagnosis are urine analysis, blood glucose (glucose curve) and a Fructosamine test.[3]

Once diagnosis is confirmed, on-going monitoring over a period of 3 to 6 months is recommended to assess the most effective treatment regimen to stabilize the pet’s blood glucose levels.[4] During this period the pet owner is encouraged to visit the veterinary practice 2-4 times to monitor the glycaemic status of the pet using either, one or both, the blood glucose and the serum Fructosamine test.

Once the pet is stabilized, the owner may be advised to visit the veterinary practice every 3 to 6 months to monitor the pet’s glycaemic status. This is achieved by measuring blood Fructosamine levels. However, a diabetic blood marker, designated HbA1c [5], can also be used to assess the glycaemic status. HbA1c has become the biomarker of choice for monitoring human diabetes and is approved by the American Diabetic Association. Glycated haemoglobin or HbA1c, as it is referred to, is a significantly more stable diabetic marker than Fructosamine and has a longer half-life. A Fructosamine reading informs the vet of the average blood glucose level in a pet over a period of 7 to 14 days preceding testing, whereas a reading of HbA1c provides the vet an average glucose level over 60 to 90 days. In this regard, HbA1c is a better long term biomarker for diabetes. Currently, however, an HbA1c test is neither available in a veterinary central laboratory or in a POC format for in-clinic use.  In addition, while the Fructosamine test is available for routine testing at veterinary laboratories, it is not available in a portable POC format.

Approximate Comparison of Blood Glucose,
HbA1c & Fructosamine Levels
Glucose (mg/dL) Fructosamine (µmol/L) HbA1c (%)
30 137.5 3.0
60 175 4.0
90 212.5 5.0
120 250 6.0
150 287.5 7.0
180 325 8.0
210 362.5 9.0
240 400 10.0
270 437.5 11.0
300 475 12.0
330 512.5 13.0
360 550 14.0
390 587.5 15.0

[1] Including cataracts, retinopathy, neuropathy and limb amputations.

[2] General symptoms noticed by the pet owner are likely to be a combination of the following; excess urination, excess thirst, excess hunger, weight loss, lethargy, glucose in urine.

[3] These are the minimum recommended tests. Other panel of tests determining thyroid and general well-being of the animal may also be recommended.

[4] A treatment plan could involve all of the following; change in diet, lifestyle (exercise) and administration of veterinary insulin

[5] Measuring HbA1c has greater clinical significance during this phase than Fructosamine because it enables the veterinarian to review the glycaemic control (average glucose) over 60-90 days prior to testing as opposed to 7-14 days. HbA1c is haemoglobin that has been modified by the excess glucose in the blood. Its concentration in relation normal haemoglobin (Hb) provides an indication of whether the dose of insulin (or oral drug) prescribed has worked to bring the blood sugar to an acceptable level.

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