This is the second in a two-part story that originally ran in Catnip, the newsletter of Cummings School of Veterinary Medicine at Tufts; here is Part 1, which described the disease and focused on causes and diagnosis. My primary veterinary source at Tufts was Orla Mahony, ACVIM, ECVIM, a specialist in small animal endocrinology, and my primary catinary source was Mel Freer of No Dog About It. Strange but true.
Often, the most difficult — and costliest — phase of caring for a diabetic cat occurs right after diagnosis. Getting blood glucose levels stabilized is a complex process that involves finding the correct type and dose of insulin to administer. Cats metabolize insulin more quickly than dogs and than humans, so the longer-acting insulins known as PZI (prozinc) and Lantus are usually the most effective for them.
At minimum, you can expect your cat to spend several days in a veterinarian’s office or specialist’s clinic getting glucose curves — blood tests conducted over 12 or 24 hours that measure the amounts of glucose in the blood and chart the times at which those amounts peak and dip. To complement these tests and to spot check blood glucose levels, Dr. Mahony recommends home testing.
Home testing of blood glucose levels has become more and more popular among owners of diabetic cats. The top options, past, present, and future, are:
Urine test strips: When blood glucose levels get too high, the kidneys cannot filter effectively and glucose “overflows” into the urine. Test strips that are color coded to different glucose levels are readily available over the counter; some of these strips also measure ketones, the protein that appears in the urine when glucose levels remain dangerously high for a long time.
It’s not as difficult to get urine samples from a cat as one might think; methods range from placing plastic underneath your regular litter to using a more nonabsorbent variety temporarily.
But this method of testing is not very accurate. It takes a while for glucose to show up in urine, so the level recorded on the strip may reflect a reading several hours old, not one that is current. And while you can tell if there is extra glucose in the urine, you can’t tell if glucose levels are dangerously low.
This type of testing is also not practicable for people with more than one cat — which is common. Dr. Mahony says “People don’t like to confine their diabetic cat to one room of the house while they monitor the glucose.”
Still, it’s not a bad gauge initially for those who are a bit nervous about getting blood from their cat. And it’s clear that if glucose shows up in the urine every time you test, your cat likely needs an insulin dose increase. Dr. Mahony suggests this type of testing initially just to get a feel for what might be going on with the cat’s blood sugar.
Blood sample testing: The hand-held meters that measure glucose in a blood sample, now available in smaller veterinary versions, are a far better gauge of blood glucose levels than urine testing. And, according to Dr. Mahoney, it’s generally fairly easy to get blood from a cat’s ear. She says, “Any glucose meter that uses a microliter or less of blood is good, and there are more and more of these devices around.” She notes that the veterinary Alpha Track glucose meter was highly rated for pets in an independent study.
Dr. Mahoney recommends blood sample testing for cats that are difficult to regulate. “I will have clients try to do a glucose curve periodically, maybe once every week, at two-hour intervals for 12 hours.” For some clients, however, it’s more practical to spot test over the course of a week. “In either case,” Dr. Mahoney says, “it provides the comfort of having some knowledge about the cat’s condition,” adding, “It’s an especially good idea for owners who might be concerned that the glucose levels are too low.”
In addition, stress often raises blood glucose levels and cats are notoriously stressed at the vet’s office. Glucose curves done at home may therefore be a bit more accurate.
Continuous glucose monitoring. The newest devices on the market look like beepers and are attached to a censor that’s pushed in under the skin. They measure glucose in the subcutaneous tissues every five minutes. These systems are seen as a breakthrough for humans and have been tested on animals effectively, but at this point they’re bulky, especially for a small cat. It’s also easy for the censor to pop out in an active animal.
In addition, they’re still very expensive — typically, they cost over $1000 initially, not counting the price for the censors. They are being purchased by veterinary offices to be used instead of serial blood glucose curves, but are not yet practicable for the average pet owner.
Dr. Mahoney says, “It’s really just the start of glucose testing. In the future, there’ll be devices that will monitor glucose levels and administer insulin for humans automatically.” Whether they’d ever be feasible for animals remains to be seen. “Devices can be adjusted by people in case something goes wrong, if a passage gets blocked,” Dr. Mahony says. “Leaving an animal alone with one might not be safe.”
She also recommends that any female diabetic cat that has not been spayed have an ovariohysterectomy performed immediately. “Because of the complicated interactions between insulin and hormones produced by the ovaries, it’s very difficult to regulate an intact female cat,” Dr. Mahony says.
Treatment and maintenance
Most cats need to get insulin shots twice daily. As with humans, cats must eat before getting the shots in order to prevent hypoglycemia, dangerously low blood sugar. So once the correct dose of insulin is established, it’s important to keep glucose levels on an even keel by feeding the same amount of food at the same time each day.
It’s also ideal to get your cat slimmed down.
“If you were determined enough, you could probably do it,” Dr Mahoney says, “but it can be very difficult to get a diabetic cat to lose weight.” For one thing, she notes, “Clients are now being told they have to feed their cats twice a day because otherwise their glucose might dip. You’re trying to get your cat to eat while being concerned about her weight.”
It’s also difficult to get diabetic cats to exercise because they’re generally middle aged or older by the time the disease is diagnosed. “You can try to get them to move around more but it’s not that easy,” Dr. Mahony says.
Diets prove similarly challenging. “Low carbohydrate diets are a helpful development in feline diabetes,” Dr. Mahoney says. “But it’s difficult to find feline balanced diets that are both low carb and low fat. They either tend to be weight-control diets, which are lower fat and higher carbs, or low carb, which are not geared towards weight control.”
If she had to choose, Dr. Mahoney says, she would opt for the low carb. “Those diets do help.”
That said, it’s unusual for a cat to have a reversal of diabetes as a result of diet alone. “At Tufts, we may get 10% of cats off insulin,” Dr. Mahoney says. “Most of our cats require insulin and a proper diet for good control.” Some studies have a much higher rate of success with diet alone being responsible for getting cats into complete remission, she notes, and suggests that the remission rate may depend on the population of cats. But, Dr. Mahony says, “You’d have to recognize the disease very quickly for diet alone to be effective.”
The good news: Giving insulin shots is very manageable. Most cats don’t even notice the injections and, once the cat is regulated, giving them becomes very routine for owners.
“People seem to think giving shots is complicated but it’s not as hard as you think,” Freer says. “Sebastian never seemed to care. He never complained and never ran away from the shots.”
Nor was there any effect on his quality of life — or on Freer’s. Freer had her sister give Sebastian the shots when she had to go away, and he lived for another nine or ten years after he was diagnosed at age 7. “Sebastian was never sick until he was old,” Freer says. “And I never thought of him as a diabetic cat. He was a great cat who happened to have diabetes.”