Originally published in the November 2014 issue of Veterinary Practice News
Fourteen diplomates from the American Board of Veterinary Practitioners (feline practice category) met at the American Association of Feline Practitioners meeting in Indianapolis to discuss the clinical management of diabetes in the cat.
Elaine Wexler-Mitchell, DVM, of The Cat Care Clinic in Orange, Calif., invited all ABVP feline diplomates to participate and to discuss the apparent disparity in the results of academic recommendations for managing diabetic cats and the clinical outcome that we, as in-the-trenches practitioners, have experienced.
The main expectation in question is that most, if not all, diabetic cats will go into remission if treated properly and that home glucose testing and the use of glargine insulin are essential parts of this.
Those answering Dr. Wexler-Mitchell’s call responded with the following statements:
- “I, too, do not see the same percentage of well-regulated diabetics as is reported. And I do not see the percent of remissions that they say we should in the first six months. I thought perhaps it was just me.”
- “A good number of my patients aren’t showing that degree of control or remission, nor are many of my clients as motivated as the ‘ideal.’”
- “My remission rates are also not that high. Did try a tight aggressive regulation right at diagnosis. Patient in remission and in hypoglycemic crisis in five days. So not as aggressive initially now. Blood glucoses are all over the place even with resolution of clinical signs.”
The diplomates observed that remission rates and overall management results were not as good as promised. The premise of the roundtable discussion was: “The approach to the feline diabetic that is recommended in veterinary schools and by academic speakers does not consistently produce the promised results when applied to a primary care practice setting.”
I prepared a spreadsheet that required 82 columns of data for each cat in the study. The spreadsheet was sent to each diplomate who committed to participating in the discussion. Ten feline practitioners submitted data on 290 cats that were diagnosed over the three-year period from July 1, 2011, through June 30, 2014.
Various factors were evaluated in relation to longevity and remission rates. These included diet, type of insulin used (especially protamine zinc vs. glargine), elevated fPLI at the time of diagnosis, occurrence of hypoglycemia, use of home glucose testing, occurrence of ketoacidosis, and occurrence of neuropathy.
The use of low carbohydrate (LC) high protein (HP) diets approached statistical significance, but the N was not sufficient to draw a firm conclusion. The other factors, including insulin type, did not have statistical significance, as determined by Annie Romeo, fourth-year veterinary student at Texas A&M University, who learned statistical analysis during a Ph.D. program in cancer research before entering veterinary school.
Romeo pointed out that even though the N of 290 was impressive, when the data were divided into the various factors mentioned, the power of most of the statistical tests performed was decreased due to the smaller sample sizes (N).
The remission rate for the entire 290 cats was 25 percent, considerably lower than what various experts have told us to expect. It was noted that the use of a certain type of insulin or a certain treatment protocol should ensure 100 percent success.
However, the discussion led to the conclusion that many factors influence remission, including the type of insulin used; a cat’s habitat (indoors vs. outdoors); owner motivation toward this particular cat; owner compliance, which is often influenced by finances, scheduling and other life commitments; diet; concurrent disease; and the success of correcting causes of insulin resistance, such as obesity.
We concluded that if board-certified feline practitioners get only about 25 percent of their feline diabetics into remission, the expectation of a significantly higher remission rate is not realistic and practitioners should not feel guilty about not achieving high remission rates in their patients.
We agreed fully that remission is a worthy goal, but the most realistic goal for managing a diabetic cat is restoring quality of life so the cat can interact normally with its owner, and part of this is developing a treatment protocol that is workable for clients who have other obligations in their lives.
Four cats in the data set lived more than 900 days. Data from these cats were examined for common factors. All were male, over 10 years of age, and receiving glargine. In addition, all died of diseases other than the direct effects of diabetes. However, that is where consistency stopped.
Twenty-five percent had blood glucose checked at home; 75 percent ate a low carbohydrate diet; and 25 had a recent history of steroid administration prior to the onset of diabetes. The panel concluded that successful treatment of diabetes is multifactorial, as is induction of remission.
Data from cats that were alive at the end of the three-year study were also examined with emphasis on the four practices with the highest number of cats in the study.
Fifty-four to 72 percent of cats from these practices were still alive. The panel considered this to be a sign of good control. Even though some of these were diagnosed near the end of the study, most were alive for well over one year and some up to three years. It was also noted that 32 percent of these cats went into remission, while only 15 percent of the cats that died did.
We discussed home glucose testing. Over 80 percent of the panel members recommend it although a survey of the members revealed that only about 21 percent of clients are willing to do so. It was pointed out that in a multicat household the best monitor for clinical signs is having the owner weigh the cat about once per week using a digital scale.
We discussed that the best benefit of home glucose monitoring may be in decreasing patient stress, since the patient is not coming to the clinic, but that the values reported by owners do not seem significantly different than those obtained during clinic visits for the same patients, which agreed with a study comparing home testing and clinic testing.1
The panel reviewed a study regarding the duration of action (DOA) of glargine.2 It was noted that there is a great deal of variation in the DOA of glargine with 50 percent having a DOA less than 12 hours and as few as eight hours in 40 percent of cats. Since it was the most common insulin used by the panel members, we agreed that many cats do well on it, but the frustration that many experienced appeared to be explained by this study.
The tight control approach3 was discussed. Many panel members had tried it, but no one was still using it. The most common problem encountered was excessive hypoglycemic events.
Bill Folger, DVM, noted that a hypoglycemic crisis treated at a local emergency clinic would cost the owner about $1,500 in the Houston area, and two events usually result in euthanasia.
It was also noted that the protocol required blood-glucose-testing an average of five times every day, which panel members would not recommend to their clients.
Low-carbohydrate diets were further discussed even though there was not statistical evidence for using them. Every panel member recommended LC diets and strongly believe that diabetic control is improved with it. It was also noted that we are in the midst of a shift to LC, HP diets for most if not all cats, including those with renal disease.
I noted that I have been feeding cats with chronic renal disease a LC, HP diet for over two years and am not seeing the decline in renal function we have all been taught to expect. In fact, these cats have a better overall quality of life and quit having muscle loss that is so typical in older cats.
Another interesting discussion regarded reliability of the dietary data. We all know that clients sometimes tell us what we want to hear and that “Yes, he is eating a LC, HP diet.” really means “Yes, he gets some of that special food, but he also gets some treats and a little of the other cats’ food.”
Thus, some cats given credit for being on a LC, HP diet may really not be on one. Those cats then are counted in the non-remission group degrading the results of that group.
We also discussed possible differences in university/referral outcomes vs. primary care practice outcomes. I pointed out that I see three time divisions for newly diagnosed cats, the first consisting of those that live zero to seven days. They are usually euthanized because they are so ill that the prognosis is poor due to ketoacidosis and/or other diseases like renal failure and neoplasia.
Others in this group are euthanized because owners are not financially capable of caring for a diabetic cat or have no desire to do so. These cats do not get to university/referral centers. They degrade our longevity and remission rates while not affecting those of university/referral practices.
Each panel member expressed interest in reconvening for another panel discussion next year. They were resolute in desiring to obtain more data by enlisting more ABVP diplomates to increase the statistical power. They also expressed gratitude for sponsorship from Boehringer-Ingelheim Vetmedica, Inc.
1. Alt N, Kley S, Haessig M, Reusch CE. Day-to-day variability of glucose concentration curves generated at home in cats with diabetes mellitus. JAVMA 2007;230:1011-1017.
2. Gilor C, Ridge TK, Attermeier KJ, Graves TK. Pharmacodynamics of Insulin Detemir and Insulin Glargine Assessed by an Isoglycemic Clamp Method in Healthy Cats. J Vet Intern Med. 2010;24:870-874.
3. Roomp K, Rand J. Intensive blood glucose control is safe and effective in diabetic cats using home monitoring and treatment with glargine. J Fel Med Surg. 2009;11:668-682.
- Bill Folger, Memorial Cat Hospital, Houston
- Alice Johns, The Cat Doctor, Indianapolis
- Kathleen Keefe Ternes, The Feline Hospital, Salem, Mass.
- Carrie Ann Mark, Kitten to Cat Hospital, Southlake, Texas
- Mary McCaine, Memorial Cat Hospital, Houston
- Margaret McIsaac, Granby Animal Clinic, Granby, Mass.
- Gary Norsworthy, Alamo Feline Health Center, San Antonio
- Anne Sinclair, Cat Sense Feline Hospital, Bel Air, Md.
- Sandra Wedig, Prairie Veterinary Associates, Sun Prairie, Wis.
- Elaine Wexler-Mitchell, The Cat Care Clinic, Orange, Calif.
- Cathy Eastman, Scottsbluff, Neb.
- Lorraine Jarboe, Veterinary Relief Services, Fort Walton Beach, Fla.
- Kelly St. Denis, Charing Cross Cat Clinic, Brantford, Ontario, Canada
- Vicki Thayer, Winn Feline Foundation, Lebanon, Ore.