An informal survey was taken on the Feline Diabetes Message
Board
on June 17, 2002 and again on July 26, 2002.
On the first date, the question was simply "How much insulin is your regulated cat getting?" and members quickly proposed adding weight and diet questions. The second survey was more specific, asking: for the amount, frequency (twice a day assumed), type of insulin, weight of cat, and composition of diet (low carbohydrate, dry, mixed were suggested as categories, but many people gave detailed responses). Regulation was not formally defined, but is largely understood by
members of the board to mean that the cat's blood glucose generally
ranges between 100 and 300 mg/dl over the course of a day, and
typically has a nadir in the
low 100's. It is likely that some respondents did not understand
that,
and two responses were eliminated when it became clear that the cat
rarely
dropped below 300 mg/dl. Click here for (redacted) raw
data.
The Results Number of observations: 69 observations on 64 cats (there were duplicates for a small number of cats who were regulated separately on high- and low-carb diets). Types of insulin: PZI (of various varieties, mostly animal-based) and Humulin Lente were the most popular types of insulin, with Humulin Ultralente coming in third. Together, these three types covered 72% of the respondents. (N.B. Lente and Ultralente are no longer being produced.) Insulin
Type Frequency Summary of doses: SID doses (5 cats) were divided by 2 for comparison purposes. Of the cats who were getting insulin (5 zero-dose cats not analyzed here), the mean dose was 3.0 units BID, and the median was 2.5 units BID. Values ranged from .125 units BID to 11 units BID. 16% of the cats needed 1 unit BID or less, and 36% were getting 2 units BID or less. Relationship between dose and weight: There was a positive relationship between dose and weight, although this disappeared after controlling for diet and insulin type. Further examination indicated that the cats receiving a combination of Lente and Ultralente tended to be the heaviest, and also tended to have the highest overall doses. Relationship between dose and insulin type: Generally, there was no relationship between dose and insulin type, with the exception of the Lente + Ultralente cats. The source of PZI (BR, BCP, UK, Humulin) was also not related to dose. Relationship between dose and diet: There was a very strong relationship between insulin dose and general dietary type (p<0.001, Kruskal-Wallis test).
9 out of those 28 (32%) were receiving 1 unit BID or less. The means of the high-carbohydrate, mixed, and unknown groups were not signficantly different from each other; however, the low sample size makes it difficult to detect differences. Controlling for insulin type and weight, and including the zero-dose cats, the cats on a low-carbohydrate diet had a significantly lower mean daily dose than the other three diets (p<.05, Tukey's test; p for high-carbohydrate diet vs low-carbohydrate diet = .0002). Even removing the zero-dose cats, the low-carbohydrate group had lower mean doses than the high-carbohydrate group (p=.0035). Standard deviation of error term = 1.75 units.Interpretation of results: Vets need to be very cautious with the initial dose of insulin, especially if the cat is on a low-carbohydrate diet. Even 2 units twice a day is too high for a starting dose, since almost half of our regulated cats on low-carb diets are below that dose. There may be some leeway for larger cats, but there's not enough information on variability to ensure that this is the case.
Note to readers: This document is copyright (C) 2002 by Janet M. Peerson. You may freely copy and distribute the document, and you are especially invited to link your web page to it, but you may not charge money for it (not even handling costs), and you may not claim credit for the contents. The original version was created August 4, 2002. If the information in this document was useful to you, please consider "paying forward" by making a donation to IMOM (www.imom.org), an all-volunteer non-profit organization which was founded to help people help their sick, injured, or abused animals. |
Results of Feline Diabetes "Initial Treatment"
Survey May 13, 2003 |
The Survey An informal survey was taken on the Feline Diabetes Message Board
(FDMB) on May 1, 2003 and May 3,2003 to assess the experience of the
members
with respect to very first treatment that their vet recommended when
their
cats were first diagnosed with diabetes. This survey is in no way
scientific
or representative of all diabetic cats. The specific questions
were: Data were entered into Excel and analyzed with SAS (R) for Windows
(Cary, NC). The Results Number of observations: 119 cats were represented for
121
observations (a couple of cats were diagnosed with diabetes twice). Initial treatment: The vast majority responding -- 86%
--
said their vets started their cats with insulin. This may be
because
vets prefer insulin, or it may be because insulin users are more likely
to
end up on the FDMB. This trend did not change over time (p=0.78,
chi-square
test).
Type of insulin: 33% of cats were started with N, 19% with L, 28% with U, and 13% with PZI. The remaining 7% received 70/30, Caninsulin, Iletin II, or Iletin NPH. There were no changes in the relative proportions of type of insulin over time (p=0.94, chi-square test on common insulins only). Frequency of insulin: 71% of cats were started on insulin twice a day, which also did not change over time (p=0.41, chi-square test). However, frequency was related to type of insulin; about 50% of Ultralente and PZI users were started with once a day dosing, whereas about 85% of L users and 90% of N users were started with twice a day dosing (p=.0006, chi-square test). Initial Dose: Total daily dose prescribed ranged from 0.5 to 34 units, with the median at 3.0 units daily, the first quartile at 2.0 units daily, and the third quartile at 4.0 units daily. After removing the vets who prescribed massive doses of 70/30 (10 units and 30 units respectively), there was no relationship between total daily dose and type of insulin (p=0.83, ANOVA). However, cats who were prescribed insulin twice a day tended to receive more (4.4 units vs 2.15 units, p=.005), or, in other words, the dose at each injection was the same regardless of whether one or two doses were prescribed. The total daily dose has not been changing over time (p=0.54, ANOVA). Diet: The type of food prescribed has been changing over time (p=.0006, chi-square). Before July 2000, 69% of cats were prescribed high-carb food and none low-carb food; between July 2000 and December 2001, 60% of cats were prescribed high-carb food and 13% low-carb food; during 2002, 31% of cats were prescribed high-carb food and 42% low-carb food; during 2003, 30% of cats were prescribed high-carb food and 39% low-carb food. Relationship between Diet and Dose: Somewhat disturbingly, the total prescribed dose was not lower for cats put on a low-carbohydrate diet (3.75 units daily for high-carb vs 2.83 units daily for low-carb, p=0.78), although research, anecdotal evidence, and our own insulin dose survey indicate that insulin requirements are less for cats on a low-carbohydrate diet. Prescribed diet was also not related to prescribed insulin type (p=0.39, renal diet and non-common insulins excluded). Comments: Except for diet, vet practices have not been changing much over the past few years. And although vets seem to be more open to recommending low-carbohydrate diets, it appears that they have not in general changed the type and dosage of insulin to match the physiological consequences of this diet. These conclusions might be seriously flawed by "selection bias," however, since cats who do not develop problems may be less likely to send their humans to the Internet in search of answers. Note to readers: This document is copyright (C) 2002 by Janet M. Peerson. You may freely copy and distribute the document, and you are especially invited to link your web page to it, but you may not charge money for it (not even handling costs), and you may not claim credit for the contents. The original version was created August 4, 2002. If the information in this document was useful to you, please consider "paying forward" by making a donation to IMOM (www.imom.org), an all-volunteer non-profit organization which was founded to help people help their sick, injured, or abused animals. |
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Last updated 02/10/07