Research Updates: Giving glargine insulin to newly diagnosed diabetic cats may increase the likelihood of remission


Research Updates: Giving glargine insulin to newly diagnosed diabetic cats may increase the likelihood of remission

Sep 01, 2010

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Diabetic remission, defined as reversion from a hyperglycemic to normoglycemic state in a diabetic patient after discontinuing insulin therapy, has been reported in cats that first present with uncomplicated diabetes mellitus or for treatment of diabetic ketoacidosis. Authors of previous studies have suggested that the success of glycemic control or the type of insulin being administered may affect the remission rate. This study's goal was to determine and compare the likelihood of remission in cats with newly diagnosed diabetes mellitus when treated with glargine insulin, protamine zinc insulin (PZI), or Lente insulin given subcutaneously twice a day.

Erika Meler, DVM, MS
In this nonrandomized, prospective study, 24 cats in which diabetes mellitus had been diagnosed within the preceding 24 hours were enrolled. Initial assessment included performing a physical examination, serum chemistry profile, urinalysis, and urine bacterial culture. Each cat's fructosamine concentration was also determined. All cats with serious concurrent diseases were excluded from the study.

Barrak Pressler, DVM, PhD, DACVIM
Enrolled patients included 21 cats with adequate food consumption and a lack of systemic signs that allowed immediate administration of one of the three subcutaneous insulins and three cats that required treatment with intravenous fluids and regular insulin before subcutaneous insulin administration could be started. Cats were distributed into the three insulin treatment groups with an attempt made to evenly match groups based on breed (Burmese vs. non-Burmese) and whether or not the cats had previously been given corticosteroids.

The initial dose of subcutaneous insulin was between 0.25 and 0.5 IU/kg, as determined by the serum glucose concentration (< 360 mg/dl [< 20 mmol/L] vs. > 360 mg/dl, respectively). All cats were fed an identical ultra-low-carbohydrate-and-high-protein canned food (failure to eat this food was grounds for exclusion), and blood glucose curves were performed at regular intervals with the insulin dose adjusted by following a standard study-specific dosing chart. Diabetic remission was defined as having serum blood glucose concentrations within the reference range two weeks after discontinuing insulin administration.

In this study, by day 17, the cats receiving glargine insulin had a significantly lower mean daily blood glucose concentration than cats receiving either PZI or Lente insulin did. Consistent with this finding, cats receiving glargine insulin had significantly lower serum fructosamine concentrations at day 56 than did either of the other two treatment groups. The number of cats achieving diabetic remission was 100% (n=8) in the glargine insulin group vs. 38% (n=3) in the PZI group and 25% (n=2) in the Lente insulin group. Of the cats that had not achieved diabetic remission by day 17, those with lower mean 12-hour blood glucose concentrations (< 288 mg/dl [16 mmol/L]) were more likely to eventually achieve remission. Although some cats in the glargine insulin group developed hypoglycemia when treated according to the study's insulin dosing chart, none had clinical signs referable to this abnormality.

The likelihood of achieving diabetic remission was not associated with breed (Burmese vs. other breeds). Both of the cats that had previously received glucocorticoids achieved remission.