Factors Predictive of Non-Insulin Dependence in Diabetic Cats Initially Treated with Insulin
Diabetic cats treated with insulin are frequently able to maintain euglycemia without insulin therapy within weeks to months of beginning treatment, often termed diabetic remission. The aim of this study was to determine the factors which might predict non-insulin dependence in insulin-treated diabetic cats.
Fifty-five cats diagnosed with diabetes whose owners followed an intensive blood glucose regulation protocol using glargine and fed a low carbohydrate diet were studied. Cats diagnosed with acromegaly were excluded. Fifty cats in the cohort were initially treated with other insulins (47 with porcine lente insulin) for a median of 15 weeks, but failed to achieve remission prior to switching to glargine and an intensive blood glucose regulation protocol.
Thirty-five cats (64%) in the cohort achieved remission. Cats treated with corticosteroid in the 6 months prior to being diagnosed with diabetes were more likely to go into remission than cats without prior corticosteroid treatment (P = 0.0014, Fisher's exact test, 95% CI 2.45, Inf). Cats which displayed a plantigrade stance at diagnosis or milder signs of peripheral neuropathy such as a difficulty climbing stairs, were significantly less likely to go into remission (P = 0.0036, Fisher's exact test, 95% CI 0.018, 0.606). However, when cats with only a plantigrade stance were examined, that is, cats with milder forms of peripheral neuropathy were excluded, the results were no longer significant. There was a significant difference in mean maximum insulin dose between cats which became non-insulin dependent during the study (0.43 IU/kg BID) and cats which remained insulin dependent (0.66 IU/kg BID) (P = 0.016, Wilcoxon rank sum test with continuity correction). Cats that started with intensive blood glucose control within 180 days (6 months) of diagnosis of diabetes were more likely to achieve non-insulin dependence than cats that were put on the protocol later than 180 days after diagnosis (P < 0.001, Fisher's exact test, 95% CI 2.42, 45.48).
Other factors which were examined but were not predictors of remission were age at diagnosis, gender, weight at diagnosis, evidence of diabetic ketoacidosis at diagnosis, development of azotemia during therapy, hyperthyroidism and frequency of asymptotic hypoglycemia. Obesity was not negatively correlated with remission.
We conclude that prior corticosteroid treatment, peripheral neuropathy, lower maximum insulin dose and intensively managed blood glucose concentrations using glargine within 6 months of diagnosis are associated with higher rates of non-insulin dependence in diabetic cats.