Clinical and laboratorial evaluation and treatment outcome in cats with hyperthyroidism

Abstract

Retrospective study analyzing a database of 50 hyperthyroid cats from two veterinary centers in Las Palmas de Gran Canaria, collected between October 2006 and May 2021. Clinical presentation, sensitivity of thyroid function tests, response to treatment and thus survival time of the population, were the focus of our objectives. Clinically, weight loss prevails over all other clinical findings, with a median body mass loss of more than 20%. Additionally, chronic kidney disease, cardiovascular disease, bowel disease and diabetes mellitus were found to be co-existing diseases in our hyperthyroid population. In order to confirm the diagnosis of hyperthyroidism, we performed thyroid function test, which sensitivity results for total T4, TSH and free T4 in this study were 94%, 100%, 100%, respectively. The follow-up study was conducted only with the animals that were treated with methimazole (n=25). A statistically significant difference (p=0.07) was found for total T4 concentration during the follow-up period, but not for dose (mg/kg) or blood creatinine level. Furthermore, the median survival time was 989 (IQR 795.82 - 1182.17) days and it was concluded that the survival time was significantly shorter for cats with CKD IRIS III/IV than for those with CKD level II.