Survival and the development of azotemia after treatment of hyperthyroid cats.
BACKGROUND
Hyperthyroidism complicates the diagnosis of chronic kidney disease (CKD) as it increases glomerular filtration rate. No practical and reliable means for identifying those cats that will develop azotemia after treatment for hyperthyroidism has been identified. Hyperthyroidism is associated with proteinuria. Proteinuria has been correlated with decreased survival of cats with CKD and with progression of CKD.


OBJECTIVE
Proteinuria and other clinical parameters measured at diagnosis of hyperthyroidism will be associated with the development of azotemia and survival time.


METHODS
Three hundred client owned hyperthyroid cats treated in first opinion practice.


METHODS
Retrospective, cohort study relating clinical parameters in hyperthyroid cats at diagnosis to the development of azotemia within 240 days of diagnosis and survival time (all cause mortality). Multivariable logistic regression analysis was used to identify factors that were predictive of the development of azotemia. Multivariable Cox regression analysis was used to identify factors associated with survival.


RESULTS
Three hundred cats were eligible for survival analysis and 216 cats for analysis of factors associated with the development of azotemia. The median survival time was 417 days, and 15.3% (41/268) cats developed azotemia within 240 days of diagnosis of hyperthyroidism. Plasma concentrations of urea and creatinine were positively correlated with the development of azotemia. Plasma globulin concentration was negatively correlated with the development of azotemia. Age, urine protein:creatinine ratio, and the presence of hypertension were significantly correlated with decreased survival time. Urine specific gravity and PCV were significantly correlated with increased survival time.


CONCLUSIONS
The proteinuria associated with hyperthyroidism is not a mediator of progression of CKD; however, it does correlate with all cause mortality.
Williams
T L
TL
Department of Veterinary Clinical Sciences, Royal Veterinary College, North Mymms, Hatfield, UK. twilliams@rvc.ac.uk
Peak
K J
KJ
Brodbelt
D
D
Elliott
J
J
Syme
H M
HM
D000818:Animals; D053099:Azotemia / Q000209:etiology / Q000662:veterinary*; D002371:Cat Diseases / Q000188:drug therapy* / Q000209:etiology / Q000401:mortality; D002415:Cats; D005260:Female; D006980:Hyperthyroidism / Q000150:complications / Q000188:drug therapy / Q000401:mortality / Q000662:veterinary*; D008297:Male; D012189:Retrospective Studies