Comparison of methods to monitor dogs with hypercortisolism treated with trilostane.

Abstract

BACKGROUND: The use of adrenocorticotropic hormone stimulation test as method to monitor efficacy of trilostane treatment of hypercortisolism (HC) in dogs has been questioned. OBJECTIVES: To evaluate and compare 12 methods with which to monitor efficacy of trilostane treatment in dogs with HC. ANIMALS: Forty-five client-owned dogs with HC treated with trilostane q12h. METHODS: Prospective cross-sectional observational study. The dogs were categorized as well-controlled, undercontrolled, and unwell through a clinical score obtained from an owner questionnaire. The ability to correctly identify trilostane-treatment control of dogs with HC with the following variables was evaluated: before trilostane serum cortisol (prepill), before-ACTH serum cortisol, post-ACTH serum cortisol, plasma endogenous ACTH concentrations, prepill/eACTH ratio, serum haptoglobin (Hp) concentration, serum alanine aminotransferase (ALT), gamma-glutamyl transferase (&#x3b3;GT) and alkaline phosphatase activity, urine specific gravity, and urinary cortisol&#xa0;:&#xa0;creatinine ratio. RESULTS: Ninety-four re-evaluations of 44 dogs were included; 5 re-evaluations of 5 unwell dogs were excluded. Haptoglobin was significantly associated with the clinical score (P&#x2009;<&#x2009;.001) and in the receiver operating characteristic analysis, Hp cutoff of 151&#x2009;mg/dL correctly identified 90.0% of well-controlled dogs (specificity) and 65.6% of undercontrolled dogs (sensitivity). Alanine aminotransferase (P&#xa0;=&#xa0;.01) and &#x3b3;GT (P&#xa0;=&#xa0;.009) were significantly higher in undercontrolled dogs. Cutoff of ALT and &#x3b3;GT greater than or equal to 86&#x2009;U/L and 5.8&#xa0;U/L, respectively, were significantly associated with poor control of HC by trilostane. CONCLUSIONS AND CLINICAL IMPORTANCE: Of all the 12 variables, Hp, and to a lesser degree ALT and &#x3b3;GT, could be considered additional tools to the clinical picture to identify well-controlled and undercontrolled trilostane-treated dogs.