2015 ACVIM Forum Research Abstract Program

Of the 515 enrolled horses, 61.7% were diagnosed with an endocrine disorder (PPID and/or hyperinsulinemia). As expected, PPID prevalence increased significantly (P < 0.001) by age and was significantly higher in horses with above-normal levels of both insulin and glucose (P = 0.014 and P = 0.016, respectively). Further, forty-three percent of PPID horses were also hyperinsulinemic. Therefore, when evaluating horses with suspected endocrine disease, at a minimum, ACTH, insulin and glucose should be evaluated. Long term studies need to be conducted in large populations of horses to further evaluate endocrinopathies in horses. It is often necessary to test for pituitary pars intermedia dysfunction (PPID) and insulin dysregulation in the same horse. We hypothesized that results of the thyrotropin-releasing hormone (TRH) stimulation test would not be affected by feeding conditions or the oral sugar test (OST).