Initial investigation into the metabolic effects of intra-articular betamethasone on normal and insulin dysregulated horses

Given the metabolic effects of intra-articular (IA) corticosteroids, the goal of this project was to monitor the effects of IA betamethasone in both insulin dysregulated (ID)(n = 3) and non-ID (n = 5) horses. A cross-over design was used where eight geldings were injected with either 9 mg of betamethasone or saline into both metacarpophalangeal joints, followed by regular blood collections for adrenocorticotropin releasing hormone (ACTH), cortisol, insulin, and glucose, as well as pre- and post-administration oral sugar testing. Results were analyzed via two-way repeated measures analysis of variance (p < 0.05). Intra-articular betamethasone caused significant suppression of ACTH and cortisol in both groups through 24-48 hr, and a significant increase in glucose in the non-ID horses between 8-48 hr post-administration. As portions of this pilot study were underpowered (primarily insulin), additional work with larger numbers of both ID and non-ID horses would help to better understand these effects and allow for the analysis of insulin concentrations.