Abstract: Background: Glucocorticoids are frequently administered to horses, and this treatment is associated with risk of hyperinsulinemia-associated laminitis (HAL). Methods to predict development of treatment-associated HAL are needed.
Hypothesis/objectives: Evaluate insulin and glucose dynamics before and after administration of dexamethasone (0.08 mg/kg PO q24 hours; DEX) and compare results between horses that subsequently developed laminitis (LAM) and those that did not (NONLAM) after a 14-day course of DEX administration. We hypothesized that insulin and glucose dynamics would differ between LAM and NONLAM horses.
Animals: 33 healthy adult horses were included.
Methods: Frequently-sampled insulin-modified IV glucose tolerance tests (FSIGTT) and oral sugar tests (OST) were performed at baseline and after 7 days of treatment with DEX. Minimal Model analysis was performed using FSIGTT data, and areas under the curve (AUC) of [insulin] (AUCins) and [glucose] (AUCg) were calculated from OST data. Paired Student’s t-tests were used to compare LAM and NONLAM groups at baseline and after DEX.
Results: 5/33 horses (15.15%) developed clinical signs of laminitis during or shortly after the 14-day study period. AIRg (acute insulin response to glucose; p = 0.01) and AUCins (p = 0.002) were significantly higher in LAM versus NONLAM horses at baseline. Additionally, AUCins (p = 0.02) was significantly higher in LAM after DEX.
Conclusions and clinical importance: AIRg and AUCins calculated from the FSIGTT and OST, respectively, could predict development of HAL associated with glucocorticoid treatment and should be evaluated as biomarkers of this risk.
.jpg "Erin F. Pinnell, DVM photo")
