(E30) Prevalence of Insulin Dysregulation in Sport Horses as Determined by Traditional and Stall-Side Testing

Abstract: Background – Insulin dysregulation (ID) is a risk factor for laminitis, but the prevalence has not been investigated in sport horses. New stall-side assays offer convenience but need further validation. Objectives – To determine the prevalence of ID and in sport horses, identify parameters associated with disease, and evaluate a stall-side insulin assay. Animals – To date, 50 sport horses presenting for orthopedic evaluation with no prior history of confirmed insulin dysregulation (additional 150 to be tested). Methods – Cross-sectional observational study. Signalment and morphometric data including body condition and cresty neck scores were collected. Insulin, leptin, and total adiponectin were measured at baseline. Horses were administered 0.15 mL/kg light karo syrup and insulin measurements repeated after 60 and 90 minutes. Stall-side (Wellness Ready) insulin measurements were compared to a commercial laboratory (Tosoh Immunoassay). Simple logistic regression was used to identify predictors of ID. Agreement between insulin results was assessed with simple linear regression and a Bland-Altman plot. Results – No horses had increased basal insulin, but ID was confirmed in 12/50 (24%) with the oral sugar test. Univariate logistic regression identified no parameters associated with a diagnosis of ID. Simple linear regression showed significant correlation between tests (R2=0.64, P < 0.0001). Stall-side insulin concentrations averaged 14.3 uU/mL higher than the laboratory (95% LoA -2.9 to 31.5 uU/mL). Conclusions and Clinical Importance – ID is common in sport horses and dynamic insulin testing is necessary for diagnosis. Agreement between the stall-side assay and laboratory was fair and warrants further evaluation.