Evaluation of fasting plasma insulin and proxy measurements to assess insulin sensitivity in horses.
Authors: Lindåse Sanna, Nostell Katarina, Bergsten Peter, Forslund Anders, Bröjer Johan
Journal: BMC veterinary research
Summary
# Editorial Summary Insulin dysregulation is increasingly recognised in equine practice, yet the practical tools available for assessing insulin sensitivity remain inadequately validated in affected horses. Lindåse and colleagues evaluated how well five commonly used fasting-based proxy measurements—fasting insulin, 1/Insulin, RISQI, QUICKI, MIRG and HOMA-β—correlated with the gold-standard euglycemic hyperinsulinemic clamp in horses with and without insulin resistance, and assessed the day-to-day repeatability and optimal cut-off values for each marker. Single fasting plasma insulin emerged as the strongest predictor of insulin sensitivity status (determined by clamp testing), whilst the mathematical proxies offered no improvement in diagnostic accuracy despite their theoretical appeal; additionally, all measurements showed acceptable repeatability between consecutive days, suggesting that single-sample protocols are reliable in practice. For horses suspected of insulin dysregulation, practitioners should prioritise straightforward fasting insulin measurement over more complex proxy calculations, using evidence-based cut-off values rather than assuming proxy indices enhance clinical discrimination. These findings substantially simplify diagnostic protocols and redirect resources towards validated single-marker assessment, potentially improving the accessibility and consistency of insulin dysregulation screening across equine practice.
Read the full abstract on PubMed
Practical Takeaways
- •Fasting insulin and proxy calculations (particularly RISQI and QUICKI) can be reliably used to screen for insulin resistance in clinical practice, avoiding the need for expensive and time-consuming clamp testing
- •Use established cut-off values from this study when interpreting fasting insulin and proxy results to identify horses requiring dietary and management interventions for metabolic syndrome
- •Sampling on consecutive days shows good repeatability, so single-day fasting samples are adequate for clinical assessment; serial monitoring does not require multiple testing days
Key Findings
- •Fasting insulin and proxy measurements (1/Insulin, RISQI, QUICKI) showed variable correlation with the euglycemic hyperinsulinemic clamp (EHC) gold standard measure of insulin sensitivity in horses
- •RISQI and QUICKI demonstrated reasonable repeatability when measured on consecutive days, supporting their use in clinical practice
- •Optimal cut-off values for identifying insulin resistance in horses were established for fasting insulin, 1/Insulin, RISQI, and QUICKI proxies
- •Proxy measurements provide a practical alternative to EHC for assessing insulin sensitivity in equine patients with suspected insulin dysregulation