Insulin resistance versus dysregulation—a distinction without a difference
Authors: Kellon E. M.
Journal: Equine Veterinary Education
Summary
# Insulin Resistance versus Dysregulation in Horses: Clarifying Terminology Over the past decade, equine practitioners have increasingly adopted the term "insulin dysregulation" to describe hyperinsulinaemic horses, partly to encompass a broader range of underlying causes than the more specific "insulin resistance." Kellon examined the evidence underpinning this terminological shift, reviewing the scientific literature for documented cases of hyperinsulinaemia occurring independently of true insulin resistance—defined rigorously as impaired cellular response to insulin as measured by euglycaemic hyperinsulinaemic clamp testing. The critical finding is that evidence supporting the existence of hyperinsulinaemia without concurrent insulin resistance in horses is weak to nonexistent, undermining the rationale for the diagnostic distinction that has become commonplace in equine practice. This distinction matters because imprecise terminology obscures our understanding of metabolic dysfunction and may lead to inappropriate management strategies that fail to address the underlying pathophysiology. Practitioners should reconsider their reliance on "insulin dysregulation" as a catch-all term and return to insulin resistance as the accurate descriptor for hyperinsulinaemic states in horses, reserving alternative terminology only when robust evidence demonstrates genuinely distinct mechanisms.
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Practical Takeaways
- •When discussing elevated insulin levels with colleagues, use 'insulin resistance' rather than 'insulin dysregulation'—the evidence supports this terminology and improves clinical communication
- •Understand that hyperinsulinaemia in horses reflects failure of insulin-sensitive tissues to respond normally to insulin, not a separate metabolic condition
- •Be aware that terminology matters in practice: using precise, evidence-based language helps standardise diagnosis and management of metabolic disease across the equine industry
Key Findings
- •The term 'insulin dysregulation' has replaced 'insulin resistance' in equine literature over the past 10 years without strong scientific justification
- •Evidence for hyperinsulinaemia occurring outside of insulin resistance in horses is weak to nonexistent
- •The euglycaemic hyperinsulinaemic clamp remains the gold standard for documenting insulin resistance in horses
- •The term 'insulin dysregulation' is considered a misnomer and should be abandoned in favour of 'insulin resistance'