Factors affecting clinical assessment of insulin sensitivity in horses.
Authors: Firshman A M, Valberg S J
Journal: Equine veterinary journal
Summary
# Editorial Summary Insulin sensitivity assessment in horses remains clinically problematic because insulin resistance underlies several significant conditions—including pars intermedia dysfunction, equine metabolic syndrome, laminitis and osteochondrosis dissecans—yet no single practical and accurate diagnostic test currently exists. Firshman and Valberg's 2007 review synthesises evidence on measurement techniques, comparing tolerance testing and clamping methods whilst examining the multiple variables that confound results, including breed predisposition, reproductive status, body condition, nutritional composition and training regimens. The authors highlight that factors such as obesity, lactation, pregnancy and even supplement administration substantially alter insulin sensitivity measurements, meaning a single test result cannot be interpreted independently of an individual horse's metabolic and management context. Understanding these influencing variables is essential for practitioners seeking to diagnose insulin-related conditions accurately; blanket reference ranges risk both false positives and clinical misses. For farriers, veterinarians and nutritionists managing horses prone to metabolic disease, this work underscores the need for repeated testing under standardised conditions and consideration of the complete metabolic picture rather than reliance on isolated laboratory values.
Read the full abstract on PubMed
Practical Takeaways
- •Insulin resistance should be considered as a potential underlying factor in cases of laminitis, metabolic syndrome, and endotoxaemia; clinicians need better diagnostic tools to reliably assess insulin status
- •Body condition, nutritional management, and breeding/lactation status all significantly affect insulin sensitivity and should be evaluated when assessing metabolic health in individual horses
- •Current insulin testing has limitations; practitioners should be aware that tolerance testing and clamping techniques each have practical constraints and diagnostic accuracy considerations when selecting assessment methods
Key Findings
- •Insulin resistance is implicated in the pathogenesis of multiple equine conditions including laminitis, metabolic syndrome, and OCD, while increased insulin sensitivity characterizes PSSM and EMD
- •No single ideal test exists for evaluating insulin sensitivity in horses in terms of both practicality and accuracy, necessitating improved diagnostic techniques
- •Factors affecting insulin sensitivity in horses include breed, pregnancy, lactation, obesity, and nutritional factors, with additional influences from training, supplementation, and drug administration