Association between hyperinsulinaemia and laminitis severity at the time of pituitary pars intermedia dysfunction diagnosis.
Authors: Tadros E M, Fowlie J G, Refsal K R, Marteniuk J, Schott H C
Journal: Equine veterinary journal
Summary
# Editorial Summary Hyperinsulinaemia is emerging as the primary driver of laminitis in horses and ponies with pituitary pars intermedia dysfunction (PPID), yet the relationship between insulin elevation and laminitis severity remains poorly characterised in clinical populations. Tadros and colleagues examined 38 PPID-affected animals, measuring fasting serum insulin concentrations alongside radiographic assessment of distal phalangeal rotation and owner-reported laminitis history, then stratified animals into normoinsulinaemic (<20 µU/ml), mildly hyperinsulinaemic (20–50 µU/ml) and severely hyperinsulinaemic (>50 µU/ml) groups. Three-quarters of the cohort showed radiographic evidence of laminitis despite only 37% being recognised as laminitic by their owners; notably, owners detected laminitis more readily as hyperinsulinaemia worsened, and animals with moderate-to-severe radiographic changes exhibited significantly higher mean insulin concentrations (74.1 µU/ml) compared to those with normal-to-mild changes (31.9 µU/ml). These findings underscore that subclinical laminitis is widespread at PPID diagnosis and easily overlooked, particularly in normoinsulinaemic cases, whilst the correlation between insulin magnitude and radiographic severity strengthens the case for aggressive insulin management as a cornerstone of PPID-related laminitis prevention. Clinicians should initiate rigorous baseline radiographic screening and sustained insulin control in all newly diagnosed PPID cases, recognising that owner perception alone will miss the majority of endocrinopathic laminitis.
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Practical Takeaways
- •Radiographically screen all PPID-diagnosed horses for laminitis regardless of owner-reported lameness history, as subclinical radiographic changes are present in 76% of cases
- •Insulin concentration severity correlates with laminitis severity; severely hyperinsulinaemic horses (>50 µU/ml) warrant more aggressive metabolic management and closer laminitis monitoring
- •Client education is critical—owners frequently miss chronic laminitis signs, so veterinarians should proactively discuss radiographic findings and explain the hyperinsulinaemia-laminitis link
Key Findings
- •76% of PPID-affected equids had radiographic evidence of laminitis, but only 37% were reported as laminitic by owners (P = 0.01)
- •Owner recognition of laminitis increased with severity of hyperinsulinaemia (P = 0.03)
- •Mean serum insulin concentrations were significantly higher in equids with moderate to severe radiographic laminitis (74.1 µU/ml) compared to normal to mild laminitis (31.9 µU/ml; P = 0.03)
- •Chronic endocrinopathic laminitis remains frequently unrecognised by horse owners despite radiographic abnormalities at time of PPID diagnosis