Predictors of laminitis development in a cohort of nonlaminitic ponies.
Authors: Knowles Edward J, Elliott Jonathan, Harris Patricia A, Chang Yu-Mei, Menzies-Gow Nicola J
Journal: Equine veterinary journal
Summary
# Editorial Summary Over a four-year prospective study, Knowles and colleagues tracked 374 client-owned ponies to identify which metabolic markers and physical findings best predict laminitis development, addressing a significant gap in our ability to quantify individual risk. Among the 891 pony-years monitored, the team performed baseline and post-syrup insulin testing alongside measurements of ACTH, adiponectin, triglycerides and glucose, whilst recording physical examination findings and management factors; multivariable Cox regression models revealed that basal insulin ([insulin]T0) and 60-minute post-syrup insulin ([insulin]T60) emerged as the strongest predictors, with adiponectin and divergent hoof growth also independently associated with laminitis development—notably, basal ACTH did not retain statistical significance. The stratification by insulin concentration proved particularly valuable: ponies with basal insulin >45.2 µIU/ml faced a 69% four-year laminitis incidence compared to just 6% in those below 21.6 µIU/ml, whilst post-syrup insulin ≥153 µIU/ml carried a 73% incidence versus 3% below 53.4 µIU/ml. For practitioners, these findings provide evidence-based thresholds to identify high-risk ponies before clinical disease develops, though the results apply specifically to the insulin assays and management systems used in this UK-based cohort, and responses may differ in other breeds, regions or assay methodologies.
Read the full abstract on PubMed
Practical Takeaways
- •Request basal and 60-minute post-glucose insulin testing (corn syrup challenge) for nonlaminitic ponies to stratify laminitis risk; high fasting insulin (>45.2 µIU/ml) or stimulated insulin (≥153 µIU/ml) warrants aggressive dietary/management intervention.
- •Monitor hoof growth patterns as a clinical predictor—divergent growth is associated with increased laminitis risk independent of metabolic markers.
- •ACTH testing alone is not useful for laminitis risk prediction in nonlaminitic ponies; focus on insulin parameters instead.
Key Findings
- •Basal insulin [insulin]T0 and 60-minute post-glucose insulin [insulin]T60 were the strongest predictors of laminitis development, with high-risk ponies (>45.2 µIU/ml and ≥153 µIU/ml respectively) showing 69-73% 4-year laminitis incidence compared to 6-3% in low-risk groups.
- •Adiponectin and divergent hoof growth were independently associated with laminitis development, but ACTH was not.
- •Overall laminitis incidence was 4.8 cases per 100 pony-years across 374 ponies monitored for up to 4 years.
- •Risk stratification using insulin thresholds can identify 10% of the population at very high risk (69-73% incidence) versus 70-60% at low risk (3-6% incidence).