Hyperinsulinaemia-Associated Laminitis: Why Some Horses Recover Slower Than Others

Over the last three decades, research has clearly established insulin dysregulation (ID) as the central mechanism underlying endocrinopathic laminitis¹. 

When susceptible horses or ponies consume pasture or feeds rich in non-structural carbohydrates (NSCs): 

• Blood glucose concentrations rise 

• Hyperinsulinaemia develops 

• Laminitis may be triggered directly 

• ² 

Because of this strong metabolic association, the condition is increasingly referred to as hyperinsulinaemia-associated laminitis (HAL)³. 

Which Horses Are Most at Risk? 

Certain groups appear particularly predisposed to HAL¹: 

Breed Predisposition 

“Easy keeper” breeds such as Welsh ponies are highly susceptible due to efficient glucose metabolism developed through evolutionary adaptation to seasonal feed shortages. 

PPID-Associated Risk 

Older horses with pituitary pars intermedia dysfunction (PPID) are also vulnerable because PPID is commonly associated with insulin dysregulation. 

Obesity and Fat Distribution 

While generalized obesity alone may not directly cause laminitis, regional fat accumulation—especially a cresty neck—is strongly linked with insulin dysregulation. 

Why Do Some Horses Recover Slowly? 

A clinical study evaluating naturally occurring HAL cases identified two distinct recovery patterns⁴: 

• Rapid improvement group: Horses showed marked improvement within approximately 14 days 

• Slow improvement group: Horses experienced prolonged recovery with waxing and waning clinical signs over several weeks 

This variability was observed despite appropriate veterinary management. 

Key Findings From the Study 

Glucose and Insulin Matter 

Persistently elevated blood glucose and insulin concentrations were most strongly associated with delayed recovery⁵. 

Although individual variation limits their usefulness as standalone prognostic markers, these findings reinforce the importance of metabolic control during rehabilitation. 

ACTH Was Not Directly Linked to Recovery Speed 

Interestingly: 

• ACTH concentrations did not predict recovery rate 

• PPID likely contributes indirectly through concurrent insulin dysregulation rather than ACTH itself 

Obesity Was Not a Major Predictor 

The study also found: 

• Generalized obesity was not significantly associated with slower recovery 

• Leptin concentrations showed no clear relationship with improvement rate 

Radiographs: Helpful but Limited 

Radiographic findings did not reliably predict recovery outcomes. 

Clinically important observations included¹: 

• Severe foot pain may occur despite minimal radiographic change 

• Radiographic abnormalities can persist long after clinical recovery 

• Previous laminitic episodes may complicate interpretation 

This highlights the importance of combining radiographic assessment with careful clinical evaluation. 

Practical Take-Home Messages for Veterinarians 

Focus on Metabolic Management 

Successful HAL management requires aggressive metabolic control alongside pain management and hoof support. 

Dietary NSC Restriction Is Critical 

Strict control of non-structural carbohydrate intake remains a cornerstone of therapy. 

Monitor Glucose and Insulin Trends 

Persistent elevations may indicate a risk for prolonged recovery. 

Emerging Therapies May Help 

Glucose-lowering agents such as velagliflozin may offer future therapeutic benefit in difficult cases. 

Prepare Owners for Variable Recovery 

Recovery timelines can differ substantially, even under optimal management conditions. Clear prognostic counselling is essential. 

Conclusion 

Hyperinsulinaemia-associated laminitis is fundamentally a metabolic disease rather than simply a hoof disorder. Early recognition, endocrine management, strict nutritional control, and realistic owner communication are critical to improving long-term outcomes in affected horses. 

References  

1. Sillence M, Meier A, de Laat M, Klee R, Reiche D. Demographic, morphologic, hormonal and metabolic factors associated with the rate of improvement from equine hyperinsulinaemia-associated laminitis. BMC veterinary research. 2022 Jan 18;18(1):49. https://doi.org/10.1186/s12917-022-03149-z  

2. de Laat M, McGowan C, Sillence M, Pollitt C. Equine laminitis: induced by 48 h hyperinsulinaemia in Standardbred horses. Equine Vet J. 2010;42(2):129–35. https://doi.org/10.2746/042516409x475779  

3. Frank N, Bailey S, Bertin F-R, de Laat M, Durham A, Kritchevsky J, et al. Recommendations for the diagnosis and treatment of equine metabolic syndrome (EMS). Equine Endocrinology Group: Tufts University; 2020. https://sites.tufts.edu/equineendogroup/files/2020/09/200592_EMS_Recommendations_Bro-FINAL.pdf   

4. Meier A, McGree J, Klee R, Preuß J, Reiche D, de Laat M, Sillence MN. The application of a new laminitis scoring method to model the rate and pattern of improvement from equine endocrinopathic laminitis. BMC Vet Res 2021; 17:16 https://doi.org/https://doi.org/10.1186/s12917-020-02715-7  

5. Meier A, Reiche D, de Laat M, Pollitt C, Walsh D, Sillence M. The sodiumglucose co-transporter 2 inhibitor velagliflozin reduces hyperinsulinemia and prevents laminitis in insulin-dysregulated ponies. PLoS One 2018;13(9): e0203655. https://doi.org/https://doi.org/10.1371/journal.pone.0203655