The diagnosis of equine insulin dysregulation

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Background Endocrinopathic laminitis is common in horses and ponies, but the recurrence rate of the disease is poorly defined. Objectives To determine the incidence of, and risk factors for, the recurrence of endocrinopathic laminitis. Animals Privately owned horses and ponies with acute laminitis (n = 317, of which 276 cases with endocrinopathic laminitis were followed up to study completion). Methods This prospective cohort study collected data on veterinary‐diagnosed cases of acute laminitis for 2 years. Each case was classified on acceptance to the study as endocrinopathic or non‐endocrinopathic using data collected in a questionnaire completed by the animal's veterinarian. Follow‐up data were collected at regular intervals to determine whether the laminitis recurred in the 2‐year period after diagnosis. Results The recurrence rate for endocrinopathic laminitis was 34.1%. The risk of recurrence during the 2‐year study period increased with basal, fasted serum insulin concentration ( P ≤ .05), with the probability of recurrence increasing markedly as the insulin concentration increased beyond the normal range (0‐20 μIU/mL) to over the threshold for normal (up to approximately 45 μIU/mL). Being previously diagnosed with laminitis (before the study; P = .05) was also a risk factor for recurrent laminitis. Cases with a higher Obel grade of laminitis were likely ( P = .05) to recur sooner. Conclusions and clinical importance Knowing that hyperinsulinemia and being previously diagnosed with laminitis are significant risk factors for recurrence will enable clinicians to proactively address these factors, thereby potentially reducing the risk of recurrence of laminitis.

Section: Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Incidence and risk factors for recurrence of endocrinopathic laminitis in horses

Laat

Reiche

Sillence

et al. 2019

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“…Therefore, insulin dysregulation could still have been present in the animals with PPID and might have contributed to their laminitis. Other tests for insulin dysregulation, such as the OGT/OST or the combined glucose‐insulin test, would have been helpful to further investigate these cases . Further research on the relationship between PPID and EMS, and any effect on laminitis risk, is required.…”

Section: Discussionmentioning

confidence: 99%

Phenotypic, hormonal, and clinical characteristics of equine endocrinopathic laminitis

Laat

Sillence

Reiche

2019

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Background Equine endocrinopathic laminitis is common and can be associated with an underlying endocrinopathy, such as equine metabolic syndrome (EMS), pituitary pars intermedia dysfunction (PPID), pasture consumption, or any combination of these factors. Objectives The aim of the study was to improve the risk assessment capabilities of clinicians, and to inform management strategies, for acute endocrinopathic laminitis by prospectively examining the phenotypic, hormonal, and clinical characteristics of the disease in a large cohort. Animals Privately owned horses and ponies (n = 301) of any age, sex, or breed diagnosed with laminitis by a veterinarian. A history of laminitis was acceptable. Methods This was a prospective cohort study. Veterinarians provided information on each case via an online questionnaire after informed consent from the animal's owner, and all data were de‐identified before analysis. Serum insulin and plasma adrenocorticotrophic hormone concentrations were measured in each case. Results Most cases were recruited in spring (109/301; 36.2%). Concurrent EMS and PPID resulted in higher basal insulin concentrations (49 [21.5‐141]; P < .02) than if an animal had a single underlying cause for their laminitis. The insulin concentration was negatively correlated (r 2 = −0.38; P < .001) with the animal's height, being higher in ponies (33[10‐14]; P < .001) than horses (9.5 [3‐25.7]) and was positively correlated (r 2 = 0.12; P = .05) with their grade (severity) of laminitis. Conclusions and Clinical Importance Horses and ponies with concurrent endocrinopathies have more marked hyperinsulinemia. Higher basal insulin concentrations were associated with more severe lameness.

“…In our study, the insulin/glucose ratio was lower in nonsurvivors. This ratio is used to estimate pancreatic insulin secretion in response to a glycemic challenge . Although the use of proxies, such as this ratio, has not been fully validated in horses, this difference between survivors and nonsurvivors confirms that the degree of pancreatic dysfunction in nonsurvivors was worse than in survivors.…”

Section: Discussionmentioning

confidence: 99%

“…Equine serum insulin was measured using a radioimmunoassay previously validated in horses (intra‐ and inter‐assay variation: 5.2% and 6.4%, respectively) and blood glucose concentration was measured using a glucohexokinase colorimetric assay as previously described . A diagnosis of hyperinsulinemia was made if serum insulin concentration was >20 µIU/mL and a diagnosis of severe hyperinsulinemia was made if serum insulin concentration was >50 µIU/mL . A diagnosis of hyperglycemia was made if serum glucose concentration was > 124 mg/dL (upper limit of diagnostic laboratory reference range).…”

Section: Methodsmentioning

confidence: 99%

Insulin dysregulation in horses with systemic inflammatory response syndrome

Bertin

Ruffin-Taylor

Stewart

2018

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BackgroundSystemic inflammation is a cause of insulin dysregulation in many species, but the insulin and glucose dynamics in adult horses diagnosed with systemic inflammatory response syndrome (SIRS) are poorly documented.Hypothesis/ObjectivesIn SIRS in horses, insulin and glucose dynamics will be altered and associated with survival.AnimalsAdult horses diagnosed with SIRS admitted to a referral hospital.MethodsProspective study enrolling horses diagnosed with SIRS in which serum insulin and glucose concentrations were measured. Horses were grouped by outcome (survival, hyperinsulinemia, and hyperglycemia) and compared with P < .05 considered significant.ResultsFifty‐eight horses were included in the study and 36 (62%) survived. At admission, 21 horses (36%) were hyperinsulinemic and 44 horses (88%) were hyperglycemic, with survivors having significantly higher serum insulin and a significantly lower serum glucose concentration. Horses diagnosed with hyperinsulinemia at any time during hospitalization were 4 times more likely to survive whereas horses that were hyperglycemic at any time during hospitalization were 5 times less likely to survive. Serum glucose concentration and presence of hyperglycemia both were associated with severity of disease. Insulin/glucose ratio, reflecting insulin secretion, was significantly higher in survivors whereas glucose/insulin ratio, reflecting peripheral tissue insulin resistance, was significantly lower in nonsurvivors. Only in survivors was there a significant correlation between serum insulin and glucose concentrations.Conclusions and Clinical ImportanceHyperinsulinemia and hyperglycemia are common features of SIRS in horses, but those presenting with relative hypoinsulinemia and corresponding hyperglycemia suggestive of endocrine pancreatic dysfunction have a worse prognosis.