Association between hyperinsulinaemia and laminitis severity at the time of pituitary pars intermedia dysfunction diagnosis.
Abstract: Hyperinsulinaemia is the suspected component of insulin dysregulation having the strongest association with laminitis and occurs variably in equids with pituitary pars intermedia dysfunction (PPID). Objective: We hypothesised that magnitude of hyperinsulinaemia correlates with laminitis severity in PPID-affected equids. Furthermore, we hypothesised that owners can be unaware of chronic endocrinopathic laminitis. Methods: Cross-sectional study. Methods: Serum insulin concentrations, owner-reported laminitis history and radiographic evidence of laminitis were determined in 38 client-owned horses and ponies with confirmed PPID. Laminitis severity was classified into four categories (normal [nonlaminitic], mild, moderate or severe laminitis) based on degree of distal phalangeal rotation. Animals were also categorised as normoinsulinaemic (50 μU/ml). One-way ANOVA, t tests and Fisher's exact tests were performed. Results: While owners reported laminitis in 37% of animals, 76% were laminitic based on study criteria (P = 0.01). Owners reported laminitis more frequently in hyperinsulinaemic vs. normoinsulinaemic animals; recognition increased with severity of hyperinsulinaemia (P = 0.03). Mean insulin concentrations were higher in equids with moderate to severe radiographic laminitis (geometric mean 74.1, 95% confidence interval (CI) 38.4-143.1 uU/ml) vs. those classified radiographically as normal to mild (31.9, 95% CI 21.1-48.1 uU/ml P = 0.03). Conclusions: Dynamic insulin testing was not performed; some normoinsulinaemic animals might have had subtle insulin dysregulation. Conclusions: Although radiographic abnormalities were present in most animals at the time of PPID diagnosis, chronic laminitis remained unrecognised by many owners. Owner awareness of laminitis increased with severity of hyperinsulinaemia and higher insulin concentrations were detected in association with more severe radiographic changes. The Summary is available in Chinese - See Supporting Information.
© 2018 EVJ Ltd.
Publication Date: 2018-06-20 PubMed ID: 29761574DOI: 10.1111/evj.12963Google Scholar: Lookup
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- Journal Article
Summary
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This research investigates the relationship between high levels of insulin (hyperinsulinaemia) and the severity of laminitis (a painful condition that affects horses’ hooves) in animals with pituitary pars intermedia dysfunction (PPID), a common hormone disorder in older horses. The study finds that not only is there a connection, but many horse owners are not aware of chronic instances of this condition.
Study Objective and Hypotheses
- The researchers conducted a cross-sectional study with two hypotheses. Firstly, they suggested that the severity of laminitis in horses suffering from PPID has direct correlation to the level of hyperinsulinaemia. Secondly, they proposed that not all horses’ owners realize their animals are suffering from chronic endocrinopathic laminitis.
Methodology
- For this study, the researchers examined serum insulin levels, laminitis history as reported by the owners, and radiographic evidence of laminitis in 38 client-owned horses diagnosed with PPID.
- Laminitis severity was categorized into four groups—nonlaminitic, mild, moderate, or severe—based on the degree of distal phalangeal rotation. The horses were also classified into three categories according to their levels of insulin—normal (50 μU/ml).
- They used one-way ANOVA, t tests, and Fisher’s exact tests for analytical purposes.
Results
- The results demonstrated that while 37% of the owners reported instances of laminitis, a higher percentage (76%) were actually identified as laminitic based on the study’s criteria.
- Animal owners were more likely to report laminitis in horses with hyperinsulinaemia, and this recognition increased with the severity of hyperinsulinaemia.
- Those horses with moderate to severe radiographic laminitis had higher mean insulin concentrations compared to those classified as having normal to mild laminitis.
Conclusions
- The study did not perform dynamic insulin testing, so some animals that appeared to be normoinsulinaemic might have had subtle insulin dysregulation.
- Despite radiographic abnormalities being present in most animals at the time of PPID diagnosis, chronic laminitis remained unrecognised by many owners.
- Overall, the study concluded that the awareness of horse owners increased with the severity of hyperinsulinaemia. It also established that higher insulin concentrations were found in association with more severe radiographic changes.
Cite This Article
APA
Tadros EM, Fowlie JG, Refsal KR, Marteniuk J, Schott HC.
(2018).
Association between hyperinsulinaemia and laminitis severity at the time of pituitary pars intermedia dysfunction diagnosis.
Equine Vet J, 51(1), 52-56.
https://doi.org/10.1111/evj.12963 Publication
Researcher Affiliations
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, Michigan, USA.
- Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA.
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, Michigan, USA.
- Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA.
- Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, USA.
MeSH Terms
- Adrenocorticotropic Hormone / blood
- Analysis of Variance
- Animals
- Cross-Sectional Studies
- Female
- Foot Diseases / diagnostic imaging
- Foot Diseases / pathology
- Foot Diseases / veterinary
- Hoof and Claw / pathology
- Horse Diseases / diagnosis
- Horse Diseases / pathology
- Horse Diseases / physiopathology
- Horses
- Hydrocortisone / blood
- Hyperinsulinism / complications
- Hyperinsulinism / veterinary
- Insulin / blood
- Pituitary Diseases / complications
- Pituitary Diseases / diagnosis
- Pituitary Diseases / physiopathology
- Pituitary Diseases / veterinary
- Pituitary Gland, Intermediate / physiopathology
- Severity of Illness Index
Grant Funding
- Boehringer Ingelheim Vetmedica, Inc.
Citations
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