Diagnosis of equine endocrinopathies: The value of measuring blood glucose during an oral glucose test.

This research paper analyzes the effectiveness of using blood glucose measurements during an Oral Glucose Test (OGT) to diagnose horse diseases related to endocrine system dysfunction, such as insulin dysregulation and pituitary pars intermedia dysfunction (PPID).

General aim of the research

• This study aimed to determine if changes in blood glucose levels during an OGT can assist in diagnosing insulin dysregulation (ID) or pituitary pars intermedia dysfunction (PPID) in horses.
• The researchers analyzed various indicators, such as serum insulin and plasma ACTH concentrations, clinical observations, age, sex, breed type, and the dose utilized in the test for accurate diagnosis.

Research methodology

• The researchers used a sample of 149 animals – horses, miniature horses, and ponies – all of which had undergone an OGT between 2015 and 2021.
• The animals were diagnosed as either metabolically healthy, insulin-dysregulated, afflicted with PPID, or possessing both endocrinopathies.
• The researchers observed the increase in blood glucose levels as a response to the OGT, aiming to find a correlation with various factors influencing disease diagnosis.

Research findings

• The mean increase in blood glucose levels was found to be 3.41 ± 0.21 mM and showed a weak positive correlation with the increase in serum insulin concentration, body condition score (BCS), and cresty neck score (CNS).
• Higher blood glucose concentration was observed in miniature horses when compared to full-sized horses.
• Different responses were observed in metabolically healthy animals versus those afflicted with ID or both endocrine diseases, with the latter two groups showing a larger increase in blood glucose levels during an OGT.
• The test dose of dextrose also influenced the blood glucose levels response, with higher doses giving larger responses.

Research conclusion

• The results showed significant variability, suggesting that monitoring blood glucose responses to an OGT may not be effective as a standalone diagnostic indicator for ID or PPID.
• However, the correlation found between changes in blood glucose level and CNS implies that this test may still be viable in tandem with other clinical observations for diagnosing ID, demonstrating the need for comprehensive and multi-pronged approaches in diagnosing equine endocrine disorders.