Historically a rare disease, type 2 diabetes mellitus should be considered an important differential diagnosis in mature or elderly horses and ponies with weight loss and excessive drinking and urinating, advised a team of veterinarians led by Andy Durham, BSc, BVSc, CertEP, DEIM, Dipl. ECEIM, MRCVS. The team consisted of vets from England, Ireland, and the U.S.
Diabetes mellitus (DM) is a chronic elevation of blood glucose (sugar) levels. The hormone insulin, produced by the pancreas, usually maintains blood-sugar levels within very tight limits. Diabetes results due to defects in insulin secretion, action, or both.
According to Durham et al., type 2 DM (T2DM) results from a gradual onset of insulin resistance and pancreatic β cell failure (i.e., inability to produce insulin) that is only rarely diagnosed in equine practice.
Considering the recent increased awareness of insulin resistance and equine metabolic syndrome in horses, the veterinarians hypothesized that T2DM might be more common than currently speculated.
Using a specific and quantitative method to assess insulin sensitivity and pancreatic β cell response called a MINOMOD analysis of the intravenous glucose tolerance test (FSIGTT) in three horses, the veterinarians diagnosed all three with end-stage T2DM. The horses were then treated with a multimodal treatment approach that included dietary modification, metformin, glibenclamide, and/or pergolide.
Treatment successfully restored normal blood glucose levels in all three cases. Durham and co-workers concluded that "T2DM in horses may be more common than generally considered. In some cases individuals may respond