Dataset DOI: 10.5061/dryad.fbg79cpbb

Description of the data and file structure

180 sport horses presenting for orthopaedic evaluation at a university hospital (N=140) or local farms (N=40) were tested for ID using OST (0.15 mL/kg light corn syrup). Morphometric data were collected, and baseline serum leptin and adiponectin concentrations were measured. Insulin concentrations were measured using the validated fluorescence enzyme immunoassay (FEIA) and a stall-side lateral flow assay (LFA). ID was diagnosed if FEIA insulin measured >20 mIU/mL at T0 or >30 mIU/mL at T60/T90. Factors associated with ID were assessed using a mixed effects binary logistic regression model. Assay agreement was assessed using Pearson’s correlation coefficient and Bland-Altman plot. Receiver operator characteristic curve analysis was performed to determine diagnostic cut-offs for LFA.

Files and variables

File: SupplementalFile1-IDPrevalence.xlsx

Description:  Data from all 180 enrolled horses. Abbreviations used: H-hospital, F-field, M-mare, G-gelding, S-stallion, QH-quarter horse, BCS-body condition score, CNS-cresty neck score, BCI-body condition index, PPID-pituitary pars intermedia dysfunction, FEIA-fluorescence enzyme immunoassay, LFA-lateral flow assay, Y-yes, N-no. Insulin dysregulation defined as FEIA insulin > 20 mIU/mL at T0, or >30 mIU/mL at T60 or T90. PPID status reported by owners.

Definitions for included variables:

• Horse ID: Categorical; horse identification number assigned by medical records system to anonymize names of study participants
• Field/Hospital: Binary categorical variable denoting site at which testing was performed. Horses tested at local performance farms denoted by “F” for field, and horses tested in hospital denoted by “H”
• Age (years): Continuous variable; age of the horse provided by owner in years
• Sex: Categorical; sex of the horse, abbreviated as “M” for mare (intact female), “S” for stallion (intact male), and “G” for gelding (castrated male)
• Breed: Categorical; breed of horse provided by owner, “QH/Paint” denotes Quarter Horse or Paint breed horses.
• Discipline: Categorical; the riding discipline for which the horse is primarily used as provided by the owner
• Weight (kg): Continuous variable; weight of the horse in kilograms; for horses in the “hospital” population this was determined by digital scale, and for horses in the “field” population this was determined using a weight tape designed for horses
• BCS: Categorical ordinal on a scale of 1-9; BCS defined as body condition score, determined by the same veterinarian for all horses using the Henneke body condition scoring scale
• CNS: Categorical ordinal on a scale of 0-5; CNS defined as cresty neck score, determined by the same veterinarian for all horses using the cresty neck score first described by Carter et al
• BCI: Continuous; BCI defined as body condition index, determined using a formula described by Potter et al using the height, length, neck circumference, heart girth circumference, and belly circumference of the horse; all measurements performed by the same veterinarian for all horses in the study
• Hospital acclimation time (hours): Continuous; the amount of time the horse was allowed to acclimate to the hospital environment prior to the initiation of endocrine testing
• Systemic medications: Categorical; owner-reported medications that the horse was receiving at time of study enrollment
• PPID: Binary categorical; PPID defined as pituitary pars intermedia dysfunction, owners were asked to respond “yes” (Y) or “no” (N) to whether or not their horse had been previously diagnosed with this condition
• Leptin (ng/mL): Continuous; the concentration of leptin, a hormone produced by adipocytes, in ng/mL; measurement was performed on serum samples obtained following a minimum 3 hour fasting period, and using a radioimmunoassay previously validated for use in horses
• Adiponectin (ug/mL): Continuous; the concentration of adiponectin, a hormone produced by adipocytes, in ug/mL; measurement was performed on serum samples obtained following a minimum 3 hour fasting period, and using an immunoturbidometric assay previously validated for use in horses
• Leptin/adiponectin ratio: Continuous; the ratio of leptin to adiponectin, measured as described above
• FEIA T0 insulin (uIU/mL): Continuous; the concentration of insulin in uIU/mL; measurement was performed on serum samples obtained following a minimum 3 hour fasting period, and using a fluorescence enzyme immunoassay previously validated for use in horses
• FEIA T60 insulin (uIU/mL): Continuous; the concentration of insulin in uIU/mL; measurement was performed on serum samples obtained 60 minutes after administration of a 0.15 mL/kg dose of light corn syrup administered orally and using a fluorescence enzyme immunoassay previously validated for use in horses
• FEIA T90 insulin (uIU/mL): Continuous; the concentration of insulin in uIU/mL; measurement was performed on serum samples obtained 90 minutes after administration of a 0.15 mL/kg dose of light corn syrup administered orally and using a fluorescence enzyme immunoassay previously validated for use in horses
• LFA T0 insulin (uIU/mL): Continuous; the concentration of insulin in uIU/mL; measurement was performed on whole blood samples obtained following a minimum 3 hour fasting period, and using a lateral flow assay (LFA) previously validated for use in horses; the LFA has a lower limit of detection of 20 uIU/mL and all values below that lower limit of detection are recorded as <20.0
• LFA T60 insulin (uIU/mL): Continuous; the concentration of insulin in uIU/mL; measurement was performed on whole blood samples obtained 60 minutes after administration of a 0.15 mL/kg dose of light corn syrup administered orally and using a lateral flow assay (LFA) previously validated for use in horses; the LFA has a lower limit of detection of 20 uIU/mL and all values below that lower limit of detection are recorded as <20.0
• LFA T90 insulin (uIU/mL): Continuous; the concentration of insulin in uIU/mL; measurement was performed on whole blood samples obtained 60 minutes after administration of a 0.15 mL/kg dose of light corn syrup administered orally and using a lateral flow assay (LFA) previously validated for use in horses; the LFA has a lower limit of detection of 20 uIU/mL and all values below that lower limit of detection are recorded as <20.0
• Insulin dysregulation: Binary categorical variable; classified as “yes” (Y) if FEIA T0 insulin was >20 uIU/mL or FEIA T60/T90 insulin >30 uIU/mL; classified as “no” (N) if these conditions were not met

Code/software

Microsoft Excel or equivalent

Access information

Other publicly accessible locations of the data:

• Supplemental File 1 in open access manuscript - EVJ

Data was derived from the following sources:

• Original experimental data