Comparison of fasted basal insulin with the combined glucose-insulin test in horses and ponies with suspected insulin dysregulation

Olley, R. B.; Carslake, Harry; Ireland, J.L.; McGowan, Catherine

doi:10.1016/j.tvjl.2019.105351

Cited by 18 publications

(22 citation statements)

References 21 publications

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“…The chemiluminescent assay has found to give lower readings for endogenous equine insulin compared to the species optimized equine ELISA used in the present study [27]. The higher sensitivity for FI in the present study may reflect the study population with an evenly distributed wide range of IS with relatively fewer sampling points around the cut-off level for FI compared with the study by Olley and coworkers [15]. Compared to FI, the proxies gave similar results for predicting IR with sensitivities of 79 to 91 % and specificities varying between 85 to 96 %.…”

Section: Discussioncontrasting

confidence: 61%

“…In a recent study, the authors demonstrated that the poor sensitivity for FI was related to the cut-off value used rather than FI being an intrinsically inappropriate test [15]. By reducing the commonly suggested cut-off value of 20 µIU/mL to 5.2 µIU/mL for FI, the sensitivity for the diagnosis of ID increased from 15 to 63 % without a major impact on the specificity, which decreased from 100 to 87 % [15]. In comparison, the cut-off value for FI in the present study was 9.5 µIU/mL with sensitivity of 91 % and specificity of 85 %.…”

Section: Discussionmentioning

confidence: 99%

“…However, use of FI to diagnose ID has been shown to have poor sensitivity [16]. On the other hand, a recent study concluded that FI had adequate sensitivity and specificity when using lower cut-off values than previously suggested [15].…”

Section: Introductionmentioning

confidence: 94%

“…Several proxies have been used in equine research [11,12] but whether these proxies provide better information about the patients' IS or β-cell response compared to the insulin and glucose concentrations they are calculated from has not yet been established. Insulin concentrations are influenced by feeding [13,14] and therefore measurement of FI has been recommended to standardize testing [15]. However, use of FI to diagnose ID has been shown to have poor sensitivity [16].…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of fasting plasma insulin and proxy measurements to assess insulin sensitivity in horses

et al. 2021

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Background Proxies are mathematical calculations based on fasting glucose and/or insulin concentrations developed to allow prediction of insulin sensitivity (IS) and β-cell response. These proxies have not been evaluated in horses with insulin dysregulation. The first objective of this study was to evaluate how fasting insulin (FI) and proxies for IS (1/Insulin, reciprocal of the square root of insulin (RISQI) and the quantitative insulin sensitivity check index (QUICKI)) and β-cell response (the modified insulin-to-glucose ratio (MIRG) and the homeostatic model assessment of β-cell function (HOMA-β)) were correlated to measures of IS (M index) using the euglycemic hyperinsulinemic clamp (EHC) in horses with insulin resistance (IR) and normal IS. A second objective was to evaluate the repeatability of FI and proxies in horses based on sampling on consecutive days. The last objective was to investigate the most appropriate cut-off value for the proxies and FI. Results Thirty-four horses were categorized as IR and 26 as IS based on the M index. The proxies and FI had coefficients of variation (CVs) ≤ 25.3 % and very good reliability (intraclass correlation coefficients ≥ 0.89). All proxies and FI were good predictors of the M index (r = 0.76–0.85; P < 0.001). The proxies for IS had a positive linear relationship with the M index whereas proxies for β-cell response and FI had an inverse relationship with the M index. Cut-off values to distinguish horses with IR from horses with normal IS based on the M index were established for all proxies and FI using receiver operating characteristic curves, with sensitivity between 79 % and 91 % and specificity between 85 % and 96 %. The cut-off values to predict IR were < 0.32 (RISQI), < 0.33 (QUICKI) and > 9.5 µIU/mL for FI. Conclusions All proxies and FI provided repeatable estimates of horses’ IS. However, there is no advantage of using proxies instead of FI to estimate IR in the horse. Due to the heteroscedasticity of the data, proxies and FI in general are more suitable for epidemiological studies and larger clinical studies than as a diagnostic tool for measurement of IR in individual horses.

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Section: Discussioncontrasting

confidence: 61%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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Evaluation of fasting plasma insulin and proxy measurements to assess insulin sensitivity in horses

et al. 2021

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“…In horses, baseline insulin and glucose concentrations are recommended as a screening test for metabolic syndrome (high specificity), but the sensitivity is not adequate for ruling out EMS [39]. Newer research suggests that the cut-off values for suspected insulin dysregulation/resistance in horses might be lower than initially anticipated [40,41]. Furthermore, glucose and insulin concentrations in donkeys may be altered by previous transportation [42].…”

Section: Diagnostic Testing For Insulin Dysregulationmentioning

confidence: 99%

Pituitary Pars Intermedia Dysfunction and Metabolic Syndrome in Donkeys

Gehlen

Schwarz²,

Bartmann

et al. 2020

Animals

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Appropriate medical care for donkeys is challenging despite being important working animals in non-industrialized countries and pets in first world countries. Although the same principles of diagnosis and therapy as in horses are commonly applied, there are differences in reference values and physiologic reaction to dynamic tests. However, donkeys seem to suffer from typical equine diseases, such as metabolic syndrome and pituitary pars intermedia dysfunction (PPID). Asinine metabolic syndrome (AMS) comprises obesity, insulin dysregulation, and laminitis. The principles of diagnosis are similar to horses. Donkey-specific reference ranges for insulin and glucose have been evaluated previously. Examinations regarding dynamic testing revealed differences in the intravenous glucose tolerance test and the combined insulin tolerance test compared to horses. The therapy of AMS is based mainly on weight loss and exercise. There are conflicting data regarding the incidence of PPID in donkeys. Laminitis and hypertrichosis were described as the main clinical signs. Species-specific and seasonal reference ranges were defined to diagnose PPID in donkeys. Furthermore, the dexamethasone suppression test, the thyrotropin releasing hormone (TRH) test and the combined dexamethasone suppression/TRH test were evaluated. Pergolide is commonly recommended for treatment.

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Comparison of Two Diagnostic Methods to Detect Insulin Dysregulation in Horses Under Field Conditions

Wollenberg

Vandendriessche

Maanen

et al. 2020

Journal of Equine Veterinary Science

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Comparison of fasted basal insulin with the combined glucose-insulin test in horses and ponies with suspected insulin dysregulation

Cited by 18 publications

References 21 publications

Evaluation of fasting plasma insulin and proxy measurements to assess insulin sensitivity in horses

Evaluation of fasting plasma insulin and proxy measurements to assess insulin sensitivity in horses

Pituitary Pars Intermedia Dysfunction and Metabolic Syndrome in Donkeys

Comparison of Two Diagnostic Methods to Detect Insulin Dysregulation in Horses Under Field Conditions

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