The Ohio State University, College of Veterinary Medicine, Columbus, Ohio, USA.
Can Vet J. 2022 Jun;63(6):617-626.
Insulin dysregulation is a hallmark of equine metabolic syndrome (EMS) and increases the risk for development of laminitis. Accurate diagnosis of insulin dysregulation is crucial for implementation of preventative strategies in this population. The objective was to assess the effects of dexamethasone administration on insulin and glucose dynamics in light-breed horses and assess the agreement of various diagnostic tests for insulin dysregulation [basal [insulin] (BI), oral sugar test (OST), and combined glucose-insulin test (CGIT)].
Fourteen adult light-breed horses.
Prospective, experimental study to assess insulin and glucose dynamics by performing basal insulin, OST, and CGIT before (baseline) and post-dexamethasone administration (0.08 mg/kg, PO, q24h) for 7 d. Insulin and glucose dynamics were assessed by the BI, OST, CGIT, and insulin sensitivity proxy measurements (RISQI, QUICKI, FGIR, HOMA-IR, IG) at the baseline and post-dexamethasone time points.
The OST area under the insulin and glucose curves were increased following dexamethasone treatment ( < 0.001 and < 0.01, respectively). Basal insulin, OST [insulin] at 60 min and CGIT [insulin] at 45 min were increased at the post-dexamethasone time point ( < 0.001, < 0.001, and < 0.01). Similarly, time spent in the positive glucose phase during the CGIT was longer at the post-dexamethasone time point ( < 0.001). The proxy measurements for insulin sensitivity (RISQI, QUICKI, FGIR) were decreased ( < 0.01) and the proxy measurements for insulin resistance (HOMA-IR) and β-cell function (IG) were increased after dexamethasone administration ( < 0.01). More horses were classified with following dexamethasone administration, based on the diagnostic criteria for basal insulin ( = 0.03), OST ( = 0.01), and CGIT ( < 0.01). coefficients, measuring agreement between basal insulin, OST, and CGIT, showed none to moderate agreement at the baseline time point.
Dexamethasone administration at 0.08 mg/kg, PO, q24h for 7 d worsened insulin dysregulation in adult light-breed horses based on findings of a basal insulin, OST, CGIT, and insulin sensitivity proxy measurements. There was none to moderate agreement between the basal insulin, OST, CGIT for the diagnosis of insulin dysregulation.
Horses administered dexamethasone at a dose of 0.08 mg/kg, PO, q24h for 7 d should be considered insulin dysregulation and appropriate preventative strategies should be implemented. The variability of diagnostic performance of common tests for insulin dysregulation (basal insulin, OST, CGIT) may affect clinical decisions; therefore, performing multiple tests, including proxy measurements, may improve diagnostic accuracy of insulin dysregulation.
胰岛素失调是马代谢综合征（EMS）的标志之一，增加了蹄叶炎发生的风险。准确诊断胰岛素失调对该人群实施预防策略至关重要。目的是评估地塞米松给药对轻型马胰岛素和葡萄糖动态的影响，并评估各种胰岛素失调诊断测试[基础胰岛素（BI）、口服糖耐量试验（OST）和联合血糖-胰岛素试验（CGIT）]的一致性。
14 匹成年轻型马。
前瞻性实验研究，在 7 天内每天 0.08mg/kg，PO，q24h 进行地塞米松给药前（基线）和给药后，通过进行基础胰岛素、OST 和 CGIT 来评估胰岛素和葡萄糖动态。在基线和地塞米松给药后时间点，通过 BI、OST、CGIT 和胰岛素敏感性替代测量（RISQI、QUICKI、FGIR、HOMA-IR、IG）评估胰岛素和葡萄糖动态。
地塞米松治疗后 OST 胰岛素和葡萄糖曲线下面积增加（<0.001 和<0.01）。地塞米松给药后，基础胰岛素、OST60 分钟胰岛素和 CGIT45 分钟胰岛素增加（<0.001、<0.001 和<0.01）。同样，CGIT 中阳性葡萄糖期的时间在给药后延长（<0.001）。胰岛素敏感性替代测量（RISQI、QUICKI、FGIR）降低（<0.01），胰岛素抵抗（HOMA-IR）和β细胞功能（IG）的替代测量在给予地塞米松后增加（<0.01）。根据基础胰岛素（=0.03）、OST（=0.01）和 CGIT（<0.01）的诊断标准，更多的马在接受地塞米松治疗后被分类。 ，用于测量基础胰岛素、OST 和 CGIT 之间的一致性，在基线时间点显示无到中度一致性。
轻型马每天 0.08mg/kg，PO，q24h 连续 7 天给予地塞米松，基于基础胰岛素、OST、CGIT 和胰岛素敏感性替代测量结果，会导致胰岛素失调恶化。基础胰岛素、OST、CGIT 用于诊断胰岛素失调的一致性无到中度。
每天 0.08mg/kg，PO，q24h 给予地塞米松 7 天的马匹应被视为胰岛素失调，应实施适当的预防策略。常见胰岛素失调诊断测试（基础胰岛素、OST、CGIT）的诊断性能的变异性可能会影响临床决策；因此，进行包括替代测量在内的多项测试可能会提高胰岛素失调的诊断准确性。
