Validation of HOMA2S in acute phase of myocardial infarction, based on euglycemic-hyperinsulinemic clamp

Abstract

Introduction: Insulin sensitivity (IS) has an important role in endothelial function, thrombogenesis and therefore the risk of further cardiovascular events in stress situations such as myocardial infarction (MI). The Homeostasis Modeling Assessment (HOMA2S) allows to measure the IS of more practical compared to the euglycemic-hyperinsulinemic clamp - considered the gold standard method in the evaluation of SI. But the HOMA2S has been validated only for situations of metabolic stability, but not for stress situations. Objectives: The study aims to validate the HOMA2S to situations of metabolic instability such as the acute phase of MI. Methods: We performed hyperinsulinemic-euglycemic clamps in 40 nondiabetic patients from the prospective cohort Brazilian Heart Study (BHS), admitted within the first 24 hours of symptoms of ST-segment elevation MI. The clamps were performed at the second (D2) (n = 40) and sixth day (D6) (n = 16) after MI. In addition, basal (12 hour-fasting) blood samples on D2 and D6 were used to evaluated blood glucose levels, insulinaemia and subsequently calculate HOMA2S. Statistical analysis: For the comparative analysis between HOMA2S and IS determined by clamp (ISclamp), linear regressions and ROC curve were performed. Furthermore, we used Bland-Altman analysis to determine whether there was systematic errors. Results: Linear regressions showed statistical significance between ISclamp and HOMA2S in D2 (R = 0.47, p = 0.004), HOMA2S in D6 (R = 0.54, p = 0.003) and the combined HOMA2S in D2 and D6 (R = 0.52, p <0.001). The Bland-Altman graph showed no significant systematic bias. In the ROC curves for discrimination of ISclamp in D2 and D6 above the 66th percentile, we obtained an area under the curve of 0.80 (95% CI 0.68 to 0.92, p <0.001). In the best cutoff point of the ROC curve, for a sensitivity of 75% we obtained a specificity of 83%. Conclusion: Based on the comparison with the euglycemic-hyperinsulinemic clamp, the HOMA2S can also be used in the acute phase of MI as a reliable marker of IS.