Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)BACKGROUND: The decrease of insulin sensitivity (IS) during myocardial infarction (MI) is strongly associated with increased morbidity and mortality. Recent data suggest that in individuals under stable conditions, high-density lipoprotein (HDL) may improve IS. To date, the role of HDL in the modulation of IS in acute metabolic stress conditions such as MI remains unknown. OBJECTIVE: To explore the association between plasma HDL-C and the change in IS during the acute phase of MI. METHODS: Consecutive nondiabetic patients with ST-segment elevation MI (n = 22) underwent direct measurement of IS through the euglycemic hyperinsulinemic clamp on the first morning and on the fifth day after onset of MI. Patients were grouped according to HDL-C levels at admission above and below the median value (35 mg/dL). RESULTS: At admission, there was no significant difference in baseline IS index, clinical, anthropometric, or treatment characteristics between low and high HDL groups. Between admission and fifth day, there was a decrease of 8% in IS index in the low HDL group and an 11% increase in the high HDL group (P = .001 for intragroup and P = .012 for intergroup difference). This difference remained significant after we controlled for the sex, age, waist circumference, triglycerides, baseline IS index, and statin dose during hospitalization. CONCLUSION: This is the first study to provide evidence that plasma levels of HDL-C are strongly associated with the recovery rate of IS during the acute phase of MI. (C) 2013 National Lipid Association. All rights reserved.712428Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [308550/2010-2]