INS and Hyperglycemia: The main findings of the current study are that (1) highly prevalent hyperglycemia is caused by an insufficient increase in insulin secretion to compensate for the prevailing IR, (2) hyperglycemia persists as classified as prediabetes or diabetes in a large proportion of patients despite improvement in their IS, and (3) REE is high during the acute phase and reverts to predicted levels already after 3 months of follow-up.