Glycemic control in the critically ill: What have we learned since NICE-SUGAR?

Since publication of the Normoglycemia in Intensive Care Evaluation - Survival Using Glucose Algorithm Regulation trial in 2009, demonstrating increased 90-day mortality in a large cohort of critically ill patients treated with the intensive, rather than moderate blood glucose (BG) target, enthusiasm has dampened for 'tight glucose control' in intensive care units. Nevertheless, a burgeoning literature has clarified limitations of the interventional trials of intensive insulin therapy in the critically ill and explored key clinical aspects of glycemic control in this population. This review provides an overview of the last 6 years of research in this field. Topics include advances in understanding the domains of glycemic control - hyperglycemia, hypoglycemia and glucose variability; the role of diabetic status in modulating the relationship of these domains of control to mortality; the importance of premorbid glucose control in patients with diabetes; the central role that measurement frequency has in determining success in achieving desired BG control and, finally, new data exploring time in targeted BG range, a potentially 'unifying' metric.