The role of hyperglycemia in acute illness: supporting evidence and its limitations.

Hyperglycemia is common in acutely ill hospitalized patients and has been linked to poor outcomes, independent of pre-existing diabetes. Correction of hyperglycemia has been shown to decrease morbidity and mortality; however, establishing evidence-based guidelines has been challenging because insulin intervention studies have varied in the questions they have addressed, glucose levels studied, feeding regimen, and quality of methodology. This article reviews the findings and limitations of recent intervention studies that have addressed treatment of inpatient hyperglycemia with intravenous insulin infusion therapy. Discussion of underlying causes of hospital-related hyperglycemia and mechanisms explaining the deleterious effects of hyperglycemia and improved outcomes with insulin intervention are described. Current guidelines from various professional organizations recommend treatment of inpatient hyperglycemia, although exact glycemic targets and identification of which patient subsets will receive greatest benefit from glucose lowering remain an area of ongoing research.