Diabetes and stress hyperglycemia in the intensive care unit: outcomes after cardiac surgery

Background: Hyperglycemia is common in the post-cardiac surgery population and has been associated with increased mortality rates, surgical length of stay, and infection rates. Although hospitalized patients with diabetes are known to have more complications, recent studies in various hospital settings have reported worse outcomes in patients with stress hyperglycemia than in those with diabetes. Aim: The primary objective of this study was to analyze 30- and 90-day mortality rates in post-cardiac surgery patients with stress hyperglycemia and diabetes who were managed to achieve similar moderate blood glucose goals using the University of Michigan Hospital (Ann Arbor, MI) insulin protocol between 2005 and 2008. The secondary outcomes were rates of postoperative complications, including hypoglycemia. Methods: A standardized glucose management program was followed to treat all patients in the cardiac intensive care unit, with a blood glucose goal of 100 to 140 mg/dL. Data from 1973 patients with either diabetes or stress hyperglycemia were analyzed to identify associations between mean postoperative blood glucose levels and mortality, incidence of hypoglycemia, and complication rates. Results: Mortality rates did not differ between patients with diabetes and stress hyperglycemia (3.4 and 2.3%; P = 0.2). Rates of severe hypoglycemia were low (1%) for both groups and were not associated with an increase in mortality (P = 0.95). Other complication rates were similar between patients with diabetes and stress hyperglycemia. Conclusion: Maintaining a blood glucose range between 100 to 140 mg/dL in post-cardiac surgery patients was associated with a low mortality rate, low risk of hypoglycemia, and with complications rates that were similar in patients with diabetes and stress hyperglycemia.