Changing glucose control target and risk of surgical site infection in a Southeast Asian population

Objective: Hyperglycemia is associated with surgical site infection and mortality in cardiac surgical patients. There is overriding evidence that glycemic control improves morbidity and mortality. However, the optimal glucose range in these patients remains controversial. Intensive glucose control can lead to mortality among critically ill adults because of episodic, moderate hypoglycemia. Therefore, we examined the effect of different glucose target control on the incidence of surgical site infection in our prospective cohort of diabetic and nondiabetic patients undergoing coronary artery bypass grafting. Methods: Data from 1442 patients who underwent elective coronary artery bypass grafting at a tertiary heart center in Singapore from 2009 to 2011 were obtained. The first glucose level on arrival in the cardiothoracic intensive care unit was set at 4 to 8 mmol/L in 2009 and 2010 and 4 to 10 mmol/L in 2011. Glucose control was achieved with intravenous insulin infusion with a strict glucose monitoring protocol. Clinical covariates were analyzed, with surgical site infection as the primary outcome. Results: The majority of patients presenting for coronary artery bypass grafting were male, Chinese, and diabetic. Diabetic patients had significantly higher glucose levels on arrival in the cardiothoracic intensive care unit. The change in target glucose control was independently associated with an increase in surgical site infection (odds ratio, 2.280; 95% confidence interval, 1.250-4.162; P = .007). Subgroup analysis revealed that unlike in nondiabetic patients, a less stringent target was independently associated with a significant increase in surgical site infection incidence from 2.2% to 6.9% for the diabetic patients (odds ratio, 3.131; 95% confidence interval, 1.431-6.851; P = .004). Conclusions: A target blood glucose of less than 8 mmol/L was associated with a lower incidence of surgical site infection in diabetic patients presenting for elective coronary artery bypass grafting in the local Southeast Asian population.