Early postoperative glucose control predicts nosocomial infection rate in diabetic patients

Abstract

Objectives: To determine the relationship between perioperative glucose control and postoperative nosocomial infection rate in 100 consecutive diabetic patients undergoing elective surgery. Design and Patients: One hundred initially uninfected diabetic patients undergoing elective surgery were prospectively monitored for perioperative glucose control and postoperative nosocomial infection rate. Glucose control was determined by the attending surgeon or diabetologist. Setting: A large tertiary care hospital that serves as the in-patient facility for a local diabetes center. Main Outcome Measures: All patients were screened for infection preoperatively. Only initially uninfected patients were enrolled, and all patients received perioperative antibiotic coverage. Perioperative glucose control and postoperative nosocomial infection rate were monitored prospectively. APACHE H scores were determined on all patients. Patients were stratified into two groups: those with relatively 'good' perioperative glucose control (all values ≤220 mg/dL) and those with 'poor' control (at least one value >220 mg/dL). Contingency tables were generated, comparing nosocomial infection rates us perioperative glucose control. Correlation coefficients between APACHE II score and maximum and mean glucose values were also determined. Results: A serum glucose >220 mg/dL on postoperative day one (POD 1) was a sensitive (87.5%) but relatively nonspecific (33.3%) predictor of the later development of postoperative nosocomial infection. In patients with hyperglycemia (>220 mg/dL) on POD 1, the infection rate was 2.7 times that observed (31.3% vs 11.5%) in diabetic patients with all serum glucose values <220 mg/dL. When minor infection of the urinary tract was excluded, the relative risk for 'serious' postoperative infection increased to 5.7 when any POD 1 blood glucose level was >220 mg/dL. On the basis of correlation coefficients between serum glucose values and APACHE II score, only 18% of the variance in the highest serum glucose could be explained by disease severity alone. Conclusion: We conclude that diabetic patients undergoing major cardiovascular or abdominal surgery have an increased risk of infection that is further exacerbated by early postoperative hyperglycemia. The high rate of nosocomial infection observed in diabetic patients with poor glucose control suggests that hyperglycemia itself may be an independent risk factor for the development of infection. Efforts to improve perioperative glucose homeostasis in diabetic patients may reduce the incidence of nosocomial infection and thereby improve outcome.