Objective: Although hyperglycemia is hypothesized to increase the short-term risk of infection, this hypothesis has not been well tested in a clinical setting. This study was designed to assess the relationship of perioperative glycemic control to the subsequent risk of infectious complications.
Research design and methods: A total of 411 adults with diabetes who underwent coronary artery surgery from 1990 to 1995 in the cardiac surgery service of an urban university hospital were included in a nonconcurrent prospective cohort study based on chart review. Perioperative glycemic control was characterized by the mean of six capillary glucose measurements taken during the 36-h interval following surgery. The major outcomes studied were infections of leg and chest wounds, pneumonia, and urinary tract infections.
Results: Mean postoperative glucose levels ranged from 121 to 352 mg/dl and were divided into quartiles: quartile 1 (121-206 mg/dl), quartile 2 (207-229 mg/dl), quartile 3 (230-252 mg/dl), and quartile 4 (253352 mg/dl). After simultaneous adjustment for age, sex, race, underlying comorbidity, acute severity of illness, and the length of the stay in the surgical intensive care unit, patients with higher mean capillary glucose readings were at increased risk of developing infections. Compared with people in the lowest quartile of postoperative glucose, those in quartiles 2 (relative odds of infection [95% CI] = 1.17 [0.57-2.40]), 3 (1.86 [0.94-3.68]), and 4 (1.78 [0.86-3.47]) were at progressively higher risk for infection (P = 0.05 for trend).
Conclusions: In patients with diabetes who undergo coronary artery surgery, postoperative hyperglycemia is an independent predictor of short-term infectious complications. Physicians should consider a glucose concentration target of < or =200 mg/dl to reduce the risk of infection.