The association of diabetes and glucose control with surgical-site infections among cardiothoracic surgery patients.

OBJECTIVE To assess the importance of diabetes, diabetes control, hyperglycemia, and previously undiagnosed diabetes in the development of surgical-site infections (SSIs) among cardiothoracic surgery patients. SETTING A 540-bed tertiary-care university-affiliated hospital. DESIGN Prospective cohort and case-control studies. PATIENTS All patients having cardiothoracic surgery between November 1998 and September 1999 were eligible for participation. One thousand patients had preoperative hemoglobin A1c determinations. Seventy-four patients with SSIs were identified. RESULTS Diabetes (odd ratio [OR], 2.76; P<.001) and postoperative hyperglycemia (OR, 2.02; P=.007) were independently associated with development of SSIs. Among known diabetics, elevated hemoglobin A1c values were not associated with a statistically significantly increased risk of infection; the mean A1c value was 8.44% among those with infections compared with 7.80% for those without (P=.09). Forty-two (6%) of 700 patients without prior diabetes history had evidence of undiagnosed diabetes; their infection rate was comparable to that of known diabetics (3/42 [7%] vs 17/300 [6%]; P=.72). An additional 30% of nondiabetics had elevated hemoglobin A1c determinations or perioperative hyperglycemia. CONCLUSIONS Postoperative hyperglycemia and previously undiagnosed diabetes are associated with development of SSIs among cardiothoracic surgery patients. Screening for diabetes and hyperglycemia among patients having cardiothoracic surgery may be warranted to prevent postoperative and chronic complications of this metabolic abnormality.