Background—Derangement of glucose metabolism after surgery is not specific to patients with diabetes mellitus. We investigated the effect of different degrees of blood glucose control (BGC) on clinical outcomes after cardiac surgery.

Methods and Results—We analyzed 8727 adults operated on between April 1996 and March 2004. The highest blood glucose level recorded over the first 60 hours postoperatively was used to classify patients as having good (<200 mg/dL), moderate (200 to 250 mg/dL), or poor (>250 mg/dL) BGC; 7547 patients (85%) had good, 905 (10%) had moderate, and 365 (4%) had poor BGC. Patients with inadequate BGC were more likely to present with advanced New York Heart Association class, congestive heart failure, hypertension, renal dysfunction, and ejection fraction <50% (P0.001). We found that 52% of patients with poor, 31% with moderate, and 8% with good BGC had diabetes mellitus. Inadequate BGC, but not diabetes mellitus (P=0.79), was associated with in-hospital mortality (good, 1.8%; moderate, 4.2%; poor, 9.6%; adjusted odds ratio: poor versus good BGC, 3.90 [95% confidence interval, 2.47 to 6.15]; moderate versus good BGC, 1.68 [95% confidence interval, 1.25 to 2.25]). Inadequate BGC also was associated with postoperative myocardial infarction (eg, odds ratio, poor versus good BGC: 2.73 [95% confidence interval, 1.74 to 4.26]) and with pulmonary and renal complications in patients without known diabetes mellitus (eg, odds ratio, poor versus good BGC: 2.27 [95% confidence interval, 1.65 to 3.12] and 2.82 [95% confidence interval, 1.54 to 5.14] respectively).

Conclusions—More than 50% of patients with moderate to poor BGC after cardiac surgery were not previously identified as diabetic. Inadequate postoperative BGC is a predictor of in-hospital mortality and morbidity.