Effects of moderate intensity glycemic control after cardiac surgery

The impact of intensive insulin therapy on the clinical outcomes of hospitalized patients is highly controversial. We used a protocol based on dynamic insulin administration targeted to achieve moderately tight glycemic control and tested its impact on clinical outcomes after cardiac surgery.

Patients with diabetes mellitus or random blood glucose greater than 150 mg/dL were treated in the intensive care unit with intravenous insulin, followed by a multi-injection protocol consisting of 4 glargine/aspart insulin injections in the ward, with a glycemic target of 110 to 150 mg/dL. The study cohort (n = 410) consisted of consecutive patients undergoing cardiothoracic surgery. Control patients (n = 207) were admitted during the first 8 months and treated according to standard of care. The intervention group of patients (n = 203) were operated on during the following 8 months. The main outcome measures were glycemic control and the rate of postsurgery infections.

During the intervention, mean blood glucose ± SD was 151 ± 19 mg/dL and 157 ± 32 mg/dL in the intensive care unit and ward, respectively, versus 166 ± 27 mg/dL and 184 ± 46 mg/dL during the control period (p < 0.0001). The incidence of hypoglycemia (blood glucose less than 60 mg/dL) was low and similar in the two groups (2.5% control versus 3% intervention). Intensive insulin treatment decreased the risk for infection from 11% to 5% (56% risk reduction, p = 0.018), mainly by reducing the incidence of graft harvest site infection (6.9% versus 2.5%, p = 0.034). The incidence of atrial fibrillation after coronary artery bypass graft surgery decreased from 30% to 18% (39% risk reduction; p = 0.042).

Moderate-intensity dynamic blood glucose control after cardiac surgery is effective and safe, and is associated with improved clinical outcomes.