Context: Tight glucose control (TGC) reduces morbidity and mortality in patients undergoing elective cardiac surgery, but only limited data about its optimal timing are available to date.
Objective: The purpose of this article was to compare the effects of perioperative vs postoperative initiation of TGC on postoperative adverse events in cardiac surgery patients.
Design: This was a single center, single-blind, parallel-group, randomized controlled trial.
Settings: The setting was an academic tertiary hospital.
Participants: Participants were 2383 hemodynamically stable patients undergoing major cardiac surgery with expected postoperative intensive care unit treatment for at least 2 consecutive days.
Intervention: Intensive insulin therapy was initiated perioperatively or postoperatively with a target glucose range of 4.4 to 6.1 mmol/L.
Main outcome measures: Adverse events from any cause during postoperative hospital stay were compared.
Results: In the whole cohort, perioperatively initiated TGC markedly reduced the number of postoperative complications (23.2% vs 34.1%, 95% confidence interval [CI], 0.60-0.78) despite only minimal improvement in glucose control (blood glucose, 6.6 ± 0.7 vs 6.7 ± 0.8 mmol/L, P < .001; time in target range, 39.3% ± 13.7% vs 37.3% ± 13.8%, P < .001). The positive effects of TGC on postoperative complications were driven by nondiabetic subjects (21.3% vs 33.7%, 95% CI, 0.54-0.74; blood glucose 6.5 ± 0.6 vs 6.6 ± 0.8 mmol/L, not significant; time in target range, 40.8% ± 13.6% vs 39.7% ± 13.8%, not significant), whereas no significant effect was seen in diabetic patients (29.4% vs 35.1%, 95% CI, 0.66-1.06) despite significantly better glucose control in the perioperative group (blood glucose, 6.9 ± 1.0 vs 7.1 ± 0.8 mmol/L, P < .001; time in target range, 34.3% ± 12.7% vs 30.8% ± 11.5%, P < .001).
Conclusions: Perioperative initiation of intensive insulin therapy during cardiac surgery reduces postoperative morbidity in nondiabetic patients while having a minimal effect in diabetic subjects.
Trial registration: ClinicalTrials.gov NCT01548963.