989-P: The Effect of Continuous Glucose Monitoring on Postoperative Glucose Control in People with Type 2 Diabetes Mellitus Undergoing Coronary Artery Bypass Grafting—A Randomized Clinical Trial

Introduction & Objective: Effective glycemic control following cardiac surgery improves overall clinical outcomes, and continuous glucose monitoring (CGM) is a valuable tool in achieving this objective. We investigated the effect of CGM on postoperative glycemic control in patients with diabetes after coronary artery bypass grafting (CABG).

Method: In this randomized clinical trial involving adults with type 2 diabetes undergoing CABG, all participants utilized real-time CGM (Dexcom G6) after scheduled CABG, and received a basal bolus insulin regimen. The subjects were randomly assigned to either a test group utilizing CGM for glycemic control, or a control group with blinded CGM measures, relying on point-of-care measures. The primary outcome was the percentage of time in range (TIR) of blood glucose between 70-180 mg/dL, as measured by CGM.

Results: Of total 96 subjects, 49 were in the test group and 47 in the control group. CGM was applied for 5.9 ± 2.0 days. Participants had a mean age of 68.9 ± 9.3 years, and baseline glycated hemoglobin was 7.2 ± 0.9 %. The least squares (LS) mean ± standard error of TIR was 58.9 ± 2.7%, 50.2 ± 2.8% in the test and control group, respectively. TIR was significantly higher in the test group than in the control group when adjusted with age, sex, body mass index, and baseline glycated hemoglobin (LS mean difference, 8.3%; 95% confidence interval, 0.4-16.3; p=0.041). Time above range and mean glucose levels were also significantly lower in the test group than in the control group. No differences in time below range, coefficient of variation, and hypoglycemic event rate were observed between the two groups.

Conclusion: In this randomized clinical trial, Dexcom G6 CGM has enhanced glycemic control without increasing the risk of hypoglycemia. Given the benefits of effective glycemic control on perioperative outcomes, CGM may be helpful in managing type 2 diabetes after CABG.