Intensive versus conservative glycaemic control in patients undergoing coronary artery bypass graft surgery: a protocol for systematic review and meta-analysis of randomized controlled trials

Background Coronary artery bypass graft (CABG) surgery has become the most common surgical procedure among all cardiac surgeries. Hyperglycaemia and hypoglycaemia occur frequently during this type of surgery and are associated with a variety of postoperative outcomes. Therefore, intraoperative glycaemic control is an important issue for patients undergoing CABG surgery. This systematic review and meta-analysis aim to evaluate the effects of different intraoperative glycaemic control strategies on postoperative outcomes. Methods We will perform a systematic review and meta-analysis of randomized controlled trials (RCTs) according to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Relevant studies will be searched in the Medline, Embase, Cochrane Library and Web of Science databases. Two independent reviewers will conduct study selection, data extraction, risk of bias assessment and quality of evidence assessment. The primary outcome will be postoperative mortality, and the secondary outcomes will include time on a ventilator in the intensive care unit (ICU), incidence of postoperative myocardial infarction (MI), incidence of postoperative atrial fibrillation (AF), rate of postoperative infection, incidence of acute kidney failure (AKF), length of stay (LOS) in the ICU, and LOS in the hospital. χ2 (Cochran Q) and I2 methods will be used to assess statistical heterogeneity. Sensitivity analysis will also be performed to explore the source of clinical heterogeneity, and subgroup analyses will be performed to detect possible heterogeneity of the results. Review Manager (RevMan) 5.4 will be used for data management and statistical analysis. The Cochrane risk-of-bias tool 2.0 and GRADEpro will be applied for risk of bias and quality assessment of the evidence. Discussion We assume that intensive glycaemic control in patients undergoing CABG will reduce postoperative mortality and complications, which seriously compromise a patient’s quality of life and may even cause premature death. To address limitations in our study, corresponding methodologies will be adopted to optimize the results as much as possible. The results of our study are expected to provide strong evidence supporting the relationship between intensive intraoperative glycaemic control strategies and the reduction of postoperative complications in patients undergoing CABG surgery. Systematic review registration PROSPERO CRD42021240841.