Impact of preoperative glycometabolic status on outcomes in cardiac surgery: Systematic review and meta-analysis

J Thorac Cardiovasc Surg. 2022 Dec;164(6):1950-1960.e10. doi: 10.1016/j.jtcvs.2021.05.035. Epub 2021 Jun 1.

Abstract

Background: Historically, impaired glucose metabolism has been associated with early and late complicated clinical outcomes after cardiac surgery; however, such a condition is not specific to subjects with diabetes mellitus and involves a larger patient population.

Methods: Databases were screened (January 2000 to December 2020) to identify eligible articles; studies that evaluated the association between preoperative metabolic status, as assessed by glycosylated hemoglobin levels and clinical outcomes, were considered. The studies were stratified in thresholds by baseline glycosylated hemoglobin level (lower vs higher).

Results: Thirty studies, involving 34,650 patients, were included in the review. In a meta-analysis stratified by glycosylated hemoglobin levels, early mortality was numerically reduced in each threshold comparison and yielded the highest reductions when less than 5.5% versus greater than 5.5% glycosylated hemoglobin levels were compared (risk ratio, 0.39; 95% confidence interval, 0.18-0.84; P = .02). Comparing higher glycosylated hemoglobin threshold values yielded comparable results. Late mortality was reduced with lower levels of glycosylated hemoglobin. Low preoperative glycosylated hemoglobin was associated with the lowest risk of sternal wound infections (risk ratio, 0.50; 95% confidence interval, 0.32-0.80; P = .003 and risk ratio, 0.53; 95% confidence interval, 0.39-0.70; P < .0001) for comparisons of less than 7.5% versus greater than 7.5% and less than 7.0% versus greater than 7.0% glycosylated hemoglobin thresholds, respectively. Additionally, levels of glycosylated hemoglobin lower than 7% were associated with reduced hospital stay, lower risk of stroke/transient ischemic attack (risk ratio 0.53; 95% confidence interval, 0.39-0.70; P < .0001), and acute kidney injury (risk ratio, 0.65; 95% confidence interval, 0.54-0.79; P < .0001).

Conclusions: Lower levels of glycosylated hemoglobin in patients undergoing cardiac surgery are associated with a lower risk of early and late mortality, as well as in the incidence of postoperative acute kidney injury, neurologic complications, and wound infection, compared with higher levels.

Keywords: cardiac surgery; coronary artery bypass grafting; diabetes mellitus; glycosylated hemoglobin.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Acute Kidney Injury* / complications
  • Cardiac Surgical Procedures* / adverse effects
  • Glycated Hemoglobin / analysis
  • Humans
  • Postoperative Complications
  • Risk Factors
  • Treatment Outcome

Substances

  • Glycated Hemoglobin A