Glycated Hemoglobin and the Risk of Sternal Wound Infection After Adult Cardiac Surgery: A Systematic Review and Meta-Analysis.

Increased glycated hemoglobin (HbA1c) has been shown to increase the risk of mortality, myocardial infarction, and stroke after cardiac surgery, whereas its impact on the development of sternal wound infection (SWI) is less clear. A systematic review and meta-analysis were performed to evaluate the impact of preoperative HbA1c levels on the occurrence of SWI after adult cardiac surgery. Fourteen studies including 17,609 patients fulfilled the inclusion criteria and were included in this analysis. Diagnostic test meta-analysis of studies evaluating baseline HbA1c cut-off values ranging from 6% to 7% DCCT units (42-53 mmol/mol IFCC units) showed that the diagnostic odds ratio for deep SWI was 3.02 (95% confidence interval [CI] 2.10-4.35), while the diagnostic odds ratio for any SWI was 2.81 (95% CI 2.02-3.93). Binary meta-analysis confirmed that baseline HbA1c cut-off values ranging from 6% to 7% increased the risk for deep SWI (pooled incidence 2.7% vs 0.8%, risk ratio [RR] 3.01, 95% CI 2.32-3.90, I2 0%). Six studies included only diabetics and their pooled RR for deep SWI was 2.94 (1.59-5.45, I2 0%). Nine studies evaluated an HbA1c cut-off value of 7% and their RR for deep SWI was 3.22 (95% CI 2.38-4.37, I2 0%). The RR for any SWI was 2.92 (95% CI 2.42-3.53, I2 0%). This pooled analysis showed that the risk of SWI is substantially increased when preoperative HbA1c levels are over 6-7%. Future studies should evaluate whether postponing surgery for optimization of the glycemic control can reduce the risk of SWI in patients with increased levels of HbA1c.