Abstract
BACKGROUND: Perioperative glucose fluctuations are a common complication of cardiac surgery, and acute kidney injury (AKI) is a serious complication after cardiac surgery. Body Mass Index (BMI) is associated with postoperative AKI, and BMI increases. There is often an increase in the baseline level of blood sugar, and BMI larger patients have more significant postoperative glucose fluctuations. The intrinsic relationship between BMI, postoperative glucose fluctuations, and AKI remains unclear. This study aimed to explore whether postoperative glucose fluctuations mediate the relationship between BMI and AKI. METHODS: This study enrolled patients who underwent elective cardiac surgery at the Affiliated Hospital of Xuzhou Medical University from 2018 to 2023. Generalized linear and logistic regression models were employed to examine the associations among these three variables, while mediation effect analysis was utilized for discussion. RESULTS: A total of 859 patients were included in this study. The incidence of postoperative AKI was found to be 32.2%. BMI and perioperative hyperglycemic fluctuations were independent risk factors for postoperative AKI. When control variables were added, the mediating effect was still significant, with the direct effect being 0.063 (95% CI: 0.009-0.110), the indirect effect being 0.057 (95% CI: 0.033-0.080), the total effect being 0.120 (95% CI: 0.070-0.180), and the proportion of the mediating effect being 47.5% (95% CI: 29.3-86.0%). CONCLUSION: Perioperative glucose fluctuations partially mediate BMI's effect on postoperative AKI. For patients with an elevated BMI, stringent control of perioperative blood glucose fluctuations may be beneficial in mitigating the risk of postoperative AKI.