No previous research has specifically investigated the relationship between postoperative glycemic variability (GV) and acute kidney disease (AKD) in patients undergoing cardiac surgery. In this study, several methods of modelling postoperative GV were used to examine the association between GV and AKD risk and subtypes of AKD.

We undertook a retrospective study involving a total of 8,090 adult patients from three academic medical centers in Eastern China who underwent cardiac surgery with cardiopulmonary bypass between 2015 and 2023. Seven-day postoperative GV was calculated using the standard deviation (SD), coefficient of variation (CV), mean amplitude of glycemic excursion (MAGE), average daily risk range (ADRR), and time out of target range (TOR). The primary focus was on the occurrence of AKD between 8 and 90 days post-surgery, which was further categorized into persistent AKD and delayed AKD depending on the acute kidney injury (AKI) status in the first 7 days.

During the 8-90 days postoperative period, AKD occurred in 522 out of 8,090 patients (6.5%). Seven-day postoperative GV was significantly and consistently higher in the AKD group (p<0.001 for each metric). After adjusting for relevant covariates, 7-day GV metrics were significantly associated with elevated AKD risk (standardized hazard ratio (SHR):1.20 (95% confidence interval (CI): (1.12 – 1.27) for SD; SHR: 1.30 (95% CI: 1.20 – 1.40) for TOR). GV was correlated with persistent AKD, while no statistically significant association was observed between GV and delayed AKD. Unique cutoff thresholds were calculated for each GV metric to provide a quantitative indicator of high GV, enhancing its practical utility.

Our study highlights the association between postoperative GV and increased AKD risk, and identifies specific GV thresholds in adults undergoing cardiac surgery.