Preoperative serum creatinine changes and acute kidney injury in patients underwent cardiac surgery

Introduction: Preoperative serum creatinine fluctuations are common in open-heart surgery, and their association with postoperative acute kidney injury (AKI) and the combined impact on patient outcomes warrant further investigation. Methods: This retrospective cohort study assessed patients undergoing open-heart surgery. Preoperative serum creatinine changes (ΔScr) were calculated as the difference between the serum creatinine value within 48 h before surgery and baseline. Patients were categorized into three groups based on ΔScr: negative (< 0 mg/dl), normal (0-0.3 mg/dl), and elevated (≥0.3 mg/dl). Multivariable logistic regression and restricted cubic spline models were used to analyze the clinical outcomes. Results: Of the 560 patients included, 40.2% developed AKI. There were significant increases in the odds of AKI [adjusted odds ratio (AOR), 1.51; 95% CI, 1.32-1.72, per 0.1 mg/dl increase], severe AKI (AOR, 1.45; 95% CI, 1.24-1.70), and AKI non-recovery (AOR, 1.37; 95% CI, 1.19-1.59). In AKI patients, negative ΔScr was associated with a higher rate of in-hospital mortality and ICU LOS >72 h compared to without AKI, while elevated ΔScr showed no significant differences. In addition, negative ΔScr was associated with a higher risk of in-hospital mortality (AOR, 4.50; 95% CI, 1.00-20.15) and ICU LOS >72 hours (AOR, 2.81; 95% CI, 1.13-6.96) compared with normal ΔScr. No significant associations were observed with elevated ΔScr. In contrast, among patients without AKI, neither negative nor elevated ΔScr were associated with in-hospital mortality or prolonged ICU LOS. Conclusions: In this retrospective study of elective cardiac surgery, negative changes in preoperative serum creatinine were less likely to development of AKI. However, patients with negative changes who developed postoperative AKI had a higher risk of in-hospital mortality and prolonged ICU stays. No significant associations with these outcomes were observed with elevated changes.