Amino Acid Infusion for Kidney Protection in Nonkidney Surgery Patients: A Target Trial Emulation Study

Background: Acute kidney injury (AKI) is a common and severe postoperative complication with high mortality, yet effective preventive interventions are lacking. Recent studies suggested that amino acid (AA) infusion may improve renal outcomes in cardiac surgery patients. This study aims to investigate the effect of AA infusion on AKI prevention and kidney-related outcomes in patients who underwent nonrenal surgery. Methods: We emulated a sequential target trial including adult patients who underwent nonrenal surgery based on a large retrospective cohort from the China Renal Data System (CRDS) database. Treatment strategies involved the AA infusion or no AA infusion within 2 days post-surgery. The primary outcome was AKI within 7 days post-operation. Secondary outcomes included severe AKI, initiation of kidney replacement therapy (KRT), and incident chronic kidney disease (CKD). Adjusted cumulative incidences and risk differences between two treatment strategies were estimated using weighted pooled logistic regression models. Results: A total of 1,173,531 person-trials (705,137 unique patients) with nonrenal surgery were included. The weighted cumulative incidence of AKI within 7-day was 3.36% and 3.75% for those with and without AA infusion, resulting in a significant risk difference of -0.39% (CI, -0.48% to -0.29%) compare AA group to non-AA group. AA infusion was also associated with lower risks of severe AKI, use of KRT, and incident CKD, compared to non-AA group. Conclusion: AA infusion was associated with reduced risk of AKI, severe AKI, initiation of KRT, and incident CKD after nonrenal surgery, highlighting a promising preventive strategy for AKI.Table. Study outcomes and risk differences among the amino acid group and the control groupFigure 1. Cumulative incidences and risk differences of AKI among patients with amino acid infusion or not.