Effectiveness of amino acid supplementation in preventing acute kidney injury following cardiac surgery: A systematic review and meta-analysis of randomized controlled trials

Abstract

Introduction: Acute kidney injury (AKI) is a frequent complication of cardiac surgery, contributing to increased morbidity, longer hospital stays, and higher mortality. Evidence suggests amino acid (AA) supplementation may enhance renal blood flow and glomerular filtration rate (GFR), potentially reducing AKI risk; however, findings remain inconclusive. This study evaluated the efficacy of perioperative AA supplementation in preventing AKI and related complications post-cardiac surgery. Methods: PubMed, Embase, and Cochrane databases were searched for randomized controlled trials (RCTs) comparing AA supplementation versus standard care in preventing cardiac surgery-associated AKI. Main outcomes included AKI incidence (defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria), 30-day mortality, and renal replacement therapy (RRT) requirement. Pooled risk ratios (RRs) with 95% confidence intervals (CIs) were calculated using random-effects models. Statistical significance was set at p < 0.05. The certainty of the evidence (CoE) was assessed using the GRADE approach. Results: Six RCTs involving 4501 cardiac surgery patients were included. AA mixture interventions significantly reduced the risk of AKI stage 1 (RR: 0.56; 95% CI: 0.77–0.96; p =.009; CoE: Moderate) and Stage 3 (RR: 0.53; 95% CI: 0.34–0.83; p =.005; CoE: Moderate), but not stage 2 (RR: 1.24; 95% CI: 0.60–2.55; p =.568; CoE: Low). Preliminary findings from glutamic acid and glutamine (single AA interventions) showed potential benefits in reducing AKI incidence (CoE: Very low) and improving surrogate biomarkers, respectively. No significant effects were observed on mortality or RRT incidence for any intervention. Conclusion: AA mixtures likely reduce AKI incidence following cardiac surgery but show limited effects on mortality and RRT. Further trials are needed to confirm the benefits of glutamic acid and glutamine supplementation. Editorial Comment: Use of amino acid supplementation for the prevention of acute kidney injury after cardiac surgery may be effective, but more trial data and confidence in a beneficial effect is needed for this to be implemented in everyday clinical practice.