Protective effect of intravenous amino acid on kidney function: A systematic review and meta-analysis of randomized controlled trials

Background: Acute kidney injury (AKI) is a common complication in critically ill and cardiac surgery patients. Intravenous amino acids can increase renal perfusion and replenish renal functional reserves. However, the exact therapeutic efficacy of intravenous amino acids in reducing the incidence of AKI remains uncertain. Therefore, this study aims to comprehensively review the existing evidence to assess the potential of intravenous amino acids in kidney protection. Methods: EMBASE, PubMed, MEDLINE, and the Cochrane Library were searched for randomized controlled trials published on or before July 2, 2024, that examined the relationship between Intravenous amino acids and renal function. We extracted population characteristics and outcome variables related to renal function from randomized controlled trials comparing intravenous amino acid supplementation with no supplementation. We assessed this evidence using the Risk of Bias 2 (RoB2) tool for randomized controlled trials. Data were synthesized using a random-effects model. Results: This review included 7 randomized controlled trials with a total of 505 patients. The results showed that compared with the control group, intravenous amino acid administration significantly reduced the incidence of AKI (RR: 0.81, 95 % CI: 0.68-0.97, P = 0.02) and increased urine output (MD: 308.87, 95 % CI: 168.68-449.06, P < 0.0001). However, intravenous amino acids did not reduce mortality or the incidence of kidney replacement therapy, with no statistical difference in 30-day mortality (RR: 0.93, 95 % CI: 0.65-1.34, P = 0.71), 90-day mortality (RR:1.00, 95 % CI: 0.77-1.29, P = 0.98), or need for kidney replacement therapy (RR: 0.92, 95 % CI: 0.41-2.06, P = 0.83). Subgroup analysis suggested that, regardless of sample size, intravenous amino acid administration reduced the incidence of AKI and was particularly significant in patients undergoing cardiac and major vascular surgery. Furthermore, intraoperative intravenous amino acid therapy demonstrated a significant reduction in the incidence of AKI compared to postoperative administration. Conclusions: Intravenous amino acids protect renal function in patients at high risk of AKI, particularly after cardiac surgery. It reduces the incidence of AKI and increases urine output, but has no significant effect on KRT and mortality.