Effects of arginine‐enriched enteral nutrition on clinical outcomes with infectious events and muscle volume in critically ill patients: A systematic review and meta‐analysis

BACKGROUND: Arginine is a conditionally essential amino acid that is deficient in catabolic states. However, the effects and safety of arginine-enriched enteral nutrition (EN) supplements in critically ill patients remain unclear. Therefore, the present systematic review and meta-analysis of randomized controlled trials (RCTs) investigated this issue. METHODS: We conducted a systematic review and meta-analysis. We searched the PubMed, CENTRAL, and ICHUSHI databases from inception to October 3, 2024. RCTs comparing arginine-enriched EN supplements with placebo or standard composition nutrition supplements for critically ill patients were examined. The primary outcome was the incidence of infection. Secondary outcomes were mortality, length of intensive care unit stay, duration of mechanical ventilation, muscle volume, physical function, and adverse events. Risk of bias was assessed using Cochrane Risk of Bias 2. The certainty of evidence (CoE) was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation approach. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated. RESULTS: Twenty-three studies (n = 2311) that met the selection criteria were included in the meta-analysis. Arginine-enriched EN did not reduce the incidence of infection (RR, 0.98; 95% CI, 0.63-1.54; P = 0.93) or other outcomes. Only one study examined muscle volume. No RCTs evaluated physical function. CoE was mostly low, and heterogeneity was high. CONCLUSION: Arginine-enriched EN may not exert beneficial effects on the incidence of infection or other outcomes. However, because no studies have examined the administration of arginine alone and few RCTs investigated physical outcomes, such as muscle volume and physical function, further research is warranted.