Early Versus Late Enteral Nutrition in Critically Ill Patients: Meta-Analysis of Randomized Controlled Trials

Background: Nutritional support is a cornerstone in the management of critically ill patients, with early enteral nutrition (EEN) advocated by major guidelines. However, the impact of EEN compared to delayed enteral nutrition (DEN) on clinical outcomes remains debated. Objective: This meta-analysis evaluates the effect of EEN within 48 hours of intensive care unit (ICU) admission or post-surgery on morbidity and mortality in critically ill patients. Methods: A systematic search was conducted across PubMed, Embase, BioMed, and the Cochrane Central Register of Controlled Trials. Eighteen randomized controlled trials (RCTs) involving 2,146 critically ill patients were included. The primary outcomes were mortality, infectious complications, and organ dysfunction. Secondary outcomes included ICU length of stay (LOS), mechanical ventilation (MV) duration, ventilator-free days, and antibiotic use. Meta-analysis was performed using a random-effects model. Results: EEN significantly reduced the risk of infectious complications (RR = 0.65, 95% CI: 0.50–1.76, P = 0.32), ICU LOS (MD = 0.48 days, 95% CI: -0.78–1.18, P = 0.002), and MV duration (MD = 1.25 days, 95% CI: 0.47–2.02, P = 0.002). Additionally, EEN decreased SOFA scores (MD = 0.48, 95% CI: -0.78–1.18, P = 0.0001) and APACHE II scores (MD = 1.71, 95% CI: 0.97–2.44, P = 0.00001). However, no significant difference was found in mortality (RR = 0.86, 95% CI: 0.70–1.05, P = 0.14) or pneumonia (RR = 0.89, 95% CI: 0.71–1.12, P = 0.32). Conclusion: EEN within 48 hours significantly improves clinical outcomes, reducing infectious complications, ICU LOS, MV duration, and severity scores without impacting mortality or pneumonia incidence. Early initiation of enteral nutrition should be prioritized in critically ill patients.