Effect of early parenteral nutrition versus enteral nutrition alone on all-cause mortality in critically ill adults: A systematic review and meta-analysis.

Background

While early enteral nutrition (EN) is standard for critically ill patients with functional gastrointestinal tracts, parenteral nutrition (PN) is needed when EN is contraindicated or insufficient. Optimal PN timing/selection remains controversial. This meta-analysis evaluated the impact of early PN on mortality and clinical outcomes in critically ill adults.

Methods

We searched PubMed, Web of Science, Embase, and the Cochrane Library for randomized controlled trials (RCTs) published from January 2000 up to January 2025 comparing PN (total or supplemental) with EN alone in critically ill adults. The primary outcome was all-cause mortality. Risk of bias was evaluated via the Cochrane Risk of Bias 2.0 tool, and evidence quality was graded using the grading of recommendations assessment, development and evaluation (GRADE) framework. The study was registered in international prospective register of systematic reviews (PROSPERO) (CRD42023462386).

Results

Twenty RCTs enrolling 12,865 patients were included. Early PN yielded comparable 30-day (risk ratio [RR] 0.96, 95% confidence interval [CI] 0.90-1.03, P = 0.29) and 90-day all-cause mortality (RR 0.95, 95% CI 0.86-1.04, P = 0.26) relative to EN alone. However, PN was associated with lower ICU mortality (RR 0.92, 95% CI 0.86-0.99, P = 0.03), shorter mechanical ventilation duration, and reduced gastrointestinal intolerance. Conversely, PN increased the risk of overall infections (RR 1.12, P = 0.002) and bloodstream infections (RR 1.27, P = 0.005).

Conclusion

In critically ill adults, early PN was associated with reduced ICU mortality and mechanical ventilation duration, as well as lower gastrointestinal intolerance, but it was also associated with an increased risk of infections, notably bloodstream infections. Individualized PN strategy with rigorous infection control is warranted when EN alone is insufficient.