Protein intake and clinical outcomes in critically ill patients: A dose-response and pairwise meta-analysis of randomized controlled trials.

BACKGROUND

The optimal protein intake for critically ill patients remains uncertain. This systematic review and dose-response meta-analysis aimed to evaluate the effect of high-protein nutritional support on clinical outcomes in intensive care unit (ICU) patients.

METHODS

Randomized controlled trials (RCTs) comparing high- versus low-protein nutrition in critically ill adults with similar energy intake were identified through PubMed, Web of Science, and Scopus (up to June 2023). A random-effects model was used to pool risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals (CIs). Linear and non-linear trends were assessed using the one-stage cubic spline regression model.

RESULTS

Twenty-three RCTs were included. The summary RR was 0.83 (95% CI: 0.64-1.08; I2=63.6%; n=17) for mortality and 1.05 (95% CI: 0.88-1.25; I2=0%; n=7) for infections. The summary MD was -0.23% (-0.76 to 0.29, I2=5.6%, n=14) for mechanical ventilation days, -0.40 (-1.11 to 0.32, I2=0%, n=17) for ICU days, 0.73 (-1.11 to 2.58, I2=6%, n=10) for hospital days, and -3.44 (-4.99 to -1.90; I2=16.4%; n=5) for muscle atrophy. There was no evidence of linear or nonlinear trends.

CONCLUSION

Although higher protein intake had no significant effect on mortality or length of stay, it was associated with reduced muscle wasting. This suggests a potential role in preserving lean mass and supporting long-term functional recovery.

SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42024480303.