No bene fi t of higher protein dosing in critically ill patients: a systematic review and meta-analysis of randomized controlled trials

Purpose: The optimal range of protein dosage and effect of high-dose protein on critically ill patients remain controversial. We conducted a meta-analysis to compare higher and lower doses of protein supplementation for nutritional support in critically ill patients.<br /> Methods: We searched the PubMed, Embase, Scopus, and Cochrane Library databases for randomized controlled trials that compared higher ( >= 1.2 g/kg per day) versus lower (<1.2 g/kg per day) doses of protein supplementation among critically ill adult patients. This search spanned from the inception of relevant databases to November 20, 2023. Our primary endpoint of interest was overall mortality, while secondary endpoints included length of stay in the intensive care unit, length of hospital stay, duration of mechanical ventilation, and incidence of acute kidney injury. Results: Seventeen studies including 2,965 critically ill patients were included in our meta-analysis. The pooled analyses showed no signi fi cant difference in overall mortality (RR 1.03, 95%CI [0.92 - 1.15], P = 0.65, I-2 = 0%), length of intensive care unit stay (MD 0.19, 95%CI [ - 0.67 to 1.04], P = 0.66, I-2 = 25%), length of hospital stay (MD 0.73, 95%CI [ - 1.59 to 3.04], P = 0.54, I-2 = 27%), duration of mechanical ventilation (MD - 0.14, 95%CI [ - 0.83 to 0.54], P = 0.68, I-2 = 8%), and incidence of acute kidney injury (RR 1.11, 95%CI [0.87 - 1.41], P = 0.38, I-2 = 0%) between critically ill patients receiving higher or lower doses of protein supplementation. Conclusions: For critically ill patients, the protein supplementation dose had no signi fi cant effect on clinical outcomes, including overall mortality, length of intensive care unit and hospital stay, duration of mechanical ventilation, and incidence of acute kidney injury.