Objectives: To identify, appraise, and synthesize the most current evidence to determine whether early enteral nutrition alters patient outcomes from critical illness.
Data sources: Medline and Embase were searched. The close out date was November 20, 2017.
Study selection: Early enteral nutrition was defined as a standard formula commenced within 24 hours of ICU admission. Comparators included any form of nutrition support "except" early enteral nutrition. Only randomized controlled trials conducted in adult patients requiring treatment in an ICU were eligible for inclusion.
Data extraction: The primary outcome was mortality. Secondary outcomes included pneumonia, duration of mechanical ventilation, and ICU and hospital stay.
Data synthesis: Six-hundred ninety-nine full-text articles were retrieved and screened. Sixteen randomized controlled trials enrolling 3,225 critically ill participants were included. Compared with all other types of nutrition support, commencing enteral nutrition within 24 hours of ICU admission did not result in a reduction in mortality (odds ratio, 1.01; 95% CI, 0.86-1.18; p = 0.91; I = 32%). However, there was a differential treatment effect between a priori identified subgroups (p = 0.032): early enteral nutrition reduced mortality compared with delayed enteral intake (odds ratio, 0.45; 95% CI, 0.21-0.95; p = 0.038; I = 0%), whereas a mortality difference was not detected between early enteral nutrition and parenteral nutrition (odds ratio, 1.04; 95% CI, 0.89-1.22; p = 0.58; I = 30%). Overall, patients who were randomized to receive early enteral nutrition were less likely to develop pneumonia (odds ratio, 0.75; 95% CI, 0.60-0.94; p = 0.012; I = 48%).
Conclusions: Overall, there was no difference between early enteral nutrition and all other forms of nutrition support. A priori planned subgroup analysis revealed early enteral nutrition reduced mortality and pneumonia compared with delayed enteral intake; however, there were no clear clinical advantages of early enteral nutrition over parenteral nutrition.