Early vs delayed enteral nutrition or parenteral nutrition in hospitalized patients: An umbrella review of systematic reviews and meta-analyses of randomized trials

We conducted an umbrella review to summarize the existing evidence on the effect of early enteral nutrition (EEN) compared with other approaches, including delayed enteral nutrition (DEN), parenteral nutrition (PN), and oral feeding (OF) on clinical outcomes in hospitalized patients. We performed a systematic search up to December 2021, in MEDLINE (via PubMed), Scopus, and Institute for Scientific Information Web of Science. We included systematic reviews with meta-analyses (SRMAs) of randomized trials investigating EEN compared with DEN, PN, or OF for any clinical outcomes in hospitalized patients. We used "A Measurement Tool to Assess Systematic Reviews" (AMSTAR2) and the Cochrane risk-of-bias tool for assessing the methodological quality of the systematic reviews and their included trial, respectively. The certainty of the evidence was rated using the "Grading of Recommendations Assessment, Development, and Evaluation" (GRADE) approach. We included 45 eligible SRMAs contributing with a total of 103 randomized controlled trials. The overall meta-analyses showed that patients who received EEN had statistically significant beneficial effects on most outcomes compared with any control (ie, DEN, PN, or OF), including mortality, sepsis, overall complications, infection complications, multiorgan failure, anastomotic leakage, length of hospital stay, time to flatus, and serum albumin levels. No statistically significant beneficial effects were found for risk of pneumonia, noninfectious complications, vomiting, wound infection, as well as number of days of ventilation, intensive care unit days, serum protein, and pre-serum albumin levels. Our results indicate that EEN may be preferred over DEN, PN, and OF because of the beneficial effects on many clinical outcomes.