Enteral versus parenteral nutrition in critically ill patients: an updated systematic review and meta-analysis of randomized controlled trials

Abstract

BackgroundEnteral nutrition (EN) is recommended as the preferred route for early nutrition therapy in critically ill adults over parenteral nutrition (PN). A recent large randomized controlled trial (RCT) showed no outcome differences between the two routes. The objective of this systematic review was to evaluate the effect of the route of nutrition (EN versus PN) on clinical outcomes of critically ill patients.MethodsAn electronic search from 1980 to 2016 was performed identifying relevant RCTs. Individual trial data were abstracted and methodological quality of included trials scored independently by two reviewers. The primary outcome was overall mortality and secondary outcomes included infectious complications, length of stay (LOS) and mechanical ventilation. Subgroup analyses were performed to examine the treatment effect by dissimilar caloric intakes, year of publication and trial methodology. We performed a test of asymmetry to assess for the presence of publication bias.ResultsA total of 18 RCTs studying 3347 patients met inclusion criteria. Median methodological score was 7 (range, 2–12). No effect on overall mortality was found (1.04, 95 % CI 0.82, 1.33, P = 0.75, heterogeneity I2 = 11 %). EN compared to PN was associated with a significant reduction in infectious complications (RR 0.64, 95 % CI 0.48, 0.87, P = 0.004, I2 = 47 %). This was more pronounced in the subgroup of RCTs where the PN group received significantly more calories (RR 0.55, 95 % CI 0.37, 0.82, P = 0.003, I2 = 0 %), while no effect was seen in trials where EN and PN groups had a similar caloric intake (RR 0.94, 95 % CI 0.80, 1.10, P = 0.44, I2 = 0 %; test for subgroup differences, P = 0.003). Year of publication and methodological quality did not influence these findings; however, a publication bias may be present as the test of asymmetry was significant (P = 0.003). EN was associated with significant reduction in ICU LOS (weighted mean difference [WMD] -0.80, 95 % CI −1.23, −0.37, P = 0.0003, I2 = 0 %) while no significant differences in hospital LOS and mechanical ventilation were observed.ConclusionsIn critically ill patients, the use of EN as compared to PN has no effect on overall mortality but decreases infectious complications and ICU LOS. This may be explained by the benefit of reduced macronutrient intake rather than the enteral route itself.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-016-1298-1) contains supplementary material, which is available to authorized users.

Effectiveness of enteral feeding protocol on clinical outcomes in critically ill patients: a study protocol for before-and-after design

“…PN is associated with nosocomial infection and prolonged intensive care length of stay, but not mortality (2,3). The most-updated nutrition support guideline recommends that EN should be started within 24 to 48 hours after admission, while PN can be withheld for seven days depending on the risk of malnutrition (4).…”

Focus on nutrition

“…Indeed, after the publications of the CALORIES [5] study showing no harm related to PN in ICU patients, unfounded biases regarding the detrimental effect of early PN must be reconsidered together with the amount of calories administered [1]. Elke et al [6], in a review of the literature, compared PN to EN when the calories administered were similar and could not find any difference in terms of morbidity and mortality.…”

Editorial on “enteral versus parenteral early nutrition in ventilated adults with shock: a randomised, controlled, multicentre, open-label, parallel-group study (NUTRIREA-2)”

“…Many recent studies comparing EN with PN in the era of "optimal calorie" intake have shown that early nutrition support is beneficial regardless of the route (10,11). Studies from 1983-2014 showed that PN was associated with increased infection complication only when patients in the PN arm received more calorie than those in the EN arm, but when calories were provided for EN or PN in similar amounts, the difference in infectious complications was no longer observed (12). This has been nicely shown again in the NUTRIREA-2 trial where PN was found not to be harmful when given in optimized amounts.…”