Intensive Care Medicine

, Volume 31, Issue 1, pp 12–23 | Cite as

Parenteral vs. enteral nutrition in the critically ill patient: a meta-analysis of trials using the intention to treat principle

  • Fiona Simpson
  • Gordon Stuart Doig
Systematic Review



Controversy surrounds the use of parenteral nutrition in critical illness. Previous overviews used composite scales to identify high-quality trials, which may mask important differences in true methodological quality. Using a component-based approach this meta-analysis investigated the effect of trial quality on overall conclusions reached when standard enteral nutrition is compared to standard parenteral nutrition in critically ill patients.


An extensive literature search was undertaken to identify all eligible trials. We retrieved 465 publications, and 11 qualified for inclusion. Nine trials presented complete follow-up, allowing the conduct of an intention to treat analysis.


Aggregation revealed a mortality benefit in favour of parenteral nutrition, with no heterogeneity. A priori specified subgroup analysis demonstrated the presence of a potentially important treatment-subgroup interaction between studies of parenteral vs. early enteral nutrition compared to parenteral vs. late enteral. Six trials with complete follow-up reported infectious complications. Infectious complications were increased with parenteral use. The I 2 measure of heterogeneity was 37.7%.


Intention to treat trials demonstrated reduced mortality associated with parenteral nutrition use. A priori subgroup analysis attributed this reduction to trials comparing parenteral to delayed enteral nutrition. Despite an association with increased infectious complications, a grade B+ evidence-based recommendation (level II trials, no heterogeneity) can be generated for parenteral nutrition use in patients in whom enteral nutrition cannot be initiated within 24 h of ICU admission or injury.


Enteral nutrition Parenteral nutrition Meta-analysis Randomised controlled trials Critical illness Critical appraisal 



This work was supported in part by grants from the Australian and New Zealand Intensive Care Foundation and the NorthCare Foundation.


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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  1. 1.Department of NutritionRoyal North Shore HospitalSydneyAustralia
  2. 2.Intensive Care, Northern Clinical SchoolUniversity of SydneySydneyAustralia
  3. 3.Intensive Therapy UnitRoyal North Shore HospitalSt. LeonardsAustralia

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