CI: Enteral Nutrition vs. Parenteral Nutrition (2012)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
The purpose was to apply data from eight prospective randomized clinical trials to identify whether early enteral nutrition (TEN) had fewer septic complications than TPN.
Inclusion Criteria:
  1. Nutrition support initiation within 72 hours postoperative. 
  2. Studies that used vivonex TEN or one of 3 study TPN solutions as initial postoperative feeding.  Participants were moderately to severely stressed.  All studies had daily documentation of complications.
Exclusion Criteria:
  1. Preexisting diseases, including advanced diabetes, chronic renal failure, cirrhosis, and inflammatory bowel disease.
  2. Conditions precluding use of enteral nutrition.
  3. Severe head injury
  4. Condition precluding aggressive nutritional support
  5. Hospitalization of > 10 days before study enrollment
  6. Prior surgical procedures during hospitalization
  7. Preoperative nutritional support
  8. Nonstudy nutritional solution used immediately after operation
Description of Study Protocol:

Phase I meta analysis – complication data were extracted from study patient case report forms

Homogeneity was assessed by two-way ANOVA tests. Logistic regression using PROC CATMOD was used to analyze categorical modeling of data.  Stratified contingency tables were also used.

Phase II meta analysis – intent to treat analysis conducted to evaluate morbidity and mortality data. Individual patient data were used to permit comparisons of five patient subgroups: all patients, all trauma patients, penetrating trauma patients, blunt trauma patients, and all nontrauma patients. 

Statistical tools used: two-way ANOVA test, F-test, and the Cochran-Mantel-Haenzel test to determine whether significant associations existed between treatment group and presence of categorical responses.

All participants received nutrition support in 8 to 72 hours after operation

Data Collection Summary:

Evaluated variables in Phase I:

  1. diet intake and nutritional responses (nitrogen balance)
  2. change in body weight
  3. time nutritional support started
  4. biochemical responses
  5. GI tolerance
  6. postoperative complications
  7. length of time in hospital, ICU, and cost of hospitalization.

Evaluated variables in Phase II

  1. Length of stay in hospital, and ICU
  2. 10 day complication rates and types of complications
10- and 30-day mortality rates.
Description of Actual Data Sample:

230 patients (118 received enteral nutrition and 112 received TPN)

81 received TEN by jejunostomy, 36 by nasoenteric, and 1 by gastrojejunal tube.

Summary of Results:

Phase I – assessed 194 (92 TEN, 102 TPN) patients, including treatment failures and excluding dropouts. 

  • Time to start nutritional support did not significantly differ between groups.
  • Baseline, midstudy, and end-of study nitrogen intake and nitrogen balance were significantly less in the TEN group
  • Weight gain by end of study was significantly less in TEN group (difference 1.6 kg; p=0.03)
  • No significant differences in biochemical data with the exception of lower glucose levels in TEN. (19mg/dL at baseline, p=0.02; 28 mg/dL at midstudy, p=0.03; and 94 mg/dL at end of study, p=0.0001)
  • End of study nutritional markers (total protein, albumin, and transferring) were slightly higher in TEN group (p= not significant)
  • GI intolerance significantly greater in TEN
  • Significantly fewer TEN patients had total complications (TEN, 38%; TPN, 59%; p=0.007) and septic complications (TEN, 17%; TPN, 44%; p=0.0001)

Phase II- assessed all 230 patients.

  • Twice as many TPN as TEN patients developed one or more infections (TEN, 16%; TPN, 35%; p=0.01).
  • Small subset for analysis of LOS.  No significant differences were seen between treatment groups when 10-day and 30-day mortality rates, length of stay, and cost were compared.
  • Patients in the penetrating trauma group experienced significantly different lengths of stay (TEN, 17; TPN, 22; p=0.05)
  • Total hospital cost data wasn’t available from all sites and could not be compared.
Author Conclusion:

Primary strength of this meta-analysis was homogeneity across and within studies.

The authors concluded that available research implicates the gut as the source of bacteria found in late nosocomial infections and it may be possible to reduce infectious complications with early enteral feedings in high-risk surgical patients.

All trauma and blunt trauma patients fed TEN experienced the most significant reduction in septic complications and the penetrating trauma group demonstrated a trend toward reduced septic rates.

Early postoperative enteral feeding is possible in high-risk surgical patients.

Funding Source:
Norwich Eaton Pharmaceuticals, Inc.
Pharmaceutical/Dietary Supplement Company:
University/Hospital: Denver General Hospital, Ben Taub Hospital, University of Texas, Houston, Montreal General Hospital (Canada) Buffalo General Hospital, Medical College of Virginia, Good Samaritan Hospital
Reviewer Comments:
PRCTs not blinded, several unpublished studies in meta analysis review
Quality Criteria Checklist: Review Articles
Relevance Questions
  1. Will the answer if true, have a direct bearing on the health of patients? Yes
  2. Is the outcome or topic something that patients/clients/population groups would care about? Yes
  3. Is the problem addressed in the review one that is relevant to dietetics practice? Yes
  4. Will the information, if true, require a change in practice? Yes
Validity Questions
  1. Was the question for the review clearly focused and appropriate? Yes
  2. Was the search strategy used to locate relevant studies comprehensive? Were the databases searched and the search termsused described? Yes
  3. Were explicit methods used to select studies to include in the review? Were inclusion/exclusion criteria specified andappropriate? Wereselectionmethods unbiased? Yes
  4. Was there an appraisal of the quality and validity of studies included in the review? Were appraisal methodsspecified,appropriate, andreproducible? Yes
  5. Were specific treatments/interventions/exposures described? Were treatments similar enough to be combined? No
  6. Was the outcome of interest clearly indicated? Were other potential harms and benefits considered? No
  7. Were processes for data abstraction, synthesis, and analysis described? Were they applied consistently acrossstudies and groups? Was thereappropriate use of qualitative and/or quantitative synthesis? Was variation in findings among studies analyzed? Were heterogeneity issued considered? If data from studies were aggregated for meta-analysis, was the procedure described? Yes
  8. Are the results clearly presented in narrative and/or quantitative terms? If summary statistics are used, are levels ofsignificance and/or confidence intervals included? Yes
  9. Are conclusions supported by results with biases and limitations taken into consideration? Are limitations ofthe review identified anddiscussed? No
  10. Was bias due to the review's funding or sponsorship unlikely? Yes