Meta Analysis
Early enteral nutrition in acutely ill patients:A systematic review
This review may be edited
Posted By: Pip Heighes
Posted Date: 24/11/08
Title: Early enteral nutrition in acutely ill patients:A systematic review
Authors: Marik, PE & Zaloga, GP
Reference: Crit Care Med 2001 Dec; 29(12):2387-8.
Link: Click here for a direct link to the paper. A password may be required for access to fulltext.
Abstract: OBJECTIVE: To evaluate the effect of early enteral nutrition on the outcome of critically ill and injured patients. DATA SOURCES: MEDLINE, citation review of relevant primary and review articles, personal files, and contact with expert informants. STUDY SELECTION: Randomized, controlled studies that compared early with delayed enteral nutrition in hospitalized adult postoperative, trauma, head-injured, burn, or medical intensive care unit (ICU) patients. From 161 articles screened, 27 were identified as randomized, controlled trials comparing early with delayed enteral nutrition and were included for data extraction. Of these, 12 were excluded. None of the studies included medical ICU patients. DATA EXTRACTION: Fifteen studies containing 753 subjects were analyzed. Descriptive and outcome data were extracted independently from the articles by the two reviewers. Main outcome measures were infections, noninfectious complications, length of hospital stay, and mortality. The meta-analysis was performed using the random effects model. DATA SYNTHESIS: Early enteral nutrition was associated with a significantly lower incidence of infections (relative risk reduction, 0.45; 95% confidence interval, 0.30-0.66; p =.00006; test for heterogeneity, p =.049) and a reduced length of hospital stay (mean reduction of 2.2 days; 95% confidence interval, 0.81-3.63 days; p =.004; test for heterogeneity, p =.0012). There were no significant differences in mortality or noninfectious complications between the two groups of patients. CONCLUSIONS: The results of this meta-analysis support the experimental data demonstrating the benefit of the early initiation of enteral nutrition. The results of this meta-analysis must, however, be interpreted with some caution because of the significant heterogeneity between studies.
Are the Results Valid?
1. Did the overview address a focused clinical question?
The authors were interested in an acutely ill population, defined as hospitalised adult postoperative trauma, head-injured, burn, or medical ICU patients who were given a specific intervention, specified as early versus late/delayed instituion of enteral nutrition with reporting of at least one of the predefined outcomes of interest
2. Were the criteria used to select articles for inclusion appropriate?
The authors stated they would only include RCT's in the predefined patient population evaluating early enteral nutrition. This was defined as the initiation of enteral feeds within 36 horus of admission to the hospital or within 36 hours of surgery. Delayed was defined as nutritional support that was commenced after 36 hours (admission or surgery).
3. Is it unlikely that important, relevant studies were missed?
The authors conducted a search of Medline using suitable broad sensitive MESH terms for nutrition. They do not report searching EMBASE or any other relevant bibliographic databases.
They contacted experts, reviewed personal files, hand searched bibliographies and reference lists.
4. Was the validity of the included studies appraised?
The authors state that this systematic review is "stronger than previous overviews on this topic in its adherence to strict methodologic criteria......we assessed the validity of eligible studies." There is however no reporting of this assessment of validity in the paper.
5. Were assessments of studies reproducible?
The authors report repeating the search stratgey iteratively until no new potential RCT's were found. They report individually searching personal files and contacting experts however it is unclear if all the search was done individually or only this component of the search.
6. Were the results similar from study to study?
The tests for heterogeneity were significant for infectious complications chi-square=19.73; p=0.049 , non-infectious complications chi-square=15.69; p=0.047 and length of stay chi-square=30.73; p=0.0012
Patient populations of the RCT's included in this MA were quite varied and included abdmoninal surgery, head injury, trauma and burns.
What are the Results?
1. What are the overall results of the overview?
Early EN led to a statistically significant reduction in infectious complications
RR 0.45 (95% CI 0.3 0.66) P=0.00006
, chi-square of heterogeneity = 19.73; p=0.049 ,
There was also a statistically significant reduction in length of stay
WMD - 2.2 days (95% CI -0.81 to -3.63) p = 0.002
, chi-square of heterogeneity = 30.73; p=0.0012
2. How precise were the results?
See CI above
Will the Results Help Me In Caring For My Patients?
1. Can the results be applied to my patient care
These results need to be interpreted with caution due to significant heterogeneity.
The results from the abdominal surgery group play a strong influence on the overall results. These patients are not critically ill, they are elective surgical patients.
It is therefore difficult to use this MA to guide practice in ICU.
Regardless of what analytic technique is used (random vs fixed effects), significant heterogeneity may indicate that clinically different patient groups should not be pooled.
2. Were all clinically important outcomes considered?
Most, however costs, physical function and quality of life were not considered.
3. Are the benefits worth the harms and costs?
Unable to determine from the results of this MA

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Early enteral nutrition in acutely ill patients:A systematic review

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