CRD summary

The review assessed the effects of enteral nutrition with pharmaconutrient-enriched diets in critically ill patients. The authors concluded that enriched diets offer beneficial effects to patients requiring enteral feeding, although further research is required to identify the population who could benefit the most. The lack of individual study results, the inclusion of only published studies, and funding from the manufacturer of such diets may potentially bias the authors' conclusion.

Authors' objectives

To determine the effectiveness of enteral nutrition with pharmaconutrient-enriched diets in patients who were critically ill.

Searching

MEDLINE, EMBASE and the Cochrane CENTRAL Register were searched for articles published from 1966 to 2000. Additional studies were sought in the reference lists of retrieved articles and abstracts of proceedings of scientific meetings. Only published studies were included.

Study selection

Assessment of study quality

The authors assigned a quality score to each study (1 being the lowest and 5 the highest), using the Jadad instrument to assess randomisation, blinding and withdrawals. The authors did not state how the papers were assessed for quality, or how many reviewers performed the quality assessment.

Data extraction

Data were extracted from each included study in duplicate using a structured form and were checked independently for accuracy. For binary outcomes, data on the occurrence of each outcome of interest were extracted, while for continuous outcomes, data on the mean of each outcome of interest were extracted from individual studies using an intention-to-treat format.

Methods of synthesis

Results of the review

Twenty-six RCTs (n=2,473) were included in the review.

The authors stated that none of the included studies obtained a maximum quality score of 5 according to the Jadad scale.

Infectious complication rate: the authors stated that they were unable to find any significant effect on the rate of infectious complications, as most of the studies reported the incidence of infection at different locations instead of the overall ratio of infected individuals. No data were given in the report.

Wound infection: based on 15 RCTs, immunonutrition was associated with a significantly reduced likelihood of wound infection compared with the control (OR 0.46, 95% CI: 0.30, 0.69, P=0.003).

Intra-abdominal abscess: based on 6 RCTs, immunonutrition was associated with a significantly reduced likelihood of intra-abdominal abscess compared with the control (OR 0.26, 95% CI: 0.12, 0.58, P=0.0005).

Nosocomial pneumonia: based on 11 RCTs, immunonutrition was associated with a significantly reduced likelihood of nosocomial pneumonia compared with the control (OR 0.54, 95% CI: 0.35, 0.84, P=0.007).

Bacteraemia: based on 9 RCTs, immunonutrition was associated with a significantly reduced likelihood of bacteraemia compared with the control (OR 0.45, 95% CI: 0.29, 0.69, P=0.0002).

Urinary tract infections (UTIs): based on 10 RCTs, no statistically significant difference was shown between the immunonutrition and control groups on the occurrence of UTIs (OR 0.66, 95% CI: 0.43, 1.00, P=0.05).

Sepsis: based on 5 RCTs, no statistically significant difference was shown between the immunonutrition and control groups on the occurrence of sepsis (OR 0.45, 95% CI: 0.14, 1.45, P=0.18).

MODS and ARDS: no statistically significant difference was found between the immunonutrition and control groups on the incidence of MODS (1 RCT), while immunonutrition was associated with a significantly reduced likelihood of ARDS compared with the control (2 RCTs; OR 0.21, 95% CI: 0.09, 0.52, P=0.0007).

Mechanical ventilation duration: based on 7 RCTs, immunonutrition was associated with a significant reduction of 2.25 days (95% CI: -0.5, -3.9, P=0.009) of mechanical ventilation compared with the control.

Intensive care unit (ICU) and hospital length of stay: immunonutrition was associated with mean reductions of 1.6 days (95% CI: -1.2, -1.9, P<0.0001) and 3.4 days (95% CI: 2.7, 4.0, P<0.0001), respectively in ICU (8 RCTs) and hospital (12 RCTs) length of stay. There was evidence of statistical heterogeneity.

Mortality: based on 18 RCTs, no statistically significant difference was shown between the immunonutrition and control groups on in-hospital mortality (OR 1.1, 95% CI: 0.54, 1.42, P=0.5). A subgroup analysis according to patient population did not find a significant effect on mortality. There was no evidence of statistical heterogeneity for either the overall analysis or the subgroup analyses.

Cost information

The authors stated that three of the included studies calculated the added cost of the nutritional intervention to the hospital or ICU costs. Two studies found a reduction in the overall costs associated with enriched diets, while the other did not find any difference in cost.

Authors' conclusions

The authors stated that, given the evidence of beneficial effects and the absence of harmful effects associated with immunonutrition, its use could be recommended for patients in the ICU who require enteral feeding. However, further research is needed to identify the patient population who could benefit the most.

CRD commentary

The review addressed a clear research question and the inclusion criteria appeared appropriate. Several sources were searched for relevant published trials. The authors stated that publication bias was assessed but did not report the findings. In addition, it was unclear whether any language restrictions were applied to the search. Therefore, the possibility of publication and language could not be assessed. It was unclear whether the process used to select studies for inclusion was performed in duplicate, thus the possibility of selection bias could not be ruled out. However, methods were used to protect against reviewer bias and error in the data extraction process. The quality of the included studies was assessed systematically and discussed appropriately in the results.

Adequate details on the patient demographics, intervention and study design were given, which indicated clinical heterogeneity. There was no information on the results of each individual study. Furthermore, the authors stated that statistical tests of heterogeneity were performed, but the results were not reported for each outcome. This made it difficult to assess whether pooling the studies was appropriate. Consequently, the authors' conclusion and recommendation for future research appear appropriate.

Implications of the review for practice and research

Practice: The authors stated that there was fair evidence to recommend the use of enteral nutrition with modified diets in patients who are critically ill.

Research: The authors stated that well-conducted studies, designed according to established methodological and quality guidelines, are needed to determine the use of immunonutrition in specific sub-populations of critically ill patients.

Funding

Novartis Consumer Health.

Bibliographic details

Montejo J C, Zarazaga A, Lopez-Martinez J, Urrutia G, Roque M, Blesa A L, Celaya S, Jero R C, Galban C, De Lorenzo A G, Grau T, Mesejo A, Ortiz-Leyba C, Planas M, Ordonez J, Jimenez F J. Immunonutrition in the intensive care unit: a systematic review and consensus statement. Clinical Nutrition 2003; 22(3): 221-233. [PubMed: 12765660]

Indexing Status

Subject indexing assigned by NLM

MeSH

Critical Care /methods; Critical Illness /therapy; Enteral Nutrition; Hospital Mortality; Humans; Immune System /physiology; Intensive Care Units; Nutritional Physiological Phenomena; Outcome Assessment (Health Care); Randomized Controlled Trials as Topic

AccessionNumber

12003001363

Database entry date

31/07/2005

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.