Meta-analysis of immunonutrition in major abdominal surgery

Area of Science:

• Surgical Nutrition
• Clinical Trials
• Evidence-Based Medicine

Background:

• Major abdominal surgery poses significant risks, including complications and prolonged hospital stays.
• Immunonutrition, a specialized nutritional support, is explored for its potential to mitigate these risks.
• The influence of study bias on reported outcomes requires careful evaluation.

Purpose of the Study:

• To assess the benefits of immunonutrition in patients undergoing major abdominal surgery.
• To investigate the impact of study subgroups and bias on immunonutrition efficacy.
• To synthesize evidence from randomized controlled trials (RCTs).

Main Methods:

• Systematic literature search of MEDLINE, Embase, and CENTRAL (1985-2015).
• Inclusion of RCTs on immunonutrition in major abdominal surgery.
• Evaluation of mortality, overall complications, infectious complications, and hospital stay, with bias assessment using GRADE criteria.

Main Results:

• Immunonutrition did not alter mortality but initially showed reductions in overall complications, infectious complications, and hospital stay.
• These positive effects disappeared when trials with high or unclear risk of bias were excluded.
• Publication bias was noted for infectious complications; non-industry-funded trials showed no benefits, unlike industry-funded trials.

Conclusions:

• Immunonutrition's effect on mortality is high-quality evidence, showing no alteration.
• Evidence for reduced complications and hospital stay is low to moderate quality, with confidence diminished by bias.
• The presence of bias, particularly industry funding, significantly impacts the perceived benefits of immunonutrition.