Preoperative Standard Oral Nutrition Supplements vs Immunonutrition: Results of a Systematic Review and Meta-Analysis

Abstract

Multiple studies and meta-analyses have suggested some benefit to immunonutrition (IN) supplements. These studies have often included preand post-operative regimens and have utilized inconsistent controls ranging from standard non-supplemented oral diets to high-quality isonitrogenous controls. This study aims to compare outcomes after preoperative nutritional supplementation with IN vs. standard oral nutritional supplements (ONS) or a regular diet without supplements. We performed a systematic literature review. 8 randomized controlled trials (RCTs) of preoperative IN vs. ONS were identified and 9 RCTs of IN vs. no supplements were also identified. Meta-analysis was performed for reported outcomes including wound infection, infectious and non-infectious complications, and length of stay (LOS). The meta-analysis was prepared in accordance with Preferred Reporting of Systematic Reviews and Meta-Analyses (PRISMA) recommendations. We identified 561 patients in 8 RCTs of preoperative IN vs. ONS. 895 patients were identified in 9 RCTs of IN vs. no supplements. When compared to ONS, preoperative IN was not associated with reduced wound infection (OR 0.97, 95% Confidence Interval (CI) 0.45 to 2.11), all infectious complications (OR 0.71, 95% CI 0.30 to 1.68), non-infectious complications (OR 1.25, 95% CI 0.64 to 2.43), or LOS (mean difference 0.07 days, 95% CI 2.29 to 2.43). In RCTs controlled with non-supplemented standard diets, preoperative IN was associated with decreased infectious complications (OR