Preliminary results of a meta-analysis evaluating the effect of immunonutrition on outcomes on outcomes of elective gastrointestinal surgery

Abstract

Providing tube feeds or liquid oral supplements containing additional arginine and/or omega-3 fatty acids and RNA – often referred to as 'immunonutrition' and more recently 'pharmaconutrition' – has been proposed as a strategy to decrease postoperative complications and duration of hospital length of stay for elective surgical patients. However outcomes of individual studies vary and the purported benefits remain controversial. A meta-analysis on this topic was recently published (Zheng et al., 2007), however further randomised controlled trials on this topic have appeared in the literature since this time. This meta-analysis has been undertaken to update the previously published meta-analysis and to attempt to elucidate the potential benefit of providing immune-enhanced nutrition in surgical patients. A search of electronic databases identified all RCTs comparing the use of pre and/or perioperative immunonutrition with standard nutrition provision in elective adult surgical patients between 1990 and 2008. The meta-analysis was prepared in accordance with the Quality of Reporting of Meta-analyses (QUOROM) statement. The variables analysed included mortality, total complications, infective complications, anastomotic leak (where applicable), and length of hospital stay. 20 distinct studies were identified that met inclusion criteria involving 1966 patients (immunonutrition n= 1048; standard nutrition n= 918). The provision of immunonutrition was shown to be associated with significant reductions in the incidence of total postoperative complications (OR 0.59, CI 0.41, 0.83, p=0.0023, Q=51.5, p=0.0001, I2 = 59%, CI 34.8%, 74.5%), postoperative infective complications (OR 0.49, CI 37, 64, p=0.0001, Q=25.2, p=0.1939 , I2 = 23%, CI 0%, 53.3%), anastomotic breakdown (OR 0.51, CI 0.31, 0.84 , p=0.0085, Q= 6.31, p=0.03 , I2 = 0%, CI 0%, 7.3%) when compared to standard nutritional provision. No effect of the differences in feed product formulation were seen with relation to mortality (OR 0.94, CI 0.49, 1.8, p=0.861, Q=4.49, p=0.99, I2 = 0%, CI 0%, 0%) or length of hospital stay (WMD -2.52, CI -3.71, -1.33, p=0.0001, Q= 219, p=0.0001, I2 = 90.2%, CI 87.5%, 93.4%). This meta-analysis lends strong support to the beneficial effects of immune-enhanced nutrition in the management of elective gastrointestinal surgical patients.