Enteral nutrition formulations for acute pancreatitis

Acute pancreatitis is a common and potentially lethal disease with increasing incidence. Severe cases are characterised by high mortality, and despite improvements in intensive care management, no specific treatment relevantly improves clinical outcomes of the disease. Meta-analyses suggest that enteral nutrition is more effective than conventional treatment consisting of discontinuation of oral intake with use of total parenteral nutrition. However, no systematic review has compared different enteral nutrition formulations for the treatment of patients with acute pancreatitis.

To assess the beneficial and harmful effects of different enteral nutrition formulations in patients with acute pancreatitis.

We searched the Cochrane Upper Gastrointestinal and Pancreatic Diseases Group Specialised Register of Clinical Trials, the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 7), MEDLINE (from inception to 20 August 2013), EMBASE (from inception to 2013, week 33) and Science Citation Index-Expanded (from 1990 to August 2013); we conducted full-text searches and applied no restrictions by language or publication status.

We considered randomised clinical trials assessing enteral nutrition in patients with acute pancreatitis. We allowed concomitant interventions if they were received equally by all treatment groups within a trial.

Two review authors independently assessed trials for inclusion and extracted data. We performed the analysis using Review Manager 5 (Review Manager 2013) and both fixed-effect and random-effects models. We expressed results as risk ratios (RRs) for dichotomous data, and as mean differences (MDs) for continuous data, both with 95% confidence intervals (CIs). Analysis was based on an intention-to-treat principle.

We included 15 trials (1376 participants) in this review. We downgraded the quality of evidence for many of our outcomes on the basis of high risk of bias. Low-quality evidence suggests that immunonutrition decreases all-cause mortality (RR 0.49, 95% CI 0.29 to 0.80). The effect of immunonutrition on other outcomes from a subset of the included trials was uncertain. Subgrouping trials by type of enteral nutrition did not explain any variation in effect. We found mainly very low-quality evidence for the effects of probiotics on the main outcomes. One eligible trial in this comparison reported a higher rate of serious adverse events leading to increased organ failure and mortality due to low numbers of events and low risk of bias. When we excluded this study as a post hoc sensitivity analysis, risks of mortality (RR 0.30, 95% CI 0.10 to 0.84), organ failure (RR 0.74, 95% CI 0.59 to 0.92) and local septic complications (RR 0.40, 95% CI 0.22 to 0.72) were lower with probiotics. In one trial assessing immunonutrition with probiotics and fibres, no deaths occurred, but hospital stay was shorter with immunonutrition (MD -5.20 days, 95% CI -8.73 to -1.67). No deaths were reported following semi-elemental enteral nutrition (EN), and the effect on length of hospital stay was small (MD 0.30 days, 95% CI -0.82 to 1.42). Fibre-enriched formulations reduced the number of other local complications (RR 0.52, 95% CI 0.32 to 0.87) and length of hospital stay (MD -9.28 days, 95% CI -13.21 to -5.35) but did not significantly affect all-cause mortality (RR 0.23, 95% CI 0.03 to 1.84) and other outcomes. Very low-quality evidence from the subgroup of trials comparing EN versus no intervention showed a decrease in all-cause mortality with EN (RR 0.50, 95% CI 0.29 to 0.86).

We found evidence of low or very low quality for the effects of immunonutrition on efficacy and safety outcomes. The role of supplementation of enteral nutrition with potential immunomodulatory agents remains in question, and further research is required in this area. Studies assessing probiotics yielded inconsistent and almost contrary results, especially regarding safety and adverse events, and their findings do not support the routine use of EN enriched with probiotics in routine clinical practice. However, further research should be carried out to try to determine the potential efficacy or harms of probiotics. Lack of trials reporting on other types of EN assessed and lack of firm evidence regarding their effects suggest that additional randomised clinical trials are needed. The quality of evidence for the effects of any kind of EN on mortality was low, and further studies are likely to have an impact on the finding of improved survival with EN versus no nutritional support. Evidence remains insufficient to support the use of a specific EN formulation.