Current evidence on ω-3 fatty acids in enteral nutrition in the critically ill: A systematic review and meta-analysis

Fish oil exerts anti-inflammatory and immunomodulatory properties that may be beneficial for critically ill patients, thus multiple randomized controlled trials and meta-analyses have been performed. However, controversy remains as to whether fish oil-enriched enteral nutrition can improve clinical outcomes in adult critically ill patients in intensive care units (ICUs). The aim of this study was to provide an up-to-date systematic review and meta-analysis of all randomized controlled trials of fish oil-containing enteral nutrition addressing relevant clinical outcomes in critically ill patients. A systematic literature search was conducted. The primary outcome was 28-d mortality. Secondary outcomes were ICU and hospital mortality, ICU and hospital length of stay (LOS), ventilation duration, and infectious complications. Predefined subgroup and sensitivity analyses were performed. Twenty-four trials, enrolling 3574 patients, met the inclusion criteria. The assessment of risk for bias showed that most of included studies were of moderate quality. The overall results revealed no significant effects of enteral fish oil supplementation on 28-d, ICU or hospital mortality. However, ICU LOS and ventilation duration were significantly reduced in patients receiving fish oil supplementation. Furthermore, subgroup analysis revealed a significant reduction in 28-d mortality, ICU LOS, and ventilation duration in patients with acute respiratory distress syndrome but not in other subgroups. When comparing high- and low-quality trials, significant reductions in 28-d mortality and ventilation duration in low-quality trials only were observed. Regarding ICU LOS a significant reduction was observed in high-quality trials; whereas only a trend was observed in low-quality trials. No significant effects on hospital LOS or infectious complications were observed in overall or subgroup analyses. Enteral fish oil supplementation cannot be recommended for critically ill patients, as strong scientific evidence for improved clinical benefits was not found. There is a signal of mortality benefit in patients with acute respiratory distress syndrome; however, results are based on low-quality studies. Further research should focus on the relation between the individual critically ill patients' immune response, the administration of fish oil, and clinical outcomes.