Outcomes used in randomised controlled trials of nutrition in the critically ill: a systematic review.

BACKGROUND: No evidence exists to date on which to base the selection of outcome measures for assessing nutritional interventions in critically ill patients. We conducted a systematic literature review to describe the outcomes used in recent randomised controlled trials (RCTs) assessing nutritional interventions in critically ill patients. Our objective was to set the foundation for the development of a core set of outcome measures for use in future RCTs. METHODS: We searched the PubMed/MEDLINE, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov databases for RCTs of nutritional interventions in critically ill patients aged 18 years or older, published and/or registered between January 2000 and August 2018. Outcomes were divided into six categories (mortality, length of stay, duration of organ dysfunction, complications, functional outcomes, and others) and analysed according to the study characteristics and publication year. RESULTS: Of the 885 references retrieved, 170 were included in the review. Of these, 136 (80%) defined a primary outcome, 114 (67%) defined secondary outcomes (two per study on average), and 34 (20%) did not specify whether outcomes were primary or secondary. We identified 24 different outcomes in all, of which 19 were primary. Complications were the most widely used primary outcome (65/136, 48%). Mortality was the primary outcome in 17/136 (13%) studies, with six different timepoints. The main secondary outcomes were length of stay (90/114, 79%), mortality (82/114, 72%), and duration of organ dysfunction (75/114, 65%). CONCLUSIONS: This systematic review highlights the heterogeneity of outcomes used in recent randomized controlled trials evaluating nutritional interventions in critically ill patients. The results of our systematic review may have implications for designing future RCTs of nutritional interventions in the ICU.

Dual effects of a high-protein diet on DSS-treated mice during colitis resolution phase.

The impact of the dietary protein level on the process of colonic mucosal inflammation and subsequent recovery remains largely unknown. In this study, we fed DSS-treated mice with either a normoproteic (NP) or a high-protein (HP) isocaloric diet from the beginning of the 5-day dextran sulfate sodium (DSS) treatment to 14 days later. Measurements of colitis indicators (colon weight:length ratio, myeloperoxidase activity, cytokine expressions) showed a similar level of colonic inflammation in both DSS groups during the colitis induction phase. However, during the colitis resolution phase, inflammation intensity was higher in the DSS-HP group than in the DSS-NP group as evidenced by higher inflammatory score and body weight loss. This coincided with a higher mortality rate. In surviving animals, an increase in colonic crypt height associated with a higher number of colon epithelial cells per crypt, and TGF-ß3 content was observed in the DSS-HP vs. DSS-NP group. Moreover, colonic expression patterns of tight junction proteins and E-cadherin were also different according to the diet. Altogether, our results indicate that the HP diet, when given during both the induction and resolution periods of DSS-induced colitis, showed deleterious effects during the post-induction phase. However, HP diet ingestion was also associated with morphological and biochemical differences compatible with higher colonic epithelium restoration in surviving animals, indicating an effect of the dietary protein level on colonic crypt repair after acute inflammation. These data highlight the potential impact of the dietary protein amount during the colitis course.