How does adequacy of caloric and protein intake associate with the clinical outcomes in critically ill adults of high nutritional risk?

Abstract

Background: Nutritional therapy forms an important part of management among critically ill patients. The modified NUTrition Risk in the Critically Ill (mNUTRIC) score is one of the nutrition evaluation tools developed especially for this special group of patients. This study aims to examine any associations between nutritional adequacy and various clinical outcomes among critically ill adult patients of high nutritional risk in Hong Kong. Methods: This was a retrospective single-centered cross-sectional study conducted in a mixed medical-surgical adult Intensive Care Unit (ICU) of Queen Elizabeth Hospital, a 2, 000-bed major acute public hospital in Hong Kong. All patients admitted between January and December 2017 who fulfilled the exclusion criteria, had an mNUTRIC score of 5 to 9, and had at least three nutrition evaluable days were recruited. Based on their caloric and protein adequacy, they were divided into low (both were less than two thirds), medium (either was two thirds or more) and high (both were two thirds or more) nutritional subgroup. Associations with mortality and other clinical outcomes were examined. Results: Among 215 patients analysed, majority (70.7%) had low nutritional adequacy (caloric adequacy 38.7%±13.7%, protein adequacy 39.7%±17.3%). The all-cause 60-day mortality did not differ significantly among the three nutritional subgroups, and it had no significant association with different levels of nutritional adequacy. Those in the high nutritional subgroup were significantly more likely to have prolonged mechanical ventilation of 7 days or more (58.6% vs. 78.6% vs. 85.7%, P<0.005) and the strength of association was moderate (Cramer's V =0.23). Conclusions: Critically ill patients of high nutritional risk were often given a low level of nutritional support during the acute phase of ICU care. There was no significant difference in all-cause 60-day mortality or correlation with different levels of nutritional adequacy. The chance of prolonged mechanical ventilation was significantly higher among those of high nutritional adequacy with a moderate strength of association.