More Food for Thought: Nutrition, the Nutrition Risk in the Critically Ill Score, and the Dilemma of “Goal” Feeding*

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The field of critical care has a long history of failed attempts at therapies or treatment strategies that were aimed at making a critically ill patient look more like a “normal” patient. Examples include liberal blood transfusion to raise the hematocrit, insulin infusions to achieve “tight” glucose control, increasing minute ventilation and oxygenation to normalize PCO2 and PO2 levels, and numerous others. The common thread among all of these is that they ultimately were found to confer no benefit, or even resulted in significant excess patient morbidity or mortality. The job of an intensivist is often perceived as directing the delivery of a series of treatments or interventions that become increasingly aggressive as the severity of illness increases. In actuality, the delivery of modern high-quality critical care is as much about knowing when to be less aggressive with certain treatments, or even when to withhold therapies that have no benefit or even confer added morbidity. Nutrition in the ICU patient is arguably another example, where the paradigm has slowly shifted from aggressive and early high-calorie feeding in all critically ill patients to a more selective and moderate approach (1). It also remains an almost impossibly complex and often counter-intuitive area of critical care where we, like Shakespeare’s Horatio, are only beginning to scratch the surface of true understanding.
In this issue of Critical Care Medicine, Compher et al (2) report an intriguing analysis of data from the prospective observational International Nutrition Survey 2013. This web-based survey collected detailed nutrition-related information, standard demographic and disease-related variables, and patient outcomes from 4,040 subjects in 202 ICUs. The primary objective of this analysis was to evaluate the utility of the Nutrition Risk in the Critically Ill (NUTRIC) score and whether more aggressive delivery of nutritional therapy was associated with improved outcomes (primarily 60-d mortality) among patients classified as “high risk” by the NUTRIC score. The authors used a modified NUTRIC score (omitting the serum interleukin-6 level used in the original description) and defined the high-risk cohort as those patients with a score of greater than or equal to 5 (range, 0–9). Standard logistic regression models were then created to examine the interaction between the NUTRIC risk category and caloric (or protein) intake on 60-day mortality. For the entire cohort as a whole, they found that there was no significant interaction between the NUTRIC category, amount of protein or total caloric intake, and mortality. However, in the adjusted analyses, they found a relatively consistent relationship between protein or calorie intake and mortality among patients categorized as high risk by the NUTRIC score, whereas there was no significant similar relationship found in the low-risk cohort. For every 10% increase in either protein intake or total caloric intake, there was a corresponding decrease in the mortality ranging from 6.6% to 11.6%. The authors suggest that the NUTRIC score may be a useful metric to identify those ICU patients who are at the highest risk of poor outcomes, and who may benefit from early and more aggressive delivery of full nutritional support. In the conclusions, they support the practice of attempting to feed all ICU patients at goal protein and calorie levels, understanding that those patients with less severe disease or lower NUTRIC scores may receive no additional benefit.
This is an important and very well-done study that attempts to validate the NUTRIC score as not only a valid prognostic measure but also as a clinically useful scoring system that could be used to guide the timing of initiating nutritional support and the aggressiveness of delivering higher levels of protein and energy (calories) (3).
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