Identifying critically-ill patients who will benefit most from nutritional therapy: Further validation of the "modified NUTRIC" nutritional risk assessment tool.
Better tools are needed to assist in the identification of critically ill patients most likely to benefit from artificial nutrition therapy. Recently, the Nutrition Risk in Critically ill (NUTRIC) score has been developed for such purpose. The objective of this study was to externally validate a modified version of the NUTRIC score in a second database. We conducted a post hoc analysis of a database of a randomized control trial of intensive care unit (ICU) patients with multi-organ failure. Data for all variables of the NUTRIC score with the exception of IL-6 levels were collected. These included age, APACHE II score, SOFA score, number of co-morbidities, days from hospital admission to ICU admission. The NUTRIC score was calculated using the exact same thresholds and point system as developed previously except the IL-6 item was omitted. A logistic model including the NUTRIC score, the nutritional adequacy and their interaction was estimated to assess if the NUTRIC score modified the association between nutritional adequacy and 28-day mortality. We also examined the association of elevated NUTRIC scores and 6-month month mortality and the interaction between NUTRIC score and nutritional adequacy. A total of 1199 patients were analyzed. The mean total calories prescribed was 1817 cal (SD 312) with total mean protein prescribed of 98.3 g (SD 23.6). The number of patients who received PN was 9.5%. The overall 28-day mortality rate in this validation sample was 29% and the mean NUTRIC score was 5.5 (SD 1.6). Based on the logistic model, the odds of mortality at 28 days was multiplied by 1.4 (95% CI, 1.3-1.5) for every point increase on the NUTRIC score. The mean (SD) nutritional adequacy was 50.2 (29.5) with an interquartile range from 24.8 to 74.1. The test for interaction confirmed that the association between nutritional adequacy and 28-day mortality is significantly modified by the NUTRIC score (test for interaction p = 0.029). In particular, there is a strong positive association between nutritional adequacy and 28 day survival in patients with a high NUTRIC score but this association diminishes with decreasing NUTRIC score. Higher NUTRIC scores are also significantly associated with higher 6-month mortality (p < 0.0001) and again the positive association between nutritional adequacy and 6 month survival was significantly stronger (and perhaps only present) in patients with higher NUTRIC score (test for interaction p = 0.038). The NUTRIC scoring system is externally validated and may be useful in identifying critically ill patients most likely to benefit from optimal amounts of macronutrients when considering mortality as an outcome.