The association of macronutrient deficit with functional status at discharge from the intensive care unit: a retrospective study from a single-center critical illness registry.

Background: Nutrition is often thought to influence outcomes in critically ill patients. However, the relationship between macronutrient delivery and functional status is not well characterized. Our goal was to investigate whether caloric or protein deficit over the course of critical illness is associated with functional status at the time of intensive care unit (ICU) discharge.

Methods: We performed a retrospective analysis of surgical ICU patients at a teaching hospital in Boston, MA. To investigate the association of caloric or protein deficit with Functional Status Score for the ICU (FSS-ICU), we constructed linear regression models, controlling for age, sex, race, body mass index, Nutritional Risk in the Critically Ill score, and ICU length of stay. We then dichotomized caloric as well as protein deficit, and performed logistic regressions to investigate their association with functional status, controlling for the same variables.

Results: Linear regression models (n = 976) demonstrated a caloric deficit of 238 kcal (237.88; 95%CI 75.13-400.63) or a protein deficit of 14 g (14.23; 95%CI 4.46-24.00) was associated with each unit decrement in FSS-ICU. Logistic regression models demonstrated a 6% likelihood (1.06; 95%CI 1.01-1.14) of caloric deficit ≥6000 vs. <6000 kcal and an 8% likelihood (1.08; 95%CI 1.01-1.15) of protein deficit ≥300 vs. <300 g with each unit decrement in FSS-ICU.

Conclusion: In our cohort of patients, macronutrient deficit over the course of critical illness was associated with worse functional status at discharge. Future studies are needed to determine whether optimized macronutrient delivery can improve outcomes in ICU survivors.