Greater Protein and Energy Intake May Be Associated With Improved Mortality in Higher Risk Critically Ill Patients: A Multicenter, Multinational Observational Study

Abstract

Objectives: Controversy exists about the value of greater nutritional intake in critically ill patients, possibly due to varied patient nutritional risk. The objective of this study was to investigate whether clinical outcomes vary by protein or energy intake in patients with risk evaluated by the NUTrition Risk in the Critically Ill score.

Design: Prospective observational cohort.

Setting: A total of 202 ICUs.

Patients: A total of 2,853 mechanically ventilated patients in ICU greater than or equal to 4 days and a subset of 1,605 patients in ICU greater than or equal to 12 days.

Interventions: None.

Measurements and main results: In low-risk (NUTrition Risk in the Critically Ill, < 5) and high-risk (NUTrition Risk in the Critically Ill, ≥ 5) patients, mortality and time to discharge alive up to day 60 were assessed relative to nutritional intake over the first 12 days using logistic regression and Cox proportional hazard regression, respectively. In high-risk but not low-risk patients, mortality was lower with greater protein (4-d sample: odds ratio, 0.93; 95% CI, 0.89-0.98; p = 0.003 and 12-d sample: odds ratio, 0.90; 95% CI, 0.84-0.96; p = 0.003) and energy (4-d sample: odds ratio, 0.93; 95% CI, 0.89-0.97; p < 0.001 and 12-d sample: odds ratio, 0.88; 95% CI, 0.83-0.94; p < 0.001) intake. In the 12-day sample, there was significant interaction among NUTrition Risk in the Critically Ill category, mortality, and protein and energy intake, whereas in the 4-day sample, the test for interaction was not significant. In high-risk but not low-risk patients, time to discharge alive was shorter with greater protein (4-d sample: hazard ratio, 1.05; 95% CI, 1.01-1.09; p = 0.01 and 12-d sample: hazard ratio, 1.09; 95% CI, 1.03-1.16; p = 0.002) and energy intake (4-d sample: hazard ratio, 1.05; 95% CI, 1.01-1.09; p = 0.02 and 12-d sample: hazard ratio, 1.09; 95% CI, 1.03-1.16; p = 0.002). In the 12-day sample, there was significant interaction among NUTrition Risk in the Critically Ill category, time to discharge alive, and protein and energy intake, whereas in the 4-day sample, the test for interaction was not significant.

Conclusions: Greater nutritional intake is associated with lower mortality and faster time to discharge alive in high-risk, longer stay patients but not significantly so in nutritionally low-risk patients.