Greater Protein and Energy Intake for Improving Mortality in Higher Risk Critically Ill Patients: Useful or Useless?
Some investigators have suggested that greater energy intake is harmful (2), whereas others find benefit in greater protein or energy intake (3) against various negative clinical outcomes. Compher et al (1) wisely note that in a large, diverse sample of patients who stay in the ICU at least 12 days, lower mortality and shorter TDA are associated with greater protein and energy intake in the high NUTRIC group but not significantly in the low NUTRIC group patients. Lower mortality and shorter TDA were also associated with increased protein and energy intake in the 4-day sample in high-risk but not low-risk patients, but the test for interaction was not significant.
In this article, the authors suggested that more successful delivery of goal protein and energy intake is associated with the strongest improvement in clinical outcomes in longer stay, high-risk patients. We want to know why the authors did not perform subgroup analysis according to different etiologies of these critically ill patients. Although Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment describe severity of disease, they may not describe mortality risk adequately in such a diverse ICU sample where differences in nutrition support practice. How did the authors evaluate the physiologic state of these patients accurately? For these included patients, the maximum intake was 150% of goal, and few patients received either protein or energy greater than 100% of goal. The difference of actual values is so large, whether they will affect the results?
Finally, we believe the research by Compher et al (1) will promote further researches on the relationship of protein or energy intake and mortality in higher risk critically ill patients.