High Dose of Protein Affects Mortality in Critically Ill Patients if They Do Not Have Sepsis

Introduction

Optimal energy intake is very important in the early phase of critical illness. Some studies indicate that so-called trophic feeding with low energy content does not worsen patient survival. On the other hand, early overfeeding can adversely affect patient prognosis. Additional observational studies confirmed that protein intake at a dose of 1.2–1.5 g/kg/day is associated with lower mortality. It was also found that the cumulative amount of proteins/amino acids during ICU stay was linked with prolonged recovery. There is a hypothesis that early high protein intake inhibits autophagy, which supports intracellular bacteria removal, thus affecting outcomes in sepsis patients. Diverging opinions led authors to conduct a prospective observational study.

Study Goals

The primary goal of the study was to prove the benefit of early protein intake at a dose > 1.2 g/kg/day, recommended by the European Society for Clinical Nutrition and Metabolism (ESPEN). Furthermore, it aimed to determine whether early high protein intake could negatively impact sepsis patients and whether early energy overfeeding could worsen patient outcomes, thereby obscuring the positive effect of early high-protein intake.

Patient Population

The study included patients hospitalized from 2004–2010 in the ICU of a university hospital in Amsterdam, Netherlands. These were hemodynamically stable, mechanically ventilated critically ill individuals with prolonged ventilation time (> 72 hours), enrolled between the 3rd and 5th day of ICU stay. Artificial nutrition for at least the following 5–7 days was anticipated for all. Other inclusion criteria were indirect calorimetry upon ICU admission, age > 18 years, and the individual's first ICU stay.

Evaluated Parameters

Logistic regression analysis was used to assess the relationship between protein intake on the 4th ICU day (cutoff amounts were 0.8 or 1.0 or 1.2 g/kg), energy excess (calculated as the ratio of energy intake to measured energy expenditure, with an excess defined as a ratio > 1.1), and a sepsis diagnosis upon admission with mortality, adjusted for APACHE II scores (Acute Physiology and Chronic Health Evaluation II).

Findings

The study included a total of 843 patients, 117 of whom had sepsis. Of the 736 non-septic patients, 307 had excessive energy intake. Average protein intake on the 4th hospital day was 1 g/kg, and hospital mortality was 36%. In the overall patient cohort, protein intake on the 4th ICU day (odds ratio [OR] 0.85; 95% confidence interval [CI] 0.73–0.99; p = 0.047), energy overfeeding (OR 1.62; 95% CI 1.07–2.44; p = 0.022), and presence of sepsis (OR 1.77; 95% CI 1.18–2.65; p = 0.005) were independent risk factors for mortality beyond APACHE II scores.

In patients with sepsis or energy overfeeding, protein intake on the 4th ICU day was not associated with mortality. For patients without sepsis and without energy overfeeding (n = 419), mortality decreased with higher protein intake (37% at < 0.8 g/kg, 35% at 0.8–1.2 g/kg, 27% at 1.0–1.2 g/kg, and 19% at ≥ 1.2 g/kg; p = 0.033). In the subgroup of patients with protein intake > 1.2 g/kg, the association with low mortality was statistically significant (OR 0.42; 95% CI 0.21–0.83; p = 0.013).

Conclusion

The study concluded that in critically ill non-septic patients, early high protein intake was associated with lower mortality, whereas early energy overfeeding contributed to increased mortality. However, the positive effect of early high protein intake on mortality was not proven for septic patients.

(moa)

Source: Weijs P. J., Looijaard W. G., Beishuizen A. et al. Early high protein intake is associated with low mortality and energy overfeeding with high mortality in non-septic mechanically ventilated critically ill patients. Crit Care 2014; 18 (6): 701, doi: 10.1186/s13054-014-0701-z.