Purpose: The objective of this study was to examine the relationship between the amount of energy and protein administered and clinical outcomes, and the extent to which pre-morbid nutritional status influenced this relationship.
Methods: We conducted an observational cohort study of nutrition practices in 167 intensive care units (ICUs) across 21 [corrected] countries. Patient demographics were collected, and the type and amount of nutrition received were recorded daily for a maximum of 12 days. Patients were followed prospectively to determine 60-day mortality and ventilator-free days (VFDs). We used body mass index (BMI, kg/m2) as a marker of nutritional status prior to ICU admission. Regression models were developed to evaluate the relationship between nutrition received and 60-day mortality and VFDs, and to examine how BMI modifies this relationship.
Results: Data were collected on 2,772 mechanically ventilated patients who received an average of 1,034 kcal/day and 47 g protein/day. An increase of 1,000 cal per day was associated with reduced mortality [odds ratio for 60-day mortality 0.76; 95% confidence intervals (CI) 0.61-0.95, p = 0.014] and an increased number of VFDs (3.5 VFD, 95% CI 1.2-5.9, p = 0.003). The effect of increased calories associated with lower mortality was observed in patients with a BMI <25 and > or =35 with no benefit for patients with a BMI 25 to <35. Similar results were observed when comparing increasing protein intake and its effect on mortality.
Conclusions: Increased intakes of energy and protein appear to be associated with improved clinical outcomes in critically ill patients, particularly when BMI is <25 or > or =35.