Differential Effects of Early Energy and Protein Inadequacies on the Outcome of Critically Ill Patients

Abstract

Background: Differential effects of energy and protein inadequacies of intensive care unit (ICU) patients in first 72 hours are unknown.

Methods: We included all adult patients receiving mechanical ventilation (MV) > 72 hours between August 2012 and December 2014. Energy and protein doses were 25 kcal/kg/day and 1.5 g/kg/day, respectively. We used multivariable Cox regression analysis for 28-day mortality and competing risks regression analysis for post-ICU length of stay (LOS) in hospital survivors.

Results: In 421 patients (male 63.4%, mean age 62 ± 15.1 years) the energy and protein adequacies at 72 hours were 70% and 56%, respectively. Non-survivors by day 28 were started on feeding significantly later (median, 14.13 (5.48-33.78) versus 9.25 (5.45-16.58) hours, P = .003) and received lower energy (mean, 0.57 ± 0.36 versus 0.76 ± 0.29, P < 0.001) and protein (median, 0.51 (0.13-0.74) versus 0.61 (0.40-0.84), P < 0.001) adequacies at day 7 (same effect seen at 72 hours, P < 0.001). Higher energy adequacy at 72 hours was associated with lower mortality (hazard ratio [HR], 0.39 (95% CI 0.20-0.75), P = 0.004); the lowest mortality was seen between 61% and 70% energy adequacies. No such association was seen with protein adequacy. In 280 hospital survivors, higher energy adequacy at 72 hours (subdistribution HR 1.63; 95% CI, 1.06-2.50, P = 0.025) was significantly associated with shorter post-ICU LOS. No such effect was seen with protein adequacy.

Conclusion: Higher energy but not protein adequacy at 72 hours of MV was associated with improved patient-centric outcomes.

Keywords: critical illness; energy; enteral nutrition; intensive care unit; mortality; protein.