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

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.