Timing of Achieving 70% of Energy Requirements in Critically Ill Patients: Association with In-Hospital Mortality and...

Background/Objectives: The European Society for Clinical Nutrition and Metabolism recommends avoiding full feeding during the first 48-72 h of critical illness and gradually achieving 70-100% of energy requirements within the first week. However, the clinical significance of achieving approximately 70% of estimated energy requirements by day 7 in the intensive care unit (ICU) remains unclear in routine practice. This study investigated whether achieving ≥70% of estimated energy requirements by day 7 was associated with in-hospital mortality and explored clinical factors associated with achieving this target. Methods: This retrospective study included critically ill patients who remained in the ICU through day 7 and had complete nutritional data for the first 7 ICU days. Cox proportional hazards regression was performed in a day-7 landmark cohort to investigate the association between day-7 energy adequacy and subsequent in-hospital mortality. Logistic regression analysis was performed to identify the factors associated with achieving ≥70% of estimated energy requirements by day 7. Results: Among 507 patients in the day-7 landmark cohort, 355 achieved ≥70% of estimated energy requirements by ICU day 7, and 152 did not. Achievement of the day-7 target was associated with lower in-hospital mortality (adjusted hazard ratio [aHR] 0.50, 95% CI 0.30-0.84; p = 0.008), whereas achievement of the same target by day 3 was not significantly associated with in-hospital mortality. Older age and elevated serum albumin levels were independently associated with achieving the day-7 target. In exploratory subgroup analyses, the point estimates were directionally similar across clinically relevant subgroups, but no statistically significant interaction was observed. Conclusions: Achievement of ≥70% of estimated energy requirements by ICU day 7 was associated with lower in-hospital mortality, whereas achievement of the same target by day 3 was not significantly associated with in-hospital mortality. These findings should be interpreted as observational and hypothesis-generating.