Hypocaloric versus normocaloric nutrition in critically ill patients: a real-world study of a large database MIMIC-IV. 

Abstract

Background Nutritional therapy is essential for patients in the intensive care unit (ICU), when optimal caloric goals remain controversial, especially for the late acute phase (after day 3). This study aimed to investigate the impact of hypocaloric versus normocaloric feeding in this period. Methods We conducted a retrospective analysis within an up-to-date large database, including adult patients who were admitted to a tertiary hospital from 2008 to 2019, and stayed in the ICU for over one week. Individuals were divided according to the mean daily caloric intake from day 4 to day 7 (< 20 Kcal/kg/d; >= 20 Kcal/kg/d). The restricted cubic spline for a cox proportional hazards model was employed to assess the association between mean caloric intake divided by predicted energy expenditure (EE) and 1-year mortality. Results 3,545 eligible patients formed the study population. Most patients received progressively-elevating nutrition, achieving median values of 18.4 Kcal/kg/d and 0.71 g/kg/d in caloric and protein intake from day 4 onwards. Hypocaloric feeding was correlated with reduced nosocomial infection (41.7% vs 46.7%, P = 0.003), hyperglycemia episodes (63.6% vs 67.8%, P = 0.008), ventilation durations (3.6 vs 4.1 days, P = 0.001), and ICU length of stay (LOS) (11.6 vs 13.4 days, P < 0.001) compared to normal energy provision. In-hospital and 1-year mortality risks displayed no significant changes between the two strategies (ORs [95% CIs]: 0.80 [0.61–1.04], P = 0.10; 0.81 [0.64–1.02], P = 0.08, respectively). Achieving a calorie/EE of 40 ~ 70% showed a great 1-year survival benefit when predicted equations were used. Conclusion Compared to normocaloric feeding after day 3, hypocaloric feeding significantly reduced nosocomial infection rate, hyperglycemia episodes, ventilation days, and ICU LOS, when no significant changes were observed in the hospital and 1-year mortality risks. The optimal goal might be set at 40 ~ 70% of EE when predicted equations were used to prevent overfeeding.