Normocaloric versus hypocaloric feeding on the outcomes of ICU patients: a systematic review and meta-analysis

Current clinical practice guidelines recommend providing ICU patients a daily caloric intake estimated to match 80-100 % of energy expenditure (normocaloric goals). However, recent clinical trials of intentional hypocaloric feeding question this approach. We performed a systematic review and meta-analysis to compare the outcomes of ICU patients randomized to intentional hypocaloric or normocaloric goals. We included randomized controlled trials that enrolled ICU patients and compared intentional hypocaloric with normocaloric nutritional goals. We included studies that evaluated both trophic feeding as well as permissive underfeeding. Data sources included MEDLINE, Cochrane Register of Controlled Trials and citation review of relevant primary and review articles. The outcomes of interest included hospital acquired infection, hospital mortality, ICU length of stay (LOS) and ventilator-free days (VFDs). Six studies which enrolled 2517 patients met our inclusion criteria. The mean age and body mass index (BMI) across the studies were 53 +/- A 5 years and 29.1 +/- A 1.5 kg/m(2), respectively. Two studies compared normocaloric feeding (77 % of goal) with trophic feeding (20 % of goal), while four studies compared normocaloric feeding (72 % of goal) with permissive underfeeding (49 % of goal). Overall, there was no significant difference in the risk of infectious complications (OR 1.03; 95 % CI 0.84-1.27, I (2) = 16 %), hospital mortality (OR 0.91; 95 % CI 0.75-1.11, I (2) = 8 %) or ICU LOS (mean difference 0.05 days; 95 % CI 1.33-1.44 days; I (2) = 37 %) between groups. VFDs were reported in three studies with no significant difference between the normocaloric and intentional hypocaloric groups (data not pooled). This meta-analysis demonstrated no difference in the risk of acquired infections, hospital mortality, ICU length of stay or ventilator-free days between patients receiving intentional hypocaloric as compared to normocaloric nutritional goals.