Permissive underfeeding and intensive insulin therapy in critically ill patients: a randomized controlled trial

Background: Nutritional support has been recognized as an essential part of intensive care unit management. However, the appropriate caloric intake for critically ill patients remains ill defined. Objective: We examined the effect of permissive underfeeding compared with that of target feeding and of intensive insulin therapy (IIT) compared with that of conventional insulin therapy (CIT) on the outcomes of critically ill patients. Design: This study had a 2 x 2 factorial, randomized, controlled design. Eligible patients were randomly assigned to permissive underfeeding or target feeding groups (caloric goal: 60-70% compared with 90-100% of calculated requirement, respectively) with either IIT or CIT (target blood glucose: 4.4-6.1 compared with 10-11.1 mmol/L, respectively). Results: Twenty-eight-day all-cause mortality was 18.3% in the permissive underfeeding group compared with 23.3% in the target feeding group (relative risk: 0.79; 95% CI: 0.48, 1.29; P = 0.34). Hospital mortality was lower in the permissive underfeeding group than in the target group (30.0% compared with 42.5%; relative risk: 0.71; 95% CI: 0.50, 0.99; P = 0.04). No significant differences in outcomes were observed between the IIT and CIT groups. Conclusion: In critically ill patients, permissive underfeeding may be associated with lower mortality rates than target feeding. This trial was registered at controlled-trials.com as ISRCTN96294863. Am J Clin Nutr 2011;93:569-77.