RESUMEN
BACKGROUND: Patients in the intensive care unit (ICU) are at high risk for refeeding syndrome (RFS), yet there is uncertainty regarding how RFS should be operationalized in the ICU. We evaluated different definitions for RFS and tested how they associated with patient-centered outcomes in the ICU. METHODS: This was a retrospective comparison study. Patients age ≥18 years were eligible if they were newly initiated on enteral feeding while hospitalized in the ICU. Eight definitions for RFS were operationalized, including that from the American Society for Parenteral and Enteral Nutrition (ASPEN), all based on electrolyte levels from immediately before until up to 5 days after the initiation of enteral nutrition. Patients were followed for death or for ICU-free days, a measure of healthcare utilization. RESULTS: In all, 2123 patients were identified, including 406 (19.1%) who died within 30 days of ICU admission and 1717 (80.9%) who did not. Prevalence of RFS varied from 1.5% to 88% (ASPEN definition) depending on the RFS definition used. The excess risk for death associated with RFS varied from 33% to 92% across definitions. The development of RFS based on the ASPEN definition was associated with a greater decrease in ICU-free days compared with other definitions, but the relationship was not statistically significant. CONCLUSION: Eight definitions for RFS were evaluated, none of which showed strong associations with death or ICU-free days. It may be challenging to achieve a standardized definition for RFS that is based on electrolyte values and predicts mortality or ICU-free days.