Refeeding syndrome risk at ICU admission is an independent predictor of ICU readmission but it is not associated with mortality or length of stay in critically ill patients

This study evaluated the association between refeeding syndrome (RFS) risk and intensive care unit (ICU)/in-hospital mortality and length of stay (LOS) and ICU readmission in critically ill patients. This secondary analysis of a cohort study included patients aged ≥ 18 years admitted at ICU 24 h before data collection. We evaluated RFS risk based on the National Institute for Health and Clinical Excellence (NICE), stratifying it into four categories (no, low, high, and very-high risk). Five adult ICUs in Brazil. ICU/in-hospital mortality and LOS and ICU readmission data were obtained from electronic medical records analysis, following patients until discharge (alive or not). The study involved 447 patients, categorized into no (19.2 %), low (28.6 %), high (48.8 %), and very-high (3.4 %) RFS risk groups. No significant differences emerged between the two groups (at RFS risk and no RFS risk) regarding the ICU death ratio (34.3 % versus 23.4 %) and LOS (5 versus 4 days), respectively. In contrast, patients at RFS risk experienced higher in-hospital mortality rates (34.3 % versus 23.4 %) prolonged hospital LOS (21 days versus 17 days), and increased ICU readmission rates (15 % versus 8.4 %) than patients without RFS risk. After adjusting for age and Sequential Organ Failure Assessment (SOFA) Score, we found no association between RFS risk and increased mortality in the ICU or hospital. Also, there was no significant association between RFS risk and prolonged LOS in the ICU or hospital setting. However, patients identified as at risk of RFS showed nearly double the odds of ICU readmission (Odds ratio, 1.90; 95 % CI 1.02–3.43). This study found no significant association between RFS risk and increased mortality in both the ICU and hospital settings, nor was there a significant association with prolonged LOS in the ICU or hospital among critically ill patients. However, patients at risk of RFS exhibited nearly double the odds of ICU readmission. Our findings may contribute to understanding risks associated with ICU readmissions, highlighting the complexity of discharge decision-making through comprehensive assessments.