Impact of caloric intake in critically ill patients with, and without, refeeding syndrome: A retrospective study

Refeeding syndrome comprises metabolic disturbances that occur after the reintroduction of feeding after prolonged fasting. Standard care consists of correcting fluid and electrolytes imbalances. Energy intake during refeeding syndrome is heavily debated. This study addresses the effect of caloric intake on outcome during the management of refeeding syndrome.

A retrospective study among critically ill invasive mechanically ventilated patients admitted for >7 days to a medical-surgical ICU. Refeeding syndrome was diagnosed by the occurrence of new onset hypophosphatemia (<0.65 mmol/l) within 72 h of the start of nutritional support. Primary outcome was 6-month mortality. Secondary outcomes were 3-month mortality, ICU and hospital length of stay and duration of mechanical ventilation. Outcomes of patients with and without refeeding syndrome were compared and subgroup analysis on energy intake within the refeeding population was performed for the duration of survival.

Of 337 enrolled patients, 124 (36.8%) developed refeeding syndrome and 213 patients (63.2%) maintained normal serum phosphate levels. Between the two groups, no statistical significant differences in clinical outcomes were observed. Within the refeeding syndrome group, a reduced 6-month mortality risk for low caloric intake (<50% of target) was seen compared with normal intake, adjusted Hazard Ratio 0.39, (95% CI 0.16-0.95, p = 0.037). In this group, low caloric intake was associated with an increased overall survival time at day 180 (153.0 (SE 10.1) vs 119.1 (SE 8.0) days, log-rank p = 0.018).

Refeeding syndrome is common among prolonged mechanically ventilated critically ill patients, however not predictable by baseline characteristics. Among patients that develop refeeding syndrome low caloric intake was associated with a reduction in 6-month mortality risk. This effect was not seen in patients without refeeding syndrome. Findings support caloric restriction in refeeding syndrome during critical illness.