Our data suggest that although overall low protein intake is associated with the highest mortality risk, high protein intake during the first 3-5 days of ICU stay is also associated with increased long-term mortality. Therefore, timing of high protein intake may be relevant for optimizing ICU, in-hospital and long-term mortality outcomes.

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.

Background The optimal nutritional support for critically ill septic patients remains unknown. This study evaluates the associations of macronutrient intake during the first week of intensive care unit (ICU) admission and long‐term clinical outcomes in septic and non‐septic patients. Methods Prolonged mechanically ventilated patients were retrospectively studied. The association of protein (low: <0.8 g/kg/d, medium: 0.8–1.2 g/kg/d, high >1.2 g/kg/d) and energy intake (<80%, 80%–110%, 110% of target) during days 1–3 and 4–7 after ICU admission and 6‐month mortality was analyzed for septic and non‐septic patients separately. Results A total of 423 patients were investigated. Of these, 297 had sepsis. In the sepsis group, medium protein intake at days 4–7 was associated with lower 6‐month mortality (hazard ratio [HR]: 0.646, 95% confidence interval [CI]: 0.418‐0.996, P=0.048) compared with high intake. In the non‐sepsis group, early high and late low protein intake were associated with higher 6‐month mortality (HR: 3.902, 95% CI: 1.505‐10.115, P=0.005; HR: 2.642, 95% CI: 1.128‐6.189, P=0.025) compared with low and high protein intake, respectively. For energy intake, late energy intake of >110% was associated with decreased mortality in septic patients (HR: 0.400, 95% CI: 0.222‐0.721, P=0.002), whereas in non‐septic patients, late medium energy intake (80%–110%) was associated with better survival (HR: 0.379, 95% CI: 0.175‐0.820, P=0.014), both compared with low energy intake. Conclusion Divergent associations of macronutrient intake were found; early high protein intake in non‐septic patients, but not in septic patients, was found to be associated with higher 6‐month mortality.