Macronutrient intake and outcomes of ICU patients with refeeding hypophosphatemia

Normocaloric vs. calorie-restricted feeding in Intensive Care Unit (ICU) patients with refeeding hypophosphatemia (RH) is associated with increased mortality rates. Until now, only total energy provision has been studied. Data on individual macronutrients (proteins, lipids, and carbohydrates) and clinical outcomes are lacking. This study evaluates associations between macronutrient intake among RH patients during the first week of ICU admission and clinical outcomes. Methods: A single-centre retrospective observational cohort study was conducted among prolonged mechanically ventilated RH ICU patients. The primary outcome was the association of separate macronutrient intakes during the first week of ICU admission with 6-month mortality, adjusted for relevant variables. Other parameters included ICU-, hospital- and 3-month mortality, mechanical ventilation duration and length of ICU and hospital stay. Macronutrient intakes were subsequently analyzed during day 1–3 and day 4–7 of ICU admission. Results: In total, 178 RH patients were included. Six-month all-cause mortality was 29.8%. Higher protein intake during days 1–3 of ICU admission (>0.71 g/kg∗day; HR 2.224, 95%CI 1.261–3.923, p = 0.006), higher age (HR 1.040, 95%CI 1.015–1.066, p = 0.002) and higher APACHE II scores on ICU admission (HR 1.086, 95%CI 1.034–1.140, p = 0.001) were associated with increased 6-month mortality. No differences in other outcomes were observed. Conclusion: High protein - not carbohydrate or lipid - intake during the first three days of ICU admission in patients with RH is associated with increased 6-month mortality, but not short-term outcomes. We hypothesize a time-dependent and dose–response relationship between protein intake and mortality in refeeding hypophosphatemia ICU patients, although additional (randomized controlled) studies are needed to confirm this hypothesis.