Impact of early high protein intake in critically ill patients: a randomized controlled trial

BACKGROUND: Conflicting findings regarding the impact of High protein intake during the early phase in critically ill patients have been reported. Therefore, we aimed to assess the influence of higher early protein intake on the prognosis of critically ill patients. METHODS: This randomized controlled trial involved 173 critically ill patients who stayed in the Intensive Care Unit/Emergency ICU (ICU/EICU) for at least 7 days. The Low group (n = 87) and High group (n = 86) received protein supplementation of 0.8 g/kg.d and 1.5 g/kg.d, respectively, within 1-3 days of enteral nutrition (EN) initiation, with both groups transitioning to 1.5 g/kg.d on the 4th day. The serum prealbumin (PA), blood urea nitrogen/creatinine, and rectus femoris muscle thickness and cross-sectional area of all patients was measured on the 1th, 3rd, 5th, 7th day, and the day of ICU/EICU discharge. RESULTS: Patients in both Low and High groups showed no significant differences in age, APACHE II scores, or other demographic and baseline characteristics. There were also no significant differences in the primary outcome (28-day mortality rate) and secondary outcomes (incidence rate of refeeding syndrome and EN tolerance score) between the two groups. However, the Low group exhibited a significantly higher 28-day mortality rate (HR = 2.462, 95% CI: 1.021-5.936, P = 0.045) compared to High group, as determined by Cox proportional hazards models incorporating the time factor. The High group exhibited significantly shorter durations of mechanical ventilation and ICU stay compared to the Low group. Serum PA levels were higher, and rectus femoris muscle atrophy rates were lower in the High group. Furthermore, for septic patients, high protein intake significantly reduced the 28-day mortality rate despite a small sample size (n = 34). CONCLUSIONS: Our study indicates that increasing early protein intake to 1.5 g/kg.d may be safe and help improve the nutritional status and prognosis of critically ill patients. TRIAL REGISTRATION: This study was registered with the Chinese Clinical Trial Registry (ChiCTR2000039997, https://www.chictr.org.cn/ ).