A total of 834 patients in the ICU with sepsis and septic shock were included. The demographic, physiologic, and nutritional data and clinical outcomes of all patients are displayed in Table 1. The mean age was 68.9 years, and 65.5% of patients were male. The mean SOFA and APACHE II scores were 10.8 ± 3.7 and 32.0 ± 8.4, respectively. The mean number of days in which a mechanical ventilator was used was 8.4 ± 23.3 days, and the mean ICU LOS and hospital LOS were 13.2 ± 13.7 and 35.6 ± 42.3 days, respectively.
The most common source of infection was respiratory (57.6%), followed by the gastrointestinal entrance (15.1%). Furthermore, gram-negative pathogens were the most common (32.3%). The in-hospital and 30-day mortality rates were 33.7% (n=281) and 28.8% (n=240), respectively. The mean mNUTRIC score was 6.7±1.7, and 89.9% of patients were in the high-score group (5–9 points). The mean number of days on vasopressors, such as norepinephrine, was 7.1± 9.3 days.
As for the nutrition delivered during first week of sepsis, average daily energy achievements of target energy were 80.0±33.7%, and the average daily protein intake during the first week of sepsis onset was 0.64 ± 0.43 g/kg/day. Figure 1 shows the pattern of daily energy delivery (kcal) via enteral and parenteral feeding, and daily protein intake (g/kg) during the first week of sepsis onset.
Clinical outcomes
In-hospital mortality and nutrition supply
The association of in-hospital mortality and nutrition supply are outlined in Table 2. When analysed using the univariable Cox regression analysis, the average daily protein intake and average energy intake were significantly associated with reduced in-hospital mortality (HR, 0.43; 95% CI, 0.30–0.60; and P <0.001; and HR, 0.93; 95% CI, 0.90–0.96; and P <0.001), respectively. Increases in mNUTRIC (HR, 1.25; 95% CI, 1.16–1.36; and P<0.001), SOFA (HR, 1.14; 95% CI, 1.10–1.18; and P <0.001), and APACHE II scores (HR, 1.05; 95% CI, 1.04–1.07; and P <0.001) were associated with increases in in-hospital mortality. Sex and number of co-morbidities were not significantly associated with in-hospital mortality.
A multivariable Cox regression analysis was performed using the average daily protein intake, average energy intake, and mNUTRIC, SOFA, and APACHE II scores. The increased average daily protein intake during the first week of sepsis onset, mNUTRIC and SOFA scores were associated with reduced in-hospital mortality (HR, 0.55; 95% CI, 0.39–0.78; and P=0.001; HR, 1.11; 95% CI, 1.01–1.23; P=0.039; and HR, 1.07; 95% CI, 1.02–1.12; and p=0.006), respectively.
Comparison of in-hospital mortality between the low and high mNUTRIC score groups
When analysed using the univariable Cox regression analysis, no factor was associated with in-hospital mortality in the low mNUTRIC score group. In contrast, the average daily protein intake and average energy intake were significantly associated with reduced in-hospital mortality in the high mNUTRIC score group, (HR, 0.46; 95% CI, 0.32–0.65; P <0.001; and HR, 0.93; 95% CI, 0.89–0.96; and P<0.001), respectively. Additionally, increases in the SOFA and APACHE II scores were associated with increases in in-hospital mortality (HR, 1.12; 95% CI, 1.08–1.16; and P <0.001; and HR, 1.05; 95% CI, 1.03–1.16; and P<0.001), respectively.
A multivariable Cox regression analysis was performed using the average daily protein intake, average energy intake, and SOFA and APACHE II scores. Increases in daily protein intake during the first week of sepsis onset, and increases in the SOFA, and APACHE II scores were associated with reduced in-hospital mortality in the high mNUTRIC score group, (HR, 0.59; 95% CI, 0.42–0.84; P=0.004; HR, 1.07; 95% CI, 1.02–1.12; and P=0.009; and HR, 1.03; 95% CI, 1.01–1.05; and P=0.015), respectively.
30-day mortality and nutrition supply
The association between 30-day mortality and nutrition supply are outlined in Table 3. A univariate Cox regression analysis has shown that the average daily protein intake, daily energy intake, mNUTRIC, SOFA, and APACHE II scores, and the number of co-morbidities were significantly associated with lower 30-day mortality. Furthermore, increases in daily energy intake was associated with lower 30-day mortality in the multivariable regression analysis after adjusting for mNUTRIC, SOFA, and APACHE II scores, and the number of co-morbidities.
Comparison of 30-day mortality between the low and high mNUTRIC score groups
In the low mNUTRIC score group, there were no associations between protein or energy intake with 30-day mortality. However, in the high mNUTRIC score group, a univariate regression analysis has shown that both daily energy and protein intakes were associated with lower 30-day mortality. Moreover, increased average daily energy intakes were associated with reduced 30-day mortality in the high mNUTRIC score group as a result of a multivariate regression analysis (HR, 0.96; 95% CI, 0.92–1.00; and P=0.026).
Ventilator-free days within 28 days of sepsis onset and nutritional support
A univariate Poisson log linear regression analysis has shown that the average daily protein and energy intakes were not significantly related to the number of ventilator-free days within 28 days of sepsis onset.
Comparison of number of ventilator-free days within 28 days of sepsis onset between the high and low mNUTRIC score group
In the low mNUTRIC score group, the average daily protein and energy intakes were not significantly associated with the number of ventilator-free days within 28 days of sepsis onset on a univariate Poisson log linear analysis. In contrast, patients in the high NUTRIC score group had a significantly longer ventilator-free days within 28 days of sepsis onset when higher daily average energy intakes were administered, as assessed using a Poisson log linear regression analysis. However, a multivariable Poisson log linear regression analysis using the APACHE II and SOFA scores did not demonstrate the aforementioned association.
Length of stay in the ICU and hospital and nutritional support
When analysed using the univariate Poisson log linear regression analysis, the average daily protein intake and energy intake were significantly associated with reduced LOS in the ICU, and in the hospital, (HR, 0.35; 95% CI, 0.22-0.54; and P <0.001; HR, 0.90; 95% CI, 0.90-0.94; and P<0.001), and (HR, 0.48; 95% CI, 0.34-0.67; and P <0.001; HR, 0.93; 95% CI, 0.90-0.97; and P<0.001), respectively. However, a multivariate Poisson log linear regression analysis showed that the amount of energy intake and protein intake were associated with a relatively low ICU LOS.
1-year mortality and route of nutrition delivery
A Kaplan–Meier estimate analysis showed that route of nutrition delivery during the first week of sepsis onset was not associated with 1-year mortality in the group met >70% of their daily energy intake requirement. However, EN with supplemental PN was superior to only EN (P=0.016) or only PN (P=0.042) in the patients who had been underfed (≤70% of energy target) (Figure 2). Cox-regression analysis adjusted with APACHE II score, mNUTRIC score, SOFA score, the number of co-morbidities, and amount of daily energy intake, revealed that during first week of sepsis (P=0.026), EN with supplemental PN was superior to EN in improving 1-year mortality (Table 4).