There is limited evidence for the association between malnutrition and mortality as well as Intensive Care Unit length-of-stay (ICU-LOS) in critically ill patients. We aimed to examine the aforementioned associations by conducting a prospective cohort study in an ICU of a Singapore tertiary hospital. Between August 2015 and October 2016, all adult patients with ≥ 24 h of ICU-LOS were included. The 7-point Subjective Global Assessment (7-point SGA) was used to determine patients’ nutritional status within 48 h of ICU admission. Multivariable regressions were conducted in two ways: (1) presence versus absence of malnutrition, and (2) dose-dependent association for each 1-point decrease in the 7-point SGA. There were 439 patients of which 28.0% were malnourished, and the 28-day mortality rate was 28.0%. Malnutrition was associated with an increased risk of 28-day mortality (adjusted Relative Risk 1.33 (95% Confidence Interval: 1.05–1.69)), and this risk increased with a greater degree of malnutrition (adjusted Relative Risk 1.08 (95% Confidence Interval: 1.00–1.16) for each 1-point decrease in the 7-point SGA). No significant association was found between malnutrition and ICU-LOS. The results of this study indicated a clear association between malnutrition and higher 28-day mortality in critically ill patients. The association between malnutrition and ICU-LOS could not be replicated and hence requires further evaluation.

The mNUTRIC and SGA had poor agreement. Although they individually provided a fair discriminative value for hospital mortality, the combination of these approaches is a better discriminator to quantify mortality risk.

Background During the initial phase of critical illness, the association between the dose of nutrition support and mortality risk may vary among patients in the intensive care unit (ICU) because the prevalence of malnutrition varies widely (28 to 78%), and not all ICU patients are severely ill. Therefore, we hypothesized that a prognostic model that integrates nutritional status and disease severity could accurately predict mortality risk and classify critically ill patients into low- and high-risk groups. Additionally, in critically ill patients placed on exclusive nutritional support (ENS), we hypothesized that their risk categories could modify the association between dose of nutrition support and mortality risk. Methods A prognostic model that predicts 28-day mortality was built from a prospective cohort study of 440 patients. The association between dose of nutrition support and mortality risk was evaluated in a subgroup of 252 mechanically ventilated patients via logistic regressions, stratified by low- and high-risk groups, and days of exclusive nutritional support (ENS) [short-term (≤ 6 days) vs. longer-term (≥ 7 days)]. Only the first 6 days of ENS was evaluated for a fair comparison. Results The prognostic model demonstrated good discrimination [AUC 0.78 (95% CI 0.73–0.82), and a bias-corrected calibration curve suggested fair accuracy. In high-risk patients with short-term ENS (≤ 6 days), each 10% increase in goal energy and protein intake was associated with an increased adjusted odds (95% CI) of 28-day mortality [1.60 (1.19–2.15) and 1.47 (1.12–1.86), respectively]. In contrast, each 10% increase in goal protein intake during the first 6 days of ENS in high-risk patients with longer-term ENS (≥ 7 days) was associated with a lower adjusted odds of 28-day mortality [0.75 (0.57–0.99)]. Despite the opposing associations, the mean predicted mortality risks and prevalence of malnutrition between short- and longer-term ENS patients were similar. Conclusions Combining baseline nutritional status and disease severity in a prognostic model could accurately predict 28-day mortality. However, the association between the dose of nutrition support during the first 6 days of ENS and 28-day mortality was independent of baseline disease severity and nutritional status. Electronic supplementary material The online version of this article (10.1186/s13054-019-2500-z) contains supplementary material, which is available to authorized users.

BackgroundThe timing and dose of exclusive nutrition support (ENS) have not been investigated in previous studies aimed at validating the modified Nutrition Risk in Critically Ill (mNUTRIC) score. We therefore evaluated the mNUTRIC score by determining the association between dose of nutrition support and 28-day mortality in high-risk patients who received short- and longer-term ENS (≤ 6 days vs. ≥ 7 days).MethodsA prospective cohort study included data from 252 adult patients with > 48 h of mechanical ventilation in a tertiary care institution in Singapore. The dose of nutrition support (amount received ÷ goal: expressed in percentage) was calculated for a maximum of 14 days. Associations between the dose of energy (and protein) intake and 28-day mortality were evaluated with multivariable Cox regressions. Since patients have different durations of ENS, only the first 6 days of ENS in patients with short- and longer-term ENS were assessed in the Cox regressions to ensure a valid comparison of the associations between energy (and protein) intake and 28-day mortality.ResultsIn high-risk patients with short-term ENS (n = 106), each 10% increase in goal energy intake was associated with an increased hazard of 28-day mortality [adj-HR 1.37 (95% CI 1.17, 1.61)], and this was also observed for protein intake [adj-HR 1.31 (95% CI 1.10, 1.56)]. In contrast, each 10% increase in goal protein intake in high-risk patients with longer-term ENS (n = 146) was associated with a lower hazard of 28-day mortality [adj-HR 0.78 (95% CI 0.66, 0.93)]. The mean mNUTRIC scores in these two groups of patients were similar.ConclusionWhen timing and dose of nutrition support were examined, the mNUTRIC did not differentiate high-risk patients who would derive the most benefit from nutrition support.Electronic supplementary materialThe online version of this article (10.1186/s13613-018-0443-1) contains supplementary material, which is available to authorized users.

There is limited evidence for the association between malnutrition and hospital mortality