Nutritional risk factors for all-cause mortality of critically ill patients: a retrospective cohort study

Abstract

Objectives: This study aimed to explore the predictive value of single and multiple risk factors for the clinical outcomes of critically ill patients receiving enteral nutrition and to establish an effective evaluation model.

Design: Retrospective cohort study.

Setting: Data from the 2020-2021 period were collected from the electronic records of the First Affiliated Hospital, Nanjing Medical University.

Participants: 459 critically ill patients with enteral nutrition in the geriatric intensive care unit were included in the study.

Primary and secondary outcome measures: The primary outcome was 28-day mortality. The secondary outcomes were 28-day invasive mechanical ventilation time, intensive care unit stay, Nutrition Risk Screening 2002 (NRS2002) score and Acute Physiology and Chronic Health Evaluation II (APACHE II) score.

Results: Independent prognostic factors, including prealbumin/procalcitonin (PCT) ratio and APACHE II score, were identified using a logistic regression model and used in the nomogram. The area under the receiver operating characteristic curve and concordance index indicated that the predictive capacity of the model was 0.753. Moreover, both the prealbumin/PCT ratio and the combination model of PCT, prealbumin and NRS2002 had a higher predictive value for clinical outcomes. Subgroup analysis also identified that a higher inflammatory state (PCT >0.5 ng/mL) and major nutritional risk (NRS2002 >3) led to worse clinical outcomes. In addition, patients on whole protein formulae bore less nutritional risk than those on short peptide formulae.

Conclusions: This nomogram had a good predictive value for 28-day mortality in critically ill patients receiving enteral nutrition. Both the prealbumin/PCT ratio and the combination model (PCT, prealbumin and NRS2002), as composite models of inflammation and nutrition, could better predict the prognosis of critically ill patients.

Keywords: Adult intensive & critical care; INTENSIVE & CRITICAL CARE; NUTRITION & DIETETICS; Nutritional support.

Figure 1

Patient records enrolment flow chart. ICU, intensive care unit.

Figure 2

Nomogram to calculate risk score and predict 28-day mortality. Scores were assigned for APACHE II and PA/PCT by drawing a line upward from the corresponding values to the ‘points’ line. The sum of all these scores, plotted on the ‘total points’ line, corresponds to predictions of 28-day mortality risk in critically ill patients. APACHE II, Acute Physiology and Chronic Health Evaluation II; PA, prealbumin; PCT, procalcitonin.

Figure 3

Performance evaluation of the nomogram in the primary cohort. (A) Receiver operating characteristic curve analysis; (B) calibration curve analysis; (C) decision curve analysis. N=301. AUC, area under the curve.

Figure 4

Receiver operator characteristic (ROC) curves for single and composite indicators in predicting 28-day outcome. (A) ROCs for single indicators; (B) ROCs for PCT-based composite indicators; (C) ROCs for NRS2002-based composite indicators; (D) ROCs for PA-based composite indicators. N=301. APACHE II, Acute Physiology and Chronic Health Evaluation II; AST, aspartate aminotransferase; Crea, serum creatinine; NRS2002, Nutrition Risk Screening 2002; PA, prealbumin; PCT, procalcitonin; TRF, transferrin.

Figure 5

Survival curves for critically ill patients with enteral nutrition. (A) Survival curves for groups divided by conventional values of NRS2002 and PCT; (B) survival curves for groups divided by cut-off values of NRS2002 and PCT. N=301. *P<0.05, **p<0.01. NRS2002, Nutrition Risk Screening 2002; PCT, procalcitonin.

Figure 6

Improvement of critically ill patients with different nutritional formulae. (A) Improvement of AST after 3 days of enteral nutrition; (B) improvement of ALT after 3 days of enteral nutrition; (C) improvement of NRS2002 after 7 days of enteral nutrition. N=301. *P<0.05, **p<0.01. ALT, alanine aminotransferase; AST, aspartate aminotransferase; NRS2002, Nutrition Risk Screening 2002; PB, peptide-based formulae; PW, peptide step to whole protein formulae; WP, whole protein formulae.

Figure 7

Severity scores, nutrition status and inflammatory markers in different nutrition formulae groups. (A) APACHE II score in different groups; (B) NRS2002 score in different groups; (C) globulin in different groups; (D) Crea in different groups; (E) ALT in different groups; (F) AST in different groups. N=301. *P<0.05, **p<0.01. ALT, alanine aminotransferase; APACHE II, Acute Physiology and Chronic Health Evaluation II; AST, aspartate aminotransferase; Crea, serum creatinine; NRS2002, Nutrition Risk Screening 2002; PB, peptide-based formulae; PW, peptide step to whole protein formulae; WP, whole protein formulae.