The Relationship Between Prognostic Nutritional Index and All-Cause Mortality in Critically Ill Patients: A Retrospective Study

Abstract

Purpose

The effectiveness and prognostic value of the prognostic nutritional index (PNI) in critically ill patients are unknown. Hence, this study aimed to analyze the relationship between the PNI and all-cause mortality in critically ill patients.

Patients and Methods

Patient data were obtained from the Multiparameter Intelligent Monitoring in Intensive Care III database. The relationship between the PNI and in-hospital mortality was analyzed using receiver operating characteristic curve analysis and a logistic regression model. Propensity score matching (PSM) was used to eliminate the bias caused by confounding factors. The Kaplan–Meier curve and Cox regression model were used to test the effect of the PNI on 30-, 90-, 180-, and 365-day mortality.

Results

A low PNI score is an independent risk factor for in-hospital mortality in critically ill patients. A total of 3644 cases were successfully matched using PSM. The PSM group with balanced covariates obtained similar results in the three models, which were statistically significant. The Kaplan–Meier curve and Cox regression model showed that the PNI was negatively correlated with 30-, 90-, 180-, and 365-day all-cause mortality.

Conclusion

The PNI score is an independent risk factor for all-cause mortality in critically ill patients, where a low PNI score is associated with increased mortality.

Keywords:

• prognostic nutritional index
• mortality
• critically ill patients
• propensity score matching

Abbreviations

BMI, body mass index; CI, confidence interval; HR, hazard ratio; ICU, intensive care unit; MIMIC-III, Medical Information Mart for Intensive Care III database; OASIS, Oxford Acute Severity of Illness Score; OR, odds ratio; PNI, prognostic nutritional index; PSM, propensity score matching; ROC, receiver operating characteristic; SAPS II, Simplified Acute Physiology Score II; SIRS, systemic inflammatory response syndrome; SOFA, Sequential Organ Failure Assessment; WBC, white blood cell.

Data Sharing Statement

The datasets supporting the conclusions of this article are included in the MIMIC-III database (https://mimic.physionet.org/).

Ethics Approval and Consent to Participate

According to the data usage agreement, author Yan Lu (certification number: 35953547) is authorized to obtain detailed information, including information on patient care and treatment, from the database without the need for additional ethical review or approval.

Author Contributions

All authors made substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; took part in drafting the article or revising it critically for important intellectual content; agreed to submit to the current journal; gave final approval of the version to be published; and agree to be accountable for all aspects of the work.

Disclosure

The authors declare that they have no competing interests.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.