The Relationship Between Prognostic Nutritional Indexes and the Clinical Outcomes of Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Abstract

Purpose

Nutritional status is related to the clinical outcomes of patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). The aim of this study was to investigate the association between nutritional status, measured by the prognostic nutritional index (PNI), and adverse hospitalization outcomes in patients with AECOPD.

Methods

Consecutive AECOPD patients admitted to the First Affiliated Hospital of Sun Yat-sen University between January 1, 2015 to October 31, 2021 were enrolled. We collected the clinical characteristics and laboratory data of patients. Multivariable logistic regression models were developed to assess the relationship between the baseline PNI and adverse hospitalization outcomes. A generalized additive model (GAM) was used to identify any non-linear relationship. In addition, we performed a subgroup analysis to tested the robustness of the results.

Results

A total of 385 AECOPD patients were involved in this retrospective cohort study. Based on the tertiles of PNI, patients in the lower tertiles of PNI showed more worse outcome incidence (30 [23.6%] versus 17 [13.2%] versus 8 [6.2%]; p < 0.001). Multivariable logistic regression analysis revealed that the PNI were independently associated with adverse hospitalization outcomes after adjustment for confounding factors (Odds ratio [OR] = 0.94, 95% CI: 0.91 to 0.97, P < 0.0001). After adjusting for confounders, smooth curve fitting showed a saturation effect, suggesting that the relationship between the PNI and adverse hospitalization outcomes was nonlinear. Two-piecewise linear regression model suggested that the incidence of adverse hospitalization outcomes significantly decreased with PNI level up to the inflection point (PNI = 42), and PNI was not associated with adverse hospitalization outcome after that point.

Conclusion

Decreased PNI levels at admission were determined to be associated with adverse hospitalization outcomes in patients with AECOPD. The results obtained in this study may potentially assist clinicians optimize risk evaluations and clinical management processes.

Keywords:

• AECOPD
• nutrition
• prognostic nutritional index
• adverse hospitalization outcomes
• non-linearity

Abbreviations

COPD, chronic obstructive pulmonary disease; AECOPD, acute exacerbation of chronic obstructive pulmonary disease; PNI, prognostic nutritional index; BMI, body mass index; DBP, diastole blood pressure; SBP, systolic blood pressure; NT-proBNP, N-terminal probrain natriuretic peptide; aCCI, age-adjusted Charlson Comorbidity Index; Cr, creatinine; BUN, blood urea nitrogen; TP, total protein; TG, triglyceride; TC, total cholesterol; LDL-c, low-density lipoprotein cholesterol; HDL-c, high-density lipoprotein cholesterol; Eos, eosinophils; PLT, platelet; Lym, lymphocyte; Hb, hemoglobin; CRP, C-reactive protein; PCT, procalcitonin; LDH, lactic dehydrogenase; PaCO₂, partial pressure of carbon dioxide in arterial blood; PaO₂, partial pressure of oxygen in arterial blood; ICU, intensive care unit; NIMV, noninvasive mechanical ventilation; MIs, multiple imputations; OR, odd ratios; CI, confidence intervals.

Data Sharing Statement

The dataset used and analyzed during the current study can be accessed by reasonable request from the authors.

Ethics Approval and Informed Consent

This study was approved by the Ethics Review Committee of the First Affiliated Hospital of Sun Yat-sen University in April of 2022 (reference number: [2022]-179). Due to the anonymous nature of the data, an exemption for informed consent was obtained from the Investigational Ethical Review Board.

Acknowledgments

The authors would like to thank all the study participants and the First Affiliated Hospital of Sun Yat-sen University.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors declare that they have no conflicts of interest in this work.

Additional information

Funding

The authors declare that this is a non-funded study.