Prognostic Value of Neutrophil to Lymphocyte Ratio for Predicting 90-Day Poor Outcomes in Hospitalized Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Abstract

Objective

This study aimed to evaluate the predictive value of neutrophil to lymphocyte ratio (NLR) for poor outcomes within 90-day in hospitalized patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Methods

A retrospective study including 503 AECOPD patients was performed, and the subjects’ clinical characteristics were collected. Binary logistic regression analysis was used to identify risk factors for 90-day poor outcomes in patients with AECOPD. Receiver-operating characteristic curves (ROC) and areas under the curves (AUC) were used to assess the ability of different biomarkers to predict the risk of 90-day mortality, readmission and re-exacerbation in patients with AECOPD.

Results

During the follow-up, 188 patients (38.4%) redeveloped exacerbations, 112 patients (22.9%) were readmitted, and 20 patients (4.1%) died directly resulted from COPD or COPD-related causes. Multivariate analysis demonstrated that age>72 years (OR: 14.817, 95% CI: 1.561–140.647), NLR>14.17 (OR: 9.611, 95% CI: 2.303–40.113), EOS<0.15% (OR: 8.621, 95% CI: 3.465–34.913) and BNP>2840ng/L (OR: 5.291, 95% CI: 1.367–20.474) at discharge were independent risk factors for 90-day mortality in AECOPD patients. NLR was the optimal biomarker for predicting 90-day mortality with an AUC of 0.802 (95% CI: 0.631–0.973). Using 14.17 as the critical value of NLR, the sensitivity was 76.7%, and the specificity was 88.9%. Compared with mortality, NLR had no significant advantage in predicting risk of short-term re-exacerbation (AUC=0.580, 95% CI:0.529–0.632, p=0.001) and readmission (AUC=0.555, 95% CI:0.497–0.614, p=0.045), with AUCs less than 0.6. In contrast, the predictive value of EOS (AUC=0.561, 95% CI:0.502–0.621, p=0.038) was slightly better than NLR in terms of readmission within 90 days. CRP did not serve as a well predictive biomarker for the risk of readmission and re-deterioration (p>0.05).

Conclusion

NLR is of great value in predicting the risk of poor outcomes, especially COPD associated mortality, in hospitalized patients with AECOPD within 90 days after discharge.

Keywords:

• acute exacerbation of chronic obstructive pulmonary disease
• neutrophil to lymphocyte ratio
• mortality
• readmission
• eosinophil count
• C-reactive protein
• biomarker

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

Xiaoyi Feng and Huaye Xiao are co-first authors for this study. The authors report no conflicts of interest in this work.

Additional information

Funding

This work was supported by the National Science Foundation of China (Grants No.31671189) and the Sichuan Science and Technology Agency (Grants No.2018SZ0109).