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