Prognostic value of admission Neutrophil to lymphocyte ratio in patients with acute exacerbation of chronic obstructive pulmonary disease

Abstract

Background: The acute exacerbations of COPD (AECOPDs) are one of the main causes of hospitalization, morbidity, and mortality in the adult population. There are not many tools available to predict the clinical course of these patients during exacerbations.

Aim: This study was designed to estimate the clinical utility of neutrophil/lymphocyte ratio (NLR) as in-hospital prognostic factors in patients with AECOPD.

Materials and Methods: A prospective cohort study was conducted in patients who consulted Tishreen University Hospital in Lattakia for AECOPD and who required hospitalization between April 2020 and April 2021.

NLR was calculated from the admission day complete blood count. Outcomes were in-hospital mortality, intensive care unit (ICU) admission, and the need for invasive mechanical ventilation.

Results: A total of 150 patients with a mean age of 68.5 years were included; 20% were admitted to the ICU, 13.3% needed invasive mechanical ventilation and 14.7% died in the hospital.

NLR > 6 significantly associated with the risk of in-hospital dying (Hazard Ratio [HR]: 4.22), being admitted to the ICU (HR: 2.57), and being mechanically ventilated (HR: 3.64). 

The area under the receiver operating characteristic curve (AUC) of the NLR for predicting in-hospital mortality rate was 0.811. Using 7.9 as the critical NLR value, the sensitivity was 63.6%, and the specificity was 71.1%.

The AUC of the NLR for predicting the frequency of ICU admission was 0.69. Using 7.4 as the critical NLR value, the sensitivity was 64%, and the specificity was 67%. The AUC of the NLR for predicting the frequency of the need for invasive mechanical ventilation was 0.7. Using 8.2 as the critical NLR value, the sensitivity was 63%, and the specificity was 70%.

Conclusion: In patients with AECOPD, NLR > 6 significantly associated with the risk of in-hospital bad outcomes. AECOPD patients with NLR ≥ 7.9 had higher in-hospital mortality rate, patients with NLR ≥ 7.4 were more likely to be admitted to ICU, while those with an NLR ≥ 8.2 were more likely to need invasive mechanical ventilation.