Background/aim: The neutrophil to lymphocyte ratio (NLR) is an inflammatory biomarker that
could be used as an indicator of systemic inflammation (sepsis) and could also be used to predict
the prognosis of some diseases such as solid cancer, community pneumonia, as well as
cardiovascular outcomes. The purpose of this study was to assess the potential role of NLR in
patients with acute exacerbation of COPD (AECOPD) compared to those in the stable phase of
the disease.
Methods: NLR was assessed and compared in patients with AECOPD (n=92) and those in the
stable phase of COPD (n=240). Patients under the age of 18 were excluded from the study,
patients who used inhaled corticosteroids, an those with any condition affecting the NEU or
LYM count in peripheral blood (hematological illnesses, pregnancy, or a history of medication
use). The NLR was determined using NEU and LYM counts from regular blood tests.
Results: We included 332 inpatients with COPD diagnosed in our hospital from April to October
2021. Patients with exacerbation had considerably lower levels of FEV1/FVC (55.38±9.14 vs
60.54±6.95), and NLR ratio.
Conclusion: We found that the NLR ratio was lower in patients with AECOPD.

Keywords: NLR, COPD, ratio, acute exacerbation