Neutrophil-to-lymphocyte ratio, blood eosinophils and COPD exacerbations: a cohort study

Jens Ellingsen; Christer Janson; Kristina Bröms; Karin Lisspers; Björn Ställberg; Marieann Högman; Andrei Malinovschi

doi:10.1183/23120541.00471-2021

Neutrophil-to-lymphocyte ratio, blood eosinophils and COPD exacerbations: a cohort study

ERJ Open Res. 2021 Dec 27;7(4):00471-2021. doi: 10.1183/23120541.00471-2021. eCollection 2021 Oct.

Authors

Jens Ellingsen¹, Christer Janson¹, Kristina Bröms², Karin Lisspers², Björn Ställberg², Marieann Högman¹, Andrei Malinovschi³

Affiliations

¹ Dept of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden.
² Dept of Public Health and Caring Sciences, Family Medicine and Preventive Medicine, Uppsala University, Uppsala, Sweden.
³ Dept of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden.

Abstract

Background: Blood neutrophil-to-lymphocyte ratio (NLR) and blood eosinophils (B-Eos) are emerging biomarkers in COPD. This study examined whether they could predict acute exacerbations of COPD (AECOPDs), and determined their longitudinal stability.

Methods: In this closed cohort study, Swedish subjects with spirometry-verified COPD attended three yearly visits in a stable phase of the disease. Blood cell counts, spirometry and questionnaire-assessed AECOPD-history (worsening of COPD leading to an unscheduled visit and/or use of antibiotics and/or oral corticosteroids) were collected at each visit.

Results: Of 466 included subjects 57% were female. Baseline mean±sd forced expiratory volume in 1 s was 58±17% predicted. High NLR (≥3.0) was more common in subjects with previous AECOPDs than in those without (33.5% versus 20.4%, p=0.002). In two-level mixed-effects logistic regression models adjusted for confounders, NLR as a continuous variable (OR 1.20, 95% CI 1.04-1.38) and B-Eos ≥300 cells·µL^-1 (OR 1.54, 95% CI 1.06-2.24) were associated with future AECOPDs. In 386 subjects with blood cell data available at all three visits, the intraclass correlation coefficient for NLR was 0.61 (95% CI 0.56-0.66) and for B-Eos 0.69 (95% CI 0.64-0.73). NLR was persistently ≥3.0 in 10.6% and B-Eos was persistently ≥300 cells·µL^-1 in 15.3%.

Conclusions: Stable phase NLR and B-Eos were associated with future AECOPDs. NLR on its own is probably not useful to predict AECOPDs but might be included in a risk scoring index. A minority of subjects with COPD had persistently elevated stable-phase NLR or B-Eos, and the biomarkers showed fair longitudinal reliability.