Prevalence of blood eosinophilia in adults with COPD according to the cut-off point

Abstract

Objective: To determine the prevalence of blood eosinophilia in adults with chronic obstructive pulmonary disease (COPD) according to different cut-off points. Methods: A cross-sectional study was carried out in patients with COPD. The frequency of blood eosinophilia was determined by absolute (cells/ µL) and relative (%) eosinophil count. Multivariate methods were used in order to identify the associated factors. Results: 81 patients were included; the mean age was 71.9 ± 9.8 years; 46 (57%) of the patients were men. The prevalence of eosinophilia for the cut-off points of ≥ 100, ≥ 150, ≥ 200, ≥ 300, and ≥ 400 cells/µL was of 64.2%, 37.0%, 16.1%, and 9.9% respectively. Out of 81 patients, 34 (42%) had a relative eosinophil concentration of ≥ 2%; 21 (25.9%) ≥ 3%; 14 patients (17.3%) had ≥ 4%; and 10 patients (12.3%) had ≥ 5%. Eosinophilia of ≥ 100 cells/µL was associated with age of ≥ 80 years (OR = 6.04, p = 0.026), and with the exacerbation of COPD (OR = 9.40, p = 0.038); in contrast, eosinophilia of ≥ 2% was associated only with age of ≥ 80 years (OR = 3.73, p = 0.020). In addition, the eosinophil count of ≥ 100 and < 300 cells/ µL was associated with the exacerbation of COPD (OR = 11.00, p = 0.026). Conclusions: Our results suggest that the frequency of eosinophilia in the context of COPD shows substantial variations according to the used definition.