Abstract
Rationale. In the general population, increased peripheral blood eosinophil (Eos) levels appears to be associated with increased risk of severe exacerbations among COPD patients. Whether the utility of blood eosinophils as a biomarkers at clinical levels is largely unknown.
Aim. To evaluate the association between Eos and severe exacerbations and mortality in COPD attending pulmonary clinics.
Methods. We recruited from December 1, 2011 to March 30, 2014, smokers (> 20 pack/year) with clinical COPD defined as FEV1/FVC < 0.70 (n=303). Exclusion criteria at entry included the coexistence of other pulmonary, immune, allergic or hematologic disease. All patients had annual examination at the pulmonary clinic including determination of blood eosinophils. Emergency room visit or hospitalization due to COPD exacerbation and mortality were update at January 2016.Eos were dichotomized as < or ≥ 200, 300 and 400 cells per µl.
Results. Baseline characteristics were: FEV1 1.67 l (SD 0.64), FEV1 % predicted 62.2% (19.1), age 71 (8.6); 81.5% male. During a follow-up of 3.8 years (median: 0.3-5.1), there was 71 deaths and 373 COPD exacerbation. The mean (± sd) Eos at enrollment was 188 (± 145) cells per µl. At all visits, 91 patients had Eos < 200 cells per µl, 87 had 200 to 400 cell per µl, 38 had > 400 cells per µl and 87 had variable counts. Using Cox regression models adjusted by age, sex, FEV1% predicted and comorbid conditions, neither baseline Eos nor any Eos cut-of were related to progressive loss of lung function, median annual exacerbation frequency or mortality.
Conclusions. Peripheral blood eosinophils levels are not associated with robust outcomes among COPD patients.
- Copyright ©the authors 2016
