Peripheral Blood Eosinophils and Nine Years Mortality in COPD Patients

Abstract

Background Eosinophil counts increase during chronic obstructive pulmonary disease (COPD) exacerbation and influence the response to different agents (such as inhaled and systemic corticosteroids), as well as increase the production of other inflammatory cytokines. However, few studies have evaluated the association between peripheral blood eosinophils with mortality rate. Objective To evaluate the association between peripheral blood eosinophils and mortality rate in COPD patients over a nine-year period. Study Design and Methods This cohort included 133 COPD patients assessed at baseline by spirometry, pulse oximetry (SpO 2 ), complete blood count, body composition, dyspnea intensity [Modified Medical Research Council (mMRC)] and the six-minute distance test (6MWD). The Kaplan–Meier curve followed by a Log rank test was used to evaluate mortality rate related to eosinophil cutoff point categorization. Multivariate Cox regression analysis was performed to identify the association between eosinophils and mortality with all subjects evaluated at baseline, adjusted for age, gender, mMRC, 6MWT, forced expiratory volume in the first second (FEV 1 ) and SpO 2 . Results Nineteen patients did not complete follow-up and it was not possible to identify the date of death in four others. Therefore, 110 patients were included in the analysis. At baseline, 81% presented ≥150 eosinophil cells and 72% presented ≥2%. We identified a three-fold higher risk of death in those with <2% eosinophils and <150 cells. We did not identify statistical differences when using other cutoff points. Conclusion The decrease in number of peripheral eosinophils, with cutoff points at 2% and 150 cells, may be associated with a higher risk of death in COPD patients over nine years.

Nine-Year Follow-Up of Interleukin 6 in Chronic Obstructive Pulmonary Disease – Complementary Results from Previous Studies

“…Demographic and clinical characteristics of the involved patients in the survival analysis, and the evolution of other markers at baseline, after three and nine years can be consulted in a previous publication and in Supplemental Material . 22 , 24 ⁠…”

“…The applied methodology was the same used in this previous study, where further details can be found. 22 , 24 ⁠…”

“…These assessments were reapplied to survivors after three and nine years and more details are available in previous studies. 18 , 19 , 22 , 24 ⁠…”

“…These assessments were reapplied to survivors after three and nine years and more details are available in previous studies. 18,19,22,24 routinely used by the Technical Section of Botucatu School of Medicine Laboratory and Clinical Analysis.…”

“…2,16 Furthermore, we did not find many data from nearly a decade of follow-up related to IL-6 in Brazilian COPD patient. 10,[17][18][19][20][21][22][23][24] In this sense, better understanding the role of IL-6 over time, helps in a more effective search for inflammation control and, consequently, minimizes its related outcomes, such as reduced physical capacity, greater occurrence of exacerbations and increased mortality. [9][10][11][12] Thus, our hypothesis is that IL-6 is associated to COPD mortality over nine years of follow-up and the objective of our study was to assess the association of IL-6 in mortality risk in patients with COPD over nine years, as well as verify the variation of IL-6 in survivals over nine years.…”