Evaluation of exacerbations and blood eosinophils in UK and US COPD populations

Abstract

Background Blood eosinophil counts and history of exacerbations have been proposed as predictors of patients with chronic obstructive pulmonary disease (COPD) who may benefit from triple therapy (inhaled corticosteroid, long-acting β 2 -agonist and long-acting muscarinic antagonist). Methods In a retrospective cohort analysis we examined the profiles of COPD patients from the UK Clinical Practice Research Datalink (CPRD) and US Optum Clinformatics™ Data Mart (Optum) databases with reference to exacerbation frequency and blood eosinophil distribution. Results Of the 31,437 (CPRD) and 383,825 (Optum) patients with COPD, 15,364 (CPRD) and 139,465 (Optum) met the eligibility criteria and were included. Among patients with ≥2 exacerbations and available eosinophil counts in the baseline period (CPRD, n = 3089 and Optum, n = 13414), 17.0 and 13.3% respectively had eosinophil counts ≥400 cells/μL. Patients with ≥2 exacerbations or eosinophil count ≥400 cells/μL during first year, exacerbated at least once (CPRD, 82.8% vs Optum, 80.6%) or continued to have eosinophil count ≥300 cells/μL (76.8% vs 76.5%), respectively in the follow-up year. In both years, a higher variability in the number of exacerbations and eosinophil count was observed in patients with one exacerbation and eosinophil counts between 300 and 400 cells/μL; patients with eosinophil count < 150 cells/μL had the lowest variability. Approximately 10% patients had both ≥2 exacerbations and eosinophil count ≥300 cells/μL across the databases. Conclusion A high variability in blood eosinophil counts over two consecutive years was observed in UK and US patients with COPD and should be considered while making treatment decisions. A small proportion of COPD patients had frequent exacerbations and eosinophil count ≥300 cells/μL. Electronic supplementary material The online version of this article (10.1186/s12931-019-1130-y) contains supplementary material, which is available to authorized users.

Impact of baseline symptoms and health status on COPD exacerbations in the FLAME study

“…This may be due to the smaller number of patients in higher blood eosinophil group, as well as the potential effect of the two treatment arms [21,22,35]. We did not observe any association between smoking status (current and ex-smokers) and the efficacy of the two treatments on the risk of exacerbations [20,35]. Despite the evidence supporting reduced steroid responsiveness in current smokers with asthma, the efficacy of ICS in current smokers with COPD is still rather controversial.…”

“…Unlike previous reports, our results did not show any impact of blood eosinophil on the future risks of exacerbations. This may be due to the smaller number of patients in higher blood eosinophil group, as well as the potential effect of the two treatment arms [21,22,35]. We did not observe any association between smoking status (current and ex-smokers) and the efficacy of the two treatments on the risk of exacerbations [20,35].…”

Prevalence and Baseline Clinical Characteristics of Eosinophilic Chronic Obstructive Pulmonary Disease: A Meta-Analysis and Systematic Review

“…Significant variability in blood eosinophil levels has been shown throughout the course of COPD (38,39). To investigate the stability of blood eosinophilic inflammation (≥2%), subjects were classified into predominantly (PE), intermittently (IE), and rarely (RE) eosinophilic groups in one study (40).…”

COPD treatment choices based on blood eosinophils: are we there yet?

“…What perhaps is more surprising is that eosinophilia, which is typically associated with asthma, occurs in a subset of patients with COPD. In a recent study of patient data from general practice in both the UK and USA (around 43 000 patients), eosinophilia was evident in 31% and 25% of the UK and USA cohorts of stable COPD patients, respectively [9], and some studies have reported eosinophilia in up to 40% of patients with COPD [10]. However, COPD studies from the 1990s, often with small numbers of patients, had negative outcomes when looking at the effect of corticosteroid treatment on eosinophilic inflammation [11].…”