Introduction: The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2019
recommends the use of absolute blood eosinophil count as a guide for the escalation and de-escalation
of inhaled corticosteroids (ICS) in the pharmacological management of patients with chronic obstructive
pulmonary disease (COPD). We evaluated the risk of moderate or severe exacerbations among
patients escalating and de-escalating ICS therapy by absolute blood eosinophil thresholds in this systematic
Methods: Through a comprehensive literature search of PubMed, EMBASE, MEDLINE and clinical
trial sites up to April 2019, we identified relevant studies. We used generic inverse variance with fixed
estimates to compare the risk of moderate or severe exacerbations among COPD patients with elevated
blood eosinophil counts exposed to inhaled corticosteroids (ICS) versus non-ICS treatments groups
expressed as risk ratios.
Results: Ten studies (8 randomised control trials and 2 observational studies) were included, with a
total of 85,059 COPD patients. In our pooled analysis, we found an overall reduction in risk of moderate
or severe exacerbations in patients with absolute blood eosinophil thresholds ranging from ≥ 100
to ≥ 340 cells/μL among patients escalating ICS (RR, 0.77, 95% CI, 0.73-0.81). For studies evaluating
the effects of de-escalation of ICS on moderate to severe exacerbations using blood eosinophil thresholds
of ≥ 300 to ≥ 340 cells/μ had an increased risk of moderate or severe exacerbations following the
de-escalation of ICS in COPD patients with blood eosinophil (RR, 1.66, 95% CI, 1.31-2.10).
Conclusion: This study confirms the validity of the recommended absolute blood eosinophil count
thresholds for the escalation and de-escalation of ICS among COPD patients. However, this recommendation
is for COPD patients with prior exacerbations rather than among newly diagnosed COPD
patients as observed in this study.