Abstract Background Blood eosinophil count is increasingly recognised as a biomarker predicting treatment response to inhaled steroids and Th2 targeted biologics in chronic obstructive pulmonary disease (COPD). Acute exacerbations are the major cause of health care utilisation and a significant driver of disease progression in COPD. Approximately one third of patients experience eosinophilic COPD exacerbations. However, little is known about blood eosinophils in exacerbation recovery and the impact on clinical outcomes. Aim The aim of this study was to describe the temporal variation in blood eosinophil counts during COPD exacerbation recovery and the relationship with clinical outcomes. Methods Data was collected from participants in the London COPD exacerbation cohort from 2010 to 2020. Participants documented changes in respiratory symptoms using diary cards. Exacerbation recovery was defined as a return to baseline symptoms for 2 consecutive days. Blood eosinophil counts were measured during disease stability, at exacerbation prior to starting antibiotics or steroids and at 1 week, 2 week and 6 week recovery time points. A blood eosinophil count of ≥ 300 cells/ μl was classified as high. Results There were 1216 reported exacerbations from 268 patients with blood eosinophil counts recorded. A high blood eosinophil count was present in 28.7% of exacerbations at exacerbation onset prior to treatment, 17.2% of exacerbations at the 1 week, 27.6% at 2 weeks and 32.2% of exacerbations at 6 weeks recovery time points. Increasing blood eosinophil counts at 1 week correlated with delayed time to exacerbation recovery (rho 0.449 p = 0.036). Conclusions There were high blood eosinophil counts during exacerbation recovery in approximately a third of COPD patients. A raised blood eosinophil count at 1 week was associated with delayed exacerbation recovery. Persistent eosinophilic inflammation could be a therapeutic target to improve recovery from exacerbations of COPD. Figure 1 Temporal change in blood eosinophil counts during COPD exacerbation recovery This abstract is funded by: None
Finney et al. (Fri,) studied this question.