Late Breaking Abstract - Blood eosinophil count and exacerbation history in COPD: pooled analysis of 24,103 patients

Background: Blood eosinophil counts can help guide physicians treating patients with COPD and a history of exacerbations, and predict patients’ response to ICS treatment. However, studies of eosinophil count as a predictor of future exacerbation risk are inconsistent. In a large patient dataset, we investigated whether blood eosinophil counts can be used as a biomarker for exacerbation rate. Methods: We pooled baseline eosinophil count data for patients with COPD in 16 studies from the tiotropium, olodaterol and tiotropium/olodaterol clinical trial programmes and the WISDOM ICS withdrawal study. Results: Overall, 24,103 patients had eosinophil data available. Median baseline eosinophil count was 170 cells/µL, 20% of patients had an eosinophil count >300 cells/µL and 46% had ≤150 cells/µL (Figure). Distribution of eosinophil counts was similar in patients with ≤1 exacerbation in the previous year (20% >300 cells/µL and 46% ≤150 cells/µL) and in patients with ≥2 exacerbations (21% >300 cells/µL and 46% ≤150 cells/µL), and it was not influenced by ICS use at baseline. The percentages of patients with >300 eosinophils/µL and ≥2 exacerbations were between 4% (without ICS at baseline) and 6% (with ICS at baseline). Conclusions: Although guidelines use blood eosinophil count to identify ICS-responsive patients, we did not find evidence that the blood eosinophil count showed a relationship with exacerbation history.