Blood eosinophil count and exacerbation risk in patients with COPD Marjan Kerkhof, Samatha Sonnappa, Dirkje S. Postma, Guy Brusselle, Alvar Agustí, Antonio Anzueto, Rupert Jones, Alberto Papi, Ian Pavord, Emilio Pizzichini, Todor Popov, Nicolas Roche, Dermot Ryan, Mike Thomas, Claus Vogelmeier, Alison Chisholm, Daryl Freeman, Mona Bafadhel, Elizabeth V. Hillyer, David B. Price

Introduction COPD exacerbations contribute to worsening lung function, impaired quality of life, emergency healthcare use and COPD-related mortality Previous studies have demonstrated an association between high blood eosinophil counts and greater risk of COPD exacerbations However, potential heterogeneity of the association has not yet been explored COPD: chronic obstructive pulmonary disease Vedel-Krogh S, et al. Am J Respir Crit Care Med 2016: 193(9): 965-974

Objective To investigate the association between blood eosinophil counts in stable COPD and exacerbations in the following year in real-life patients, and assess whether the relationship differs significantly in specific patient subgroups Kerkhof M, Price D, et al. Eur Respir J 2017; 50: 1700761 COPD: chronic obstructive pulmonary disease

One year baseline period One year outcome period Study Design Index date: date of the most recent blood eosinophil count with no exacerbation in the preceding 4 weeks n=8318 Study data was extracted from medical records in the Optimum Patient Care Research Database (OPCRD). At the time of data extraction, it contained data from >400 UK primary care practices. One year baseline period One year outcome period Inclusion criteria: Aged ≥40 years COPD-diagnosis without asthma diagnostic Read code ever recorded ≥1 eosinophil counts taken at stable COPD FEV1/FVC <0.70 recorded within 5 years History of smoking Outcome: Number of COPD exacerbations FEV1: forced expiratory volume-one second; FVC: forced vital capacity; COPD: chronic obstructive pulmonary disease Kerkhof M, Price D, et al. Eur Respir J 2017; 50: 1700761

Distribution of Blood Eosinophil Counts in Study Population A higher percentage of men than women have elevated eosinophil counts, consistent with that of the Copenhagen study1 5 1. Vedel-Krogh S, et al. Am J Respir Crit Care Med 2016; 193: 965–974; 2. Kerkhof M, Price D, et al. Eur Respir J 2017; 50: 1700761

Effect of Smoking Status and Blood Eosinophil Count on COPD Exacerbations 6 CI: confidence interval; COPD: chronic obstructive pulmonary disease Kerkhof M, Price D, et al. Eur Respir J 2017; 50: 1700761

Evaluation of Blood Eosinophil Cut-Points Adjusted rate ratios (RRs; [95% CI]) of COPD exacerbations for ex-smoking patients at different cut-points used to define elevated blood eosinophil counts. CI: confidence interval; COPD: chronic obstructive pulmonary disease Kerkhof M, Price D, et al. Eur Respir J 2017; 50: 1700761

Association Between Blood Eosinophil Count and Exacerbations Increased exacerbation rate with elevated eosinophil count was restricted to ex- smokers The association was found in men [RR=1.21 (1.06-1.38)] only and not in women [RR=0.98 (0.80-1.21)], but this difference in association was not significant when statistically tested (p=0.11) The association was also found in patients treated with ICS [RR=1.17 (1.02-1.35)] No significant association between a low eosinophil count <0.05 x 109/L (3.4%) and COPD exacerbations [RR=1.06 (0.89-1.27)] COPD: chronic obstructive pulmonary disease; ICS: inhaled corticosteroids Kerkhof M, Price D, et al. Eur Respir J 2017; 50: 1700761

Conclusions Elevated blood eosinophil counts may predict COPD exacerbation risk only in ex- smokers This analytical strategy may eventually help in the targeting of therapy to specific patient subgroups to maximise benefit and minimise risk for individual patients COPD: chronic obstructive pulmonary disease Kerkhof M, Price D, et al. Eur Respir J 2017; 50: 1700761

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