Stability of blood eosinophils over time in patients with asthma

Abstract

Introduction: Blood eosinophils counts (BEC) are an important biomarker in asthma to predict risk of exacerbations and therapeutic response to biologics. Levels might fluctuate over time and are reduced by use of systemic steroids. There are few long-term and real-life data on intra-individual BEC in patients with asthma.

Aims: To assess stability of BEC over time in patients with asthma.

Methods: Multi-national, multidatabase retrospective cohort study using electronic primary care data, collected during 2008-2017, from 4 European countries: IPCI-NL, Aarhus-DK, CPRD-UK and SIDIAP-Spain. In adult patients with asthma, all data on BEC during study period were extracted. BEC while on concomitant use of systemic steroids were excluded from analysis. Generalized Linear models were fitted to log-transformed BEC to estimate the between- and within-patient variance and calculate the intra-class correlation coefficient (ICC).

Results: 660,185 patients with asthma were identified of whom 394,683 (60%) had at least one BEC during study period. The ICC was comparable between databases and the differences between the different models were small. Adjusted ICC ranged between 0.62 (Aarhus) and 0.67 (CPRD). These ICC suggest reasonable stability over time.

Conclusion: BEC were reasonably stable in adult asthma patients in primary care. GSK (PRJ2756)