Use of blood eosinophil count to predict inhaled steroid responsiveness in patients with COPD using primary care health records

Date of Approval
Application Number
Technical Summary

This study will use a new user cohort design to assess outcomes for a group of COPD patients who have not previously been prescribed an inhaled corticosteroid (ICS-naive) and who then commence treatment with a new inhaled maintenance treatment (the index date). The descriptive component of the study will examine records of routine blood eosinophil testing in general practice and their values prior to starting a new inhaled maintenance treatment, their relationship to other baseline variables, and their stability over time. The hypothesis-testing component will test whether baseline blood eosinophil values predict disease outcomes, and outcomes under treatment (ICS responsiveness). The primary outcome will be acute exacerbations of COPD. Patients will be divided into two groups based on whether the new inhaled maintenance medication is an ICS or long-acting bronchodilator. Disease outcomes over time will be compared between those patients starting treatment with ICS and those starting treatment with a long-acting bronchodilator, with adjustment for baseline characteristics, and this will be stratified by baseline blood eosinophil values to determine whether this modifies effectiveness of treatment.

Health Outcomes to be Measured

Primary outcome: exacerbations of COPD (time-to-first exacerbation, as well as sensitivity analyses on number/year, and 2 exacerbations/year) Secondary related outcomes - Pneumonia, death (ONS), hospitalisation (HES), rate of decline in % predicted FEV1 per year.


Helen Ashdown - Chief Investigator - University of Oxford
Helen Ashdown - Corresponding Applicant - University of Oxford
Christopher Butler - Collaborator - University of Oxford
Emily McFadden - Collaborator - University of Oxford
Ian Pavord - Collaborator - University of Oxford
Margaret Smith - Collaborator - University of Oxford
Mike Thomas - Collaborator - University of Southampton
Mona Bafadhel - Collaborator - University of Oxford


HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation