Association Between Blood Eosinophil Level and Exacerbation Risk in Patients with COPD

Date of Approval: 
2016-04-20 00:00:00
Lay Summary: 
Chronic Obstructive Pulmonary Disease (COPD) is a leading cause of illness and death worldwide. Acute flare-ups of COPD, called exacerbations, are one of the main drivers of illness and death related to COPD, and are often due to infection. During an exacerbation a patient may have trouble breathing and may have a cough that is worse than usual. Thus far two studies have found that higher levels of eosinophils, which are a marker of inflammation that can be detected through a blood test, are associated with a higher frequency of COPD exacerbations. This study seeks to expand the limited knowledge on whether patients with higher eosinophil levels are more likely to experience COPD exacerbations. The study will examine blood eosinophil levels of COPD patients and the frequency of COPD exacerbations in the time period following the measurement. Analysis will examine whether patients with higher eosinophil levels experience more frequent COPD exacerbations. Results will help show whether eosinophil levels could potentially be used to help identify patients at risk of COPD exacerbations. If so, it is possible that specific treatments could be offered to patients who might be more likely to experience exacerbations, potentially improving the health of these patients.
Technical Summary: 
The objective is to examine the association between blood eosinophils and subsequent risk for exacerbations in patients with COPD being treated with long-acting and/or short-acting bronchodilators, with or without inhaled corticosteroids (ICS). The design is a retrospective cohort study of patients with COPD as evidenced by a medical code in the CPRD between January 2004 and February 2013. The index date is the date of the first blood eosinophil measurement (study exposure) between January 2010 and February 2013 that follows the COPD medical code and meets the stable state and other inclusion requirements. The 12-month period before the index date will be used to assess demographics, exacerbation and treatment history. The follow up period from index date until censoring date, the earliest of the following events: 1. death, 2. leaving the practice, or 3.end of follow-up on February 28, 2014, will be examined for the occurrence of COPD exacerbations (study outcome). Descriptive analysis will be conducted. A negative binomial model will be used to examine the association between blood eosinophils and exacerbation rate. Stratified analyses based on 1) time-varying ICS use during follow-up and 2) exacerbation history in the 12 months preceding the index date will also be conducted.
Health Outcomes to be Measured: 
COPD exacerbations
Application Number: 
16_058
Collaborators: 

Jeanne Pimenta - Chief Investigator - BioMarin (U.K.) Limited
Sarah Landis - Collaborator - BioMarin (U.K.) Limited
Shibing Yang - Collaborator - GSK

Linkages: 
HES Admitted Patient Care;HES Outpatient;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation