Asthma is a common chronic respiratory disease, with patients presenting symptoms such as coughing, shortness of breath and wheezing. About ten percent of the asthma population have severe form of the disease, leading to increased hospitalizations and treatments with steroids and antibiotics. The severe asthma population constitute two sub-groups based on the eosinophil counts; severe eosinophilic (patients with high blood eosinophils) and patients with low eosinophil counts. While, current treatments have improved asthma control, the disease burden remains high, especially in those patients with low blood eosinophil counts. Therefore, this study will use healthcare records to describe patients with asthma and low blood eosinophil counts in order to understand the disease burden and their association with adverse clinical outcomes and death. This will further highlight the need for providing improved care and better management of the disease in these patients.
Severe asthma requires a high dose of Inhaled corticosteroids to prevent it from becoming uncontrolled, and in some patients the disease may remain uncontrolled despite this treatment. While, biologic therapies approved for severe asthma have shown increased asthma control, the response has been greater among patients with eosinophilic asthma and limited and/or inconsistent efficacy among those with low blood eosinophil counts (BEC <300 cells/μL). This descriptive study aims to understand the burden of disease including asthma-related exacerbations, asthma control, healthcare resource use and treatment patterns in severe asthma patients with low blood eosinophil counts. The study will utilize CPRD Aurum linked to Hospital Episode Statistics (HES) databases to estimate disease burden in primary and secondary care. The burden of severe asthma in this population is also evaluated in tertiary care settings using UK Severe Asthma Registry (UKSAR). However, there will be no patient linkage and no comparative analyses conducted between CPRD Aurum and UKSAR. The study period will begin from 1st October 2010- 31st October 2020 (depending on latest available linked dataset). Each of clinical outcomes of interest will be described separately and relative risks of risk factors associated with increased exacerbations and uncontrolled asthma will be estimated using negative binomial regression models or logistic models where appropriate. In addition, healthcare resource use will be described through General Practice (GP) consultations and hospital admissions, and the resulting direct costs will be estimated. This evidence will be used to highlight unmet treatment needs and quantify the burden of illness in severe asthma patients with low blood eosinophilic counts.
The study outcomes are aligned to the core objectives of this study and described below.
Primary outcomes include specific Asthma-specific treatments; Asthma- specific hospitalizations; Admission to Accident & Emergency; Asthma-related and All-cause mortality; Acute respiratory events; Prescription and use of Oral corticosteroids
Secondary outcomes include monetized costs of health care resource use; resources include disease management services in the clinical guideline, e.g., GP consultations, medications and hospitalizations. Others include urgent care visits, emergency department attendances etc.
Ruiqi Zhang - Chief Investigator - AstraZeneca Ltd - UK Headquarters
Ruiqi Zhang - Corresponding Applicant - AstraZeneca Ltd - UK Headquarters
Jessica Gordon - Collaborator - AstraZeneca Ltd - UK Headquarters
John Busby - Collaborator - Queen's University Belfast
Liam Heaney - Collaborator - Queen's University Belfast
Ruiqi Zhang - Collaborator - AstraZeneca Ltd - UK Headquarters
Tamsin Morris - Collaborator - AstraZeneca Ltd - UK Headquarters
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Patient Level Index of Multiple Deprivation