Eosinophilic granulomatosis with polyangiitis (EGPA), formerly known as “Churg-Strauss syndrome,” is an inflammatory disease of small and medium sized blood vessels. People with EGPA often have their lungs and skin affected by the disease, but other organs such as the heart, kidneys, nerves and bowels are also affected by the disease. Eosinophils are a type of white blood cell that usually fights infections and is related to allergies. People with EGPA often have high levels of EGPA in blood tests and in affected body parts. The prevalence of EGPA has been reported to range from 10.7 to 14 cases per million people in European populations, and the annual incidence ranges from 0.5 to 4.2 cases per million. Incidence and prevalence estimates vary by country, population, time period, and diagnostic criteria. Given the rarity of EGPA, limited data exist on the burden of illness in the United Kingdom (UK) population. Results from a United States (US) study reported that EGPA patients treated with oral corticosteroids experienced high burden and healthcare use despite already being on standard treatment. The proposed study will describe the prevalence, incidence, patient characteristics, and healthcare use among EGPA patients in order to describe EGPA burden and identify potential areas of unmet need.
The primary objectives are to estimate the prevalence of EGPA for each calendar year between 2005 and 2019 inclusive and to estimate the annual incidence rate of EGPA between 2006 and 2019 inclusive. The secondary objectives are to describe demographics at time of first recorded EGPA diagnosis (index) and clinical characteristics in the 12 months prior to the index date (baseline), and to describe health care resource use, including the number of hospitalizations, Accident & Emergency (A&E) visits, outpatient visits, procedures undertaken, and imaging tests among EGPA patients during the 12 months following index date. CPRD-AURUM will be used to find patients diagnosed with EGPA (the numerator). The denominator for the prevalence of EGPA will be patients registered within CPRD-AURUM within the respective calendar year. The denominator for EGPA incidence will be patients with at least 365 days after the first registration in the prior to contributing to time at risk.
Linkage of CPRD-AURUM with Hospital Episode Statistics (HES)-Admitted Patient Care will be used to obtain healthcare use for EGPA-, any-cause hospitalizations, length of stay, and any procedures. The HES Accident & Emergency data file will be used to obtain any-cause accident and emergency visits. The HES Outpatient data file will be used to obtain any-cause outpatient visits. The HES Diagnostic Imaging Dataset will be used to obtain imaging tests. Primary care visits will be determined using CPRD-AURUM.
Prevalence and incidence will be reported as a rate per 1,000,000 persons and 1,000,000 person-years, respectively. All healthcare utilization will be reported using distributions, proportions, mean, median, and range.
Primary outcomes: prevalence; incidence.
Secondary outcomes: EGPA-specific hospitalizations; EGPA-specific hospitalization length of stay; any-cause hospitalizations; any-cause hospitalization length of stay; any procedures undertaken; any imaging tests; any outpatient visits; specialty seen in outpatient visits; any primary care visit with a general practitioner; any primary care visit with a nurse; any primary care visit with an allied health professional; any oral corticosteroid use.
Rupert Jakes - Chief Investigator - GlaxoSmithKline - UK
Jeremiah Hwee - Corresponding Applicant - GlaxoSmithKline Research & Development Limited (UK)
George Mu - Collaborator - GlaxoSmithKline Research & Development Limited (UK)
Krishnarajah Nirantharakumar - Collaborator - University of Birmingham
lorraine harper - Collaborator - University of Birmingham
Qinggong Fu - Collaborator - GlaxoSmithKline Research & Development Limited (UK)
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient