Approximately one million children in the United Kingdom have asthma, a respiratory condition that is characterised by the narrowing of the airways. Asthma can cause the patient to wheeze, cough and have difficulty breathing. If symptoms are severe, the patient may be admitted to hospital and each year a small number of children die as a result of an asthma attack. The aim of this study is to use data from the Clinical Practice Research Datalink to calculate the annual diagnosed prevalence of asthma in those aged 2-5 and 6-11; that is the proportion of children in these age groups who have the condition in one year. In addition, we aim to further classify these patients by how severe their asthma is based upon the different medications they have been prescribed and how well their lungs perform based on tests that measure how well a patient breathes. We then wish to see how many children have asthma attacks, how many have other conditions such as allergic rhinitis, allergic conjunctivitis and atopic dermatitis which are common in people with asthma and how many have increased levels of white blood cells. We also want to look at how many times patients contact their general practitioner and hospital services due to their asthma and how much these contacts cost. This will provide valuable data to determine the size of the population with childhood asthma that is difficult to treat with existing medication which may benefit from new medicines.
The study aims to estimate the diagnosed prevalence of paediatric asthma stratified by two age bands (2-5 and 6-11) and to characterise these populations by severity, symptoms, exacerbations, co-morbidity and associated resource use. Data will be selected from the Clinical Practice Research Datalink GOLD dataset for patients linked to the Hospital Episode Statistics (admitted patient care, outpatient and accident and emergency), Office of National Statistics (ONS) mortality and patient level deprivation index datasets. The study will characterise paediatric asthma in 2017/2018. Patients with asthma will be defined by Read or ICD-10 classification codes. Index date will be defined as the latter of 1st January of each year or first diagnosis of asthma and patients will be followed to study end-date defined as the earliest of 31st December of each year or end of follow-up. Point prevalence for the midpoint (30th June of each year) will be calculated using all patients within the specified age bands registered on this date as the denominator. Patients will be classified by severity according to the Global Initiative for Asthma guidelines and patients on individual medications reported. The prevalence of type-2 comorbidities (including allergic rhinitis, allergic conjunctivitis, atopic dermatitis) will be reported. Rates of asthma symptoms defined by Read code, exacerbations defined by either inpatient or accident and emergency contact or acute oral corticosteroid prescription; and mortality defined from the ONS mortality dataset will be reported between from index date and end-date. Rates of healthcare utilisation (primary care, inpatient, outpatient, accident and emergency) between index date and end-date will also be reported and costs applied based on Unit Costs of Health and Social Care for primary care and the national tariff for secondary care. Therapy costs for prescription emanating in primary care will be reported. Descriptive summaries of blood eosinophils and lung function tests will also be reported.
Prevalence; asthma severity; asthma exacerbation; asthma symptoms, resource use; resource costs; mortality; lung function; blood eosinophils; asthma treatment; comorbidities
Christopher Morgan - Chief Investigator - Pharmatelligence Limited t/a Human Data Sciences
Christopher Morgan - Corresponding Applicant - Pharmatelligence Limited t/a Human Data Sciences
Bethan Jones - Collaborator - Pharmatelligence Limited t/a Human Data Sciences
Sara Jenkins-Jones - Collaborator - Pharmatelligence Limited t/a Human Data Sciences
Bethan Jones - Collaborator - Pharmatelligence Limited t/a Human Data Sciences
Sara Jenkins-Jones - Collaborator - Pharmatelligence Limited t/a Human Data Sciences
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Patient Level Index of Multiple Deprivation