Around 5.4 million people are treated for asthma in the UK. Asthma is treated with inhaled medication; patients can use a ‘reliever inhaler’ for immediate symptom-relief, and/or a ‘preventative inhaler’ to prevent asthma symptoms occurring. All reliever inhalers in the UK contain a type of drug called a short acting beta-agonists (SABA). All preventative drug regimens should contain an inhaled steroid (ICS). Clinical guidelines inform how and when inhalers should be used; for example, a patient with mild asthma may only use SABA, or only use SABA and low dose ICS, but a patient with moderate disease may use SABA and high dose ICS (as well as other medications). The clinical guidelines specify that a patient should have optimal asthma control (no asthma symptoms) and that a sign that they do not is if they are using their SABA inhaler more than twice a week; if a patient is using SABA frequently, it is likely that they should be on a higher ICS dose. Therefore, this study aims to, firstly, describe the SABA and ICS inhaler prescription patterns in children and young people in England over the past decade, and secondly, the effect these inhalers have on asthma health outcomes and asthma-related healthcare resource utilisation.
Firstly, we will describe the current asthma population in England in people aged 4-17 in terms of SABA and ICS prescriptions, and the temporal patterns seen during the study period. Patients will be categorised according to their SABA and ICS use in terms of British asthma guidelines and Global Initiative for Asthma (GINA) guidelines. Next we will use a cohort study design to compare the effects of different patterns of SABA prescriptions on health outcomes (main outcome will be exacerbations; using Cox models) and healthcare resource utilisation (main outcome will be GP visits; using Poisson or negative binomial models, depending on distribution) (dataset will be all eligible current asthma patients in CPRD aged 4-17 eligible for linkage with HES-ONS). SABA prescriptions will be the main exposure, derived from 6 months of prescription data before the study start; the categories used will depend on the findings of the descriptive analysis. Models will be adjusted for multiple potential confounders, in particular ICS prescriptions. If the descriptive analysis shows patients change between SABA or ICS categories over time then this will be taken into account; firstly the regression models will censor patients once they change to a different exposure category, secondly, in sensitivity analyses we will use extensions to the regression models to take into account the time-varying exposures. If numbers allow we will investigate mortality as an outcome. We will also determine total costs (healthcare and environmental (CO2 emission) ). We will explore the use of other asthma treatments (leukotriene receptor antagonists (LTRA) and oral corticosteroids. We will also include co-existing conditions (allergies, asthma phenotypes, depression) in the models as appropriate.
Incidence; prevalence; treatment patterns; exacerbations; health resource utilisation; mortality; costs; total CO2 emission
Ekaterina Maslova - Chief Investigator - AstraZeneca Ltd - UK Headquarters
Jennifer Quint - Corresponding Applicant - Imperial College London
Ann Morgan - Collaborator - Imperial College London
Constantinos Kallis - Collaborator - Imperial College London
Graham Roberts - Collaborator - University of Southampton
Ian Sinha - Collaborator - Alder Hey Children’s NHS Foundation Trust
Mina Khezrian - Collaborator - AstraZeneca Ltd - UK Headquarters
Ralf van der Valk - Collaborator - AstraZeneca Ltd - UK Headquarters
Sofie Arnetorp - Collaborator - Astra Zeneca R&D Molndal Sweden
Trung Tran - Collaborator - Astra Zeneca Inc - USA
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation