Chronic obstructive pulmonary disease (also known as chronic bronchitis or emphysema) is a lung disease commonly caused by smoking which leads to breathlessness, cough, and recurrent chest infections. The number of people in the UK with chronic obstructive pulmonary disease is said to be increasing but many cases of the disease are thought to be undiagnosed. There have been studies in the past looking at the number of people in the UK with chronic obstructive pulmonary disease, but the numbers are not up to date. We will provide current estimates for the size of the chronic obstructive pulmonary disease population, looking at what happens when different definitions of chronic obstructive pulmonary disease are used to define who has the disease. To do this, we will look at both GP patient records and hospital admission records. This study will also provide insight into how the size of the chronic obstructive pulmonary disease population varies across age, gender, socioeconomic status, disease severity (indicated by results of lung tests), and prescribed inhalers. We aim to describe how the above may have changed over time and establish a baseline from which to observe changes moving forward. The results will also provide context when looking to find people with chronic obstructive pulmonary disease. It is important to note that some people with chronic obstructive pulmonary disease won’t visit the doctors and will never receive a diagnosis, nor have healthcare records suggestive of chronic obstructive pulmonary disease, and therefore will not be captured in this study.
The objective of this study is to obtain an up-to-date estimate of the prevalence of chronic obstructive pulmonary disease (COPD) in England, to understand the make-up of the COPD population, and to observe the temporal trends in annual prevalence over the past two decades (2000 to 2020). This study will be descriptive and use CPRD Aurum data linked with Hospital Episode Statistics (HES) Admitted Patient Care (APC) data. Annual COPD prevalence will be stratified by age, sex, region, socioeconomic status (using linked Index of Multiple Deprivation (IMD) data), COPD medication, and COPD severity (Medical Research Council (MRC) Grade, Global Initiative for Obstructive Lung Disease (GOLD) stage, and pulmonary rehabilitation referral status). COPD prevalence will be determined for each year between 2000 and 2020, inclusive, using a validated disease definition of Read V2 codes. We will also determine prevalence based on a disease definition using Quality and Outcomes Framework (QOF) codes, and symptom codes in smokers without a diagnosis of asthma. We will also capture the prevalence of COPD in secondary care records (HES) relative to primary care. The overall annual number of adults registered in the CPRD will be used as the denominator. Additionally, the prevalence of patients having ≥1 moderate or severe COPD exacerbation per year will be calculated by calendar year. We will consider using logistic regression to estimate changes in prevalence of COPD-related events across time and to estimate changes in COPD diagnosis based on case finding and spirometry testing, if appropriate and numbers allow. This will benefit public health as it will reveal the burden to the NHS of COPD, and therefore inform appropriate resource allocation.
Prevalence of COPD captured in primary care records (when using either a validated definition of COPD or the QOF definition); Prevalence of COPD captured in secondary care records
Jennifer Quint - Chief Investigator - Imperial College London
Philip Stone - Corresponding Applicant - Imperial College London
Michael Osen - Collaborator - British Lung Foundation
HES Admitted Patient Care;Patient Level Index of Multiple Deprivation