Incidence and prevalence of asthma, chronic obstructive pulmonary disease and interstitial lung disease between 2004 and 2023: harmonised analyses of longitudinal cohorts across England, Wales, South-East Scotland and Northern Ireland

Abstract

Background We describe the epidemiology of asthma, chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD) from 2004 to 2023 in England, Wales, Scotland and Northern Ireland (NI) using a harmonised approach. Methods Data from the National Health Service England (NHSE), Clinical Practice Research Datalink Aurum in England, Secure Anonymised Information Linkage Databank in Wales, DataLoch in South-East Scotland and the Honest Broker Service in NI were used. A harmonised approach to COPD, asthma and ILD case definitions, study designs and study populations across the four nations was performed. Age-sex-standardised incidence rates and point prevalence were calculated between 2004 and 2023 depending on data availability. Logistic and negative binomial regression compared incidence and prevalence rates between the start and end of each study period. Linear extrapolation projected incidence rates between 2020 and 2023 to illustrate how observed and projected rates differed. Results Incidence rates were lower in 2019 versus 2005 for asthma (England: incidence rate ratio 0.89, 95% CI 0.88 to 0.90; Wales: 0.66, 0.65 to 0.68; Scotland: 0.67, 0.64 to 0.71; NI: 0.84, 0.81 to 0.86), COPD (England: 0.83, 0.82 to 0.85; Wales: 0.67, 0.65 to 0.69) and higher for ILD (England: 3.27, 3.05 to 3.50; Wales: 1.39, 1.27 to 1.53; Scotland: 1.63, 1.36 to 1.95; NI: 3.03, 2.47 to 3.72). In NHSE, the incidence of asthma was similar in June 2023 versus November 2019, but lower for COPD and higher for ILD. Prevalence of asthma in 2019 in England, Wales, Scotland and NI was 9.7%, 15.9%, 13.2% and 7.0%, respectively, for COPD 4.5%, 5.1%, 4.4% and 3.0%, and for ILD 0.4%, 0.5%, 0.6% and 0.3%. Projected incidence rates were 2.8, 3.4 and 1.8 times lower for asthma, COPD and ILD compared with observed rates at the height of the pandemic. Interpretation Asthma, COPD and ILD affect over 10 million people across the four nations, and a substantial number of diagnoses were missed during the pandemic. All data relevant to the study are included in the article or uploaded as supplementary information. The data used in this study are available in NHS England’s Secure Data Environment (SDE) service for England, but as restrictions apply, they are not publicly available (; ). The CVD-COVID-UK/COVID-IMPACT programme led by the BHF Data Science Centre (; ) received approval to access data in NHS England’s SDE service for England from the Independent Group Advising on the Release of Data (IGARD) () via an application made in the Data Access Request Service (DARS) Online system (ref. DARS-NIC-381078-Y9C5K) (). The CVD-COVID-UK/COVID-IMPACT Approvals & Oversight Board (; ) subsequently granted approval to this project to access the data within NHS England’s SDE service for England. The de-identified data used in this study were made available to accredited researchers only. Those wishing to gain access to the data should contact bhfdsc@hdruk.ac.uk in the first instance. The Northeast - Newcastle and North Tyneside 2 research ethics committee provided ethical approval for the CVD-COVID-UK/COVID-IMPACT research programme (REC No 20/NE/0161) to access, within secure SDE trusted research environments, unconsented, whole-population, de-identified data from EHR data collected as part of patients’ routine healthcare. Our analysis was performed according to a prespecific analysis plan published on GitHub, along with the phenotyping and analysis code (). To ensure anonymity and compliance with the NHSE SDE CVD-COVID-UK consortium rules of statistical disclosure, all reported numbers were rounded to the nearest 5. Counts less than 10 were expressed as '<10'. CPRD has NHS Health Research Authority (HRA) Research Ethics Committee (REC) approval to allow the collection and release of anonymised primary care data for observational research (NHS HRA REC reference number: 05/MRE04/87). Each year CPRD obtains Section 251 regulatory support through the HRA Confidentiality Advisory Group (CAG), to enable patient identifiers, without accompanying clinical data, to flow from CPRD contributing GP practices in England to NHSE, for the purposes of data linkage (CAG reference number: 21/CAG/0008). The protocol for this research was approved by CPRD’s Research Data Governance (RDG) Process (protocol number: 22\_001769) and the approved protocol is available upon request. Linked pseudonymised data was provided for this study by CPRD. Data is linked by NHSE, the statutory trusted third party for linking data, using identifiable data held only by NHSE. Select general practices consent to this process at a practice level with individual patients having the right to opt-out. All work conducted in SAIL Databank was completed under the permission and approval of the SAIL independent Information Governance Review Panel (IGRP) under project number 1387. Researchers can apply for the data and scripts within the SAIL trusted research environment, subject to the standard SAIL project application process (saildatabank.com/contact). The DataLoch work was reviewed and approved under the project number DL\_2022_054. The underlying DataLoch data are available as part of the DataLoch Respiratory Registry—a de-identified registry of linked respiratory data from the South-East Scotland region—which can be accessed by application to the DataLoch service (dataloch.org/connect-with-us). Accredited researchers could only access the de-identified HBS data used in this study by signing a Disclosure Policy Agreement and Research Data Access Agreement. The data was accessible from a secure location, the UK Secure e-Research Platform (UK SeRP). Ethical approval was not required for this study as it was facilitated via HBS. Consent was not required for this study as data was provided in anonymised format, the rights of individuals are respected with adequate privacy protection.