Authors' objectives: Chronic obstructive pulmonary disease affects nearly 400 million worldwide – over a million in the United Kingdom – and is the third leading cause of death. However, there is limited understanding of what prompts a diagnosis, how long this takes from symptom onset and the different approaches to clinical management by primary care professionals. Map out the clinical management and National Health Service contacts from symptom presentation to chronic obstructive pulmonary disease diagnosis and first acute exacerbation of chronic obstructive pulmonary disease in three time periods; construct risk prediction for first acute exacerbation of chronic obstructive pulmonary disease. Chronic obstructive pulmonary disease (COPD) affects nearly 400 million worldwide – over a million in the UK – and is the third leading cause of death. Despite this, there is limited understanding of what prompts a diagnosis, how long this takes from symptom onset and the different approaches to clinical management taken by primary care professionals. This is particularly true regarding people with comorbidities such as asthma and heart failure (HF) that can also cause breathlessness. Map out the clinical management and NHS contacts from symptom presentation to COPD diagnosis and first acute exacerbation, acute exacerbation of chronic obstructive pulmonary disease (AECOPD) (for some patients the latter two will be the same event); investigate whether and how this varied in three cohorts since 2006; rank predictors of the first AECOPD in importance and assess whether and how this changed over time; construct and validate risk prediction models for the first AECOPD.

Authors' results and conclusions: Forty thousand five hundred and seventy-seven patients were diagnosed between April 2006 and March 2007 (cohort 1), 48,249 between April 2016 and March 2017 (cohort 2) and 4752 between March and August 2020 (cohort 3). The mean (standard deviation) age was 68.3 years (12.0); 47.3% were female. Around three-quarters were diagnosed in primary care, with a slight fall in cohort 3. Compliance with National Institute for Health and Care Excellence diagnostic guidelines was slightly higher in cohorts 2 and 3 for all patients; 35.8% (10.0% in the year before diagnosis) had all four elements met for all cohorts combined. Multilevel modelling showed considerable between-practice variation in spirometry. The survey on the charity website had 156 responses by chronic obstructive pulmonary disease patients. Many respondents had not heard of the condition, hoped the symptoms would go away and identified various healthcare-related barriers to earlier diagnosis. Clinical Practice Research Datalink analysis showed notable changes in post-diagnosis prescribing from cohort 1 to 2, such as increases in long-acting muscarinic antagonist (21.7–46.3%). Triple therapy rose from 2.9% in cohort 2 to 11.1% in cohort 3. Documented pulmonary rehabilitation rose from just 0.8% in cohort 1 to 13.7% in cohort 2 and 20.9% in cohort 3. For all patients combined, the median time to first acute exacerbation of chronic obstructive pulmonary disease in patients who had one was 1.4 years in cohorts 1 and 2. Acute exacerbation of chronic obstructive pulmonary disease prediction models identified some consistent predictors, such as age, deprivation, severity, comorbidities, post-diagnosis spirometry and annual review. Models without post-diagnosis general practitioner actions had a c-statistic of around 0.70; the highest c-statistic was 0.81, for cohort 2 with post-diagnosis general practitioner actions and 6-month follow-up. All models had good calibration. The three most important predictors in terms of their population attributable risks were being a current smoker and offered smoking cessation advice (32.8%), disease severity (30.6%) and deprivation (15.4%). The highest population attributable risks for variables with adjusted hazard ratios 

Authors' methods: Retrospective cohort study and cross-sectional survey. Primary care. Patients with incident chronic obstructive pulmonary disease aged > 35 years in England. None. First acute exacerbation of chronic obstructive pulmonary disease. Clinical Practice Research Datalink Aurum; new online survey. Symptom recording and chronic obstructive pulmonary disease diagnosis vary between practice; predicted forced expiratory volume in 1 second had many missing values. The project involved the quantitative analysis of an existing database and a new survey. The main component used the Clinical Practice Research Datalink (CPRD), which collects deidentified patient electronic health records from participating general practitioner (GP) practices; its Aurum version includes healthcare records from GP practices using EMIS® software, representing around 13% of the population in England. It includes patient-level data on demographics, tests, symptoms, diagnoses, therapies, prescriptions and referrals to secondary care. Patient-level data from these practices were linked by CPRD staff to the Office for National Statistics death register, Hospital Episode Statistics and Index of Multiple Deprivation at small area level. We included all individuals aged over 35 years with COPD diagnosed between 1 April 2006 and 31 March 2007 (cohort 1) and between 1 April 2016 and 31 March 2017 (cohort 2); a smaller COVID-era group for March–August 2020 made up cohort 3. For each patient, the index (diagnosis) date was defined as the first record of COPD, either in primary care records via SNOMED-CT codes or in hospital admission data via International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes. Patients had to have at least 1 year’s registration with the GP before the diagnosis date. Patient characteristics were described for the year up to and including the diagnosis date; GP actions were also described in the year before and since diagnosis. The first AECOPD was identified using our group’s published algorithm and was restricted to hospital admissions to reliably capture the most serious ones. Much of the analysis was descriptive, including cumulative incidence plots for the time to first AECOPD by cohort. GP actions before diagnosis were compared with the National Institute for Health and Care Excellence (NICE) guidelines, which recommend spirometry, chest X-ray, full blood count (FBC) and the calculation of body mass index (BMI). These ‘routes to diagnosis’ analyses were stratified by pre-existing HF and asthma, conditions that share some symptoms and that could cause diagnostic confusion. Multilevel models assessed the variation between GP practices in the proportion of patients receiving spirometry in the 6 months prior to or after diagnosis; funnel plots were used to count statistical outliers at 2 and 3 standard deviations (SD) from the mean. Prescriptions for the main classes of medication were noted for the year following diagnosis. A set of Fine and Gray regression models quantified the association between patient characteristics, GP actions and first AECOPD in patients not diagnosed via an AECOPD, accounting for the competing risk of death from non-COPD causes: model 1 contained only patient factors, model 2 additionally contained pre-diagnosis GP actions and model 3 also included post-diagnosis GP actions. Population attributable risks (PARs) were calculated for statistically significant risk factors. The focus for the reporting of the model outputs was on the model containing patient characteristics and pre-diagnosis GP actions. We developed an online survey to investigate COPD patients’ retrospective perceptions of their initial symptoms, what they did after developing those symptoms, what kind of professional advice was sought and year of diagnosis in order to distinguish between COVID and pre-COVID eras. It was designed jointly through a series of discussions by the project team at Imperial College London, which included researchers and patient representatives, and the teams at Asthma + Lung UK and the Taskforce for Lung Health, including its own patient advisory group. This was administered via the charity and GPs contributing to CPRD.

Project Status: Completed

URL for project: https://www.journalslibrary.nihr.ac.uk/programmes/hsdr/17/99/72

Year Published: 2024

URL for published report: https://www.journalslibrary.nihr.ac.uk/hsdr/CGTR6370

URL for additional information: English

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: United Kingdom

DOI: 10.3310/CGTR6370

Organisation Name: NIHR Health and Social Care Delivery Program

Contact Name: Rhiannon Miller

Contact Email: rhiannon.m@prepress-projects.co.uk