COPD: definition, diagnosis, prevalence and societal impact

Chronic obstructive pulmonary disease (COPD) is a common, preventable, heterogeneous chronic lung condition characterised by ongoing symptoms of shortness of breath, cough, sputum production and/or exacerbations. It affects the airways and/or alveoli, resulting in progressive airflow obstruction over time. It is caused not only by tobacco smoking but also inhalational injury from toxic particles and gases in household and outdoor air pollution, as well as environmental/host factors such as abnormal early lung development.1 COPD can take a number of years to develop and increasingly contributes to multimorbidity within an ageing population. COPD causes 30 000 deaths per year, second only to lung cancer (for which it is a risk factor) as a driver of respiratory deaths, and it is the fifth biggest cause of death overall in the UK.2–4

In the UK, 1.4 million people have a COPD diagnosis, making it the second most common lung disease in the UK after asthma.3 4 Despite this, it is likely that reported COPD prevalence is underestimated, with many patients historically undiagnosed or mis-diagnosed; evidence from the National Institute for Health and Care Excellence (NICE) indicates that up to two million people in the UK could have undiagnosed, and, therefore, untreated COPD,3–5 contributing to avoidable emergency hospital admissions and NHS pressures as well as distress for patients and families.

COPD should be considered in anyone with appropriate symptoms and risk factors, and then confirmed with quality-assured spirometry and/or supplemental investigations. Postbronchodilator forced spirometry demonstrating airflow obstruction that is not fully reversible is the minimum required to confirm the diagnosis, but it is important to note that other lung conditions, for example, chronic asthma can also cause this finding. Therefore, a valid diagnosis of COPD requires careful assimilation of the lung function results in the context of the history and clinical findings, and exclusion of other differential diagnoses. Some patients with emphysema as part of the spectrum of COPD may have preserved spirometry; where there is diagnostic uncertainty, this should be discussed with a specialist. A patient presenting with symptoms of an exacerbation in primary care who does not already have a diagnosis of COPD should raise clinical suspicion of the diagnosis, however evidence suggests many of these opportunities are missed.6

Even before the COVID-19 pandemic, there were already problems with COPD care, with a quarter of people being diagnosed five or more years after developing symptoms, and less than one in five receiving all fundamentals of good care,4 namely appropriate vaccinations, treatment for tobacco dependence, pulmonary rehabilitation, a self-management plan and optimised treatment of comorbidities. An important sixth element of good COPD care is a review of inhaled therapies and a check of inhaler technique. During the COVID pandemic, new diagnoses of COPD in the UK fell by 51%, and many barriers remain to patients and clinicians accessing timely quality-assured diagnostic spirometry.7 This impacts the poorest communities most, where health inequalities are greatest.8 Poor lung health is both caused by, and exacerbates, health inequality due to the close links between deprivation, tobacco dependence, exposure to poor air quality, housing and diet, and higher-risk occupations.9 People living in deprived areas are two-and-a-half times more likely to have COPD and nearly two times as likely to develop lung cancer,10 and higher numbers of acute respiratory admissions occur in areas of greatest socioeconomic hardship.11 The need for early and accurate diagnosis as well as better long-term care for people for lung conditions is highlighted in the NHS Long Term Plan and the government’s Major Conditions Strategy.12 NHS England’s recent CORE20PLUS5 initiative aims specifically to narrow health inequalities in people with COPD with a particular focus on increasing uptake of COVID, influenza and pneumonia vaccines as well as treating tobacco dependence across the most deprived areas in England.13

COPD exacerbations

Acute exacerbations of COPD are serious adverse events, which drive lung function decline as well as worsening functional and health status.14 While the majority of these are managed in an outpatient or home setting, there are around 130 000 acute admissions due to COPD exacerbations each year; this is the second most common reason for hospital admission and costs the NHS just under £1.4 billion annually.6 COPD exacerbations are also a major contributor to the year-on-year increase in respiratory-driven acute winter pressures in the NHS.15

Definition

A COPD exacerbation is defined as an acute episode of increased breathlessness and/or cough, sputum (change in volume/colour) and wheeze, beyond a patient’s usual symptoms. It is usually an inflammatory event triggered by infection (respiratory viral or bacterial), pollution, other ambient changes (eg, high or low temperatures) or another insult to the airways.1 3 Exacerbations caused by respiratory viruses (most commonly rhinovirus, influenza, parainfluenza and metapneumovirus) are often more severe, last longer and result in more hospital admissions, as seen in winter. Not all exacerbations are reported to a healthcare professional or result in treatment, but these episodes also have an impact on health status over time,16 so it is important that patients know how to recognise and act on them, and that healthcare professionals ask about exacerbation frequency at planned reviews.

Classification of severity and place of care

Exacerbations may be mild, requiring treatment with increased use of inhaled short-acting beta₂ agonist bronchodilators (SABA) only, which can be managed in a patient’s usual environment; moderate, where short-acting bronchodilators and oral corticosteroids with or without antibiotics are warranted, with consideration for the need for additional monitoring and support; or severe, where the patient requires an acute assessment ± consideration of hospital admission.3 5

Clinical assessment is key to defining the severity of a patient’s exacerbation and the appropriate treatment plan, and a suggested guide is shown in table 1. It is important to consider and investigate other differential diagnoses, which patients with COPD are at increased risk, including pneumonia, pulmonary embolism, pneumothorax, heart failure or myocardial infarction where appropriate.3 5 A number of factors can indicate the need for hospital referral and management of a patient with a COPD exacerbation and those are shown in box 1.

Acute respiratory failure, associated with hypoxia and/or hypercapnia, is an indication of a severe exacerbation requiring hospital assessment and therefore measurement of oxygen saturation is an important aspect of clinical assessment in primary care. However, pulse oximeters can underestimate or overestimate oxygen saturation levels where these are borderline, and readings can also change quickly. Therefore, when deciding on a treatment plan, oxygen saturation levels should be understood in the context of the overall clinical presentation of a patient as well as their usual and/or target oxygen saturations. This is particularly relevant in patients with COPD with established respiratory failure on home oxygen, or those at known risk of/with a previous history of hypercapnic respiratory failure, where lower target saturations (eg, 88%–92%) are likely to be appropriate during an acute illness.

There are two important safety issues to be aware of when using a pulse oximeter. First, pulse oximeters may be 3–4 times less accurate in patients of colour, because when originally developed they were not validated in racially diverse populations.17 Therefore, subclinical hypoxemia is more common in black patients than in white patients, with associated increased mortality; clinical decisions should not be based on pulse oximetry readings alone in this group. Second, adult oximeter probes can be attached to either a finger or an ear but are not interchangeable between these sites, where they will give inaccurate readings if the incorrect site is used. Staff using them must be aware of this and appropriately trained in their correct placement.18 Additional information on the use and regulation of pulse oximeters is available from the Medicines and Healthcare products Regulatory Agency (MHRA).19

Models of care for managing COPD exacerbations

Hospital at home and assisted discharge schemes are safe and effective and can be used as an alternative way of caring for some patients with COPD exacerbations who would otherwise need to be admitted or stay in hospital.20 Teams delivering this care should be multiprofessional, have knowledge and experience of managing COPD and have access to specialist advice/review and escalation pathways where needed. Building on the experience of remote monitoring and virtual care during the COVID-19 pandemic and a growing evidence base, since 2022 NHS England has rolled out a programme of virtual wards to support patients who would otherwise be in hospital to receive acute care, remote monitoring and treatment in their own home (or usual place of residence) for up to 14 days.21 COPD is one of the conditions identified for this programme and therefore where this is available, patients with COPD exacerbations may be referred either from primary or secondary care to a virtual ward, where a senior practitioner can oversee their care at home, usually via a digital platform, which allows remote monitoring and escalation of treatment as appropriate. Patients should be made aware of this option where it exists; individual preference for place of treatment should be considered in all decision-making about pathways of care.

Pharmacological treatment

The goals of treatment for COPD exacerbations are to minimise the negative impact of the current episode, support recovery and prevent complications. Where pharmacological treatment is appropriate, early treatment improves outcomes. This should be balanced against appropriate stewardship of antibiotic and corticosteroid use.

Key points for pharmacological management include:

• Treatment with inhaled SABA, with or without anticholinergics, is recommended as initial bronchodilator therapy.5 Systematic reviews have shown no difference in efficacy between administering SABA via a metered dose inhaler plus spacer versus a nebuliser, so mode of delivery should be based on what is best suited to the patient’s clinical need.22 Continuous nebulisation is not recommended due to adverse effects of tremor and tachycardia, and if used should be air driven rather than oxygen driven to reduce the risk of hypercapnia. Therefore, SABA therapy through an inhaler as one or two puffs every hour for two or three doses and then every 2–4 hours based on the patient’s response is a reasonable approach for most patients.1

• Systemic corticosteroid therapy (30 mg prednisolone orally for 5 days) is indicated for patients with moderate or severe breathlessness, which interferes with usual activities, as this treatment improves lung function, oxygenation and recovery time and shortens duration of hospital stay.1 As there is an association with an increased risk of pneumonia with both high dose inhaled and oral steroids,23 use of prednisolone in COPD should be confined to patients with a significant acute exacerbation.

• Exacerbations with increased breathlessness, sputum volume and purulence are likely to be associated with a bacterial infection and in these circumstances, evidence supports the use of antibiotics, which improve recovery time, reduce the risk of relapse and treatment failure and shorten hospital stay.24 Point of care testing with C reactive protein where available may aid in clinical decision-making.25 The choice of (oral) antibiotic should be based on local bacterial resistance patterns and clinical guidelines and also take into account the patient’s previous exacerbation and hospital admission history, risk of complications and previous sputum culture results. Table 2 sets out recommendations from NICE guidance.5 26 27

Patients should be informed about possible adverse effects of treatment and advised to seek help if symptoms do not start to improve, or worsen, within an agreed time frame; they should be made aware of how, when and from whom to seek assistance. In this situation, patients with an exacerbation of COPD should be reassessed, taking into account other possible diagnoses, previous antibiotic use which may have led to resistant bacterial infection, or other ongoing complications, and specialist advice sought. Patients with a new or changing oxygen requirement, or who need ventilatory support must be assessed in hospital setting.

Most patients experience symptoms of an exacerbation for 7–10 days, but some episodes may last longer, and up to 20% of patients may not have recovered to their baseline state at 8 weeks. Patients experiencing frequent exacerbations (≥2 per year) have worse health status and morbidity than those who do not, and experience worse outcomes. An exacerbation should prompt timely clinical review to ensure the diagnosis is correct, management is optimised, recovery is on track and a personalised care approach is taken to identify risks and prevent the next exacerbation. Patients who continue to experience exacerbations despite treatment optimisation in primary care should be referred to a specialist COPD clinic, to rule out complicating factors (eg, bronchiectasis or atypical infection) and to consider other interventions which can be offered in secondary care to reduce exacerbation frequency, such as sputum clearance adjuncts (eg, oscillatory positive pressure devices); maintenance macrolide therapy; anti-inflammatory medication such as roflumilast, mucoregulators and lung volume reduction.

Preventing the next exacerbation: moving beyond the prescription to high value care

Exacerbations are an opportunity to focus on measures of personalised and high value care which are often missed; optimising these proactively through a whole person approach can prevent future exacerbations and minimise their impact. Key evidence-based treatments to review for each patient include:

• Identifying and treating tobacco dependence, through very brief advice, offer of referral to a specialist smoking cessation service and prescription of appropriate pharmacotherapy. All clinicians who see patients with COPD and treat exacerbations should understand the evidence base around treating tobacco dependence and take every opportunity to offer patients effective treatments, including combination nicotine replacement therapy (NRT), bupropion, cytisine and varenicline as well as referral to specialist behavioural support.28 (An unlicensed form of varenicline may be available in the UK. Use of an unlicensed medicine may be considered if there is no suitably licensed medicine that will meet the patient’s need.29 30)

• Although no nicotine-containing e-cigarettes (vapes) have been licensed by theMHRA as an aid to stopping smoking, there is evidence that they are more effective than NRT as well as being substantially safer than smoking.31 32 There are calls for nicotine-containing vapes to be made accessible as part of a tobacco-dependent treatment pathway in primary care for patients with COPD who smoke.33

• Ensuring that patients are up to date with influenza, COVID-19 and pneumococcal vaccination.5

• Discussing the benefits of and offering referral to pulmonary rehabilitation, a strongly evidence-based treatment which improves breathlessness, functional capacity, health-related quality of life and mental health in COPD. Pulmonary rehabilitation should be offered to any patient with COPD who is functionally limited by breathlessness to prevent exacerbations; at a post exacerbation review; and after an acute hospital admission due to an exacerbation of COPD.5 34

• Ensuring that the patient is prescribed and adherent to evidence-based pharmacological therapies, which are shown to reduce symptoms as well as the frequency and severity of exacerbations and improve exercise tolerance and health status. This includes reviewing and optimising inhaler technique at every opportunity. An exacerbation is an opportunity to review whether inhaled steroids are appropriate, or not, for a patient with COPD, taking into account eosinophil count, concomitant asthma diagnosis and risk of pneumonia.1

• Agreeing a personalised written self-management plan, including an action plan for what to do and how to seek support during an exacerbation and checking the patient’s understanding and ability to use this.5 35 It is good practice to ensure this is in place before issuing a ‘COPD rescue pack’ of antibiotics and steroids, and that the patient understands when and how to use their rescue pack. Issuing rescue packs on repeat prescription is not advised due to increased risk of diabetes, osteoporosis and antibiotic resistance.36 It is good practice to review and track the number of rescue packs a patient is using; ≥2 per year should prompt further investigation and action.

• Identifying and optimising comorbidities which frequently cluster with and complicate COPD symptoms, exacerbation frequency and outcomes, especially anxiety and depression.

Proactive care: who are your patients at rising risk of exacerbation?

Primary care teams are ideally placed to identify and intervene proactively with patients who are most at risk of exacerbation and poor outcome. Preparing for winter is an optimal time to consider this, but the principles apply throughout the year of care, and NHS England has produced a resource pack for primary care setting out how to approach this.37 A number of free population health management tools are available to enable COPD registry searches and risk stratification.38 Criteria for focus include patients on the COPD register who in the last 12 months:

• have not had an annual review

• have had two or more courses of oral steroids

• have had two or more acute admissions.

As well as the key fundamentals described above, other interventions which can be considered include:

• advice and resources on keeping well in winter39

• signposting to Met Office alerts40

• involving social prescribing link workers to support patients with housing, food and fuel poverty

• involving a health and well-being coach to support self-management strategies

• involving CORE20plus five community connectors41

• involving a care coordinator for patients with complex care and support needs

• joint working with community/integrated COPD team colleagues for specialist support

• coproducing a personalised advance care plan, with input from palliative care colleagues, for patients with severe disease and high symptom burden.