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Battling the burden of COPD: what's new?

David Bellamy
BSc MBBS FRCP MRCGP
GP
James Fisher Medical Centre
Bournemouth
Member NICE COPD Committee
Chair of Trustees GPIAG (General Practice Airways Group)
E:david.bellamy@virgin.net

Chronic obstructive pulmonary disease (COPD) is a common respiratory disorder causing persistent and progressive symptoms and a serious impairment of quality of life. It affects 1-2% of the population, although this may represent half the true figure. Men are more commonly affected, but over the last 30 years the prevalence in women has steadily increased. COPD causes a large level of workload in both primary and secondary care - 13% of all acute medical admissions are due to exacerbations of COPD - and a financial burden to the NHS of £600m.
Until recently, COPD has been an underdiagnosed and inadequately managed condition. However, in 2004 there will be a series of key events that should help to raise the level of interest and understanding of this important disorder to the level it merits.

  • In February a new set of evidence-based ­guidelines are to be produced by NICE, and the British Thoracic Society COPD Consortium will be producing a short summary and other teaching materials that will be distributed to all GPs and practice nurses in the UK.
  • The new GMS contract, to commence in April 2004, has an incentive to correctly diagnose and assess patients with COPD.
  • The NHS Primary Care Collaborative has set up pilot PCTs to investigate better COPD ­management. This is likely to be made standard practice nationally during 2004.

Defining COPD
According to the National Institute of Clinical Excellence 2004 definition,(1) COPD is characterised by airflow obstruction. The airflow obstruction is usually progressive, not fully reversible and does not change markedly over several months. The disease is predominantly caused by smoking.

  • Airflow obstruction is defined by spirometry as a reduced FEV(1) (the forced expired volume in the first second of the blow) of less than 80% of ­predicted value, plus a reduced FEV(1)/FVC ratio (FVC is the total volume of air that can be blown from the lungs - the vital capacity) below 70%.
  • Airway obstruction is due to a combination of ­airway and lung tissue damage.
  • Damage is the result of chronic inflammation that differs from that seen in asthma and which is ­usually the result of tobacco smoke. In the UK, approximately 85% of all COPD is due to ­smoking.
  • Significant airflow obstruction may be present before the individual is aware of it.
  • COPD produces symptoms, disability and impaired quality of life that may respond to ­pharmacological and other therapies that have limited or no impact on the airflow obstruction.

There is no single diagnostic test for COPD. Making a diagnosis relies on clinical judgement based on a combination of history, age, physical examination and confirmation of the presence of airflow obstruction using spirometry.
COPD is a spectrum of conditions that include:

  • Chronic bronchitis.
  • Emphysema.
  • Longstanding asthma that is no longer responsive to standard therapy.

Making a diagnosis
The initial step is thinking of COPD as a potential cause of breathlessness or cough. The diagnosis is suspected on the basis of symptoms and history and confirmed by spirometry.

Symptoms
A diagnosis of COPD should be considered in patients over the age of 35 years who have a risk factor - usually smoking - and who present with one or more of the following symptoms:

  • Persistent exertional breathlessness.
  • Chronic cough.
  • Regular sputum production.
  • Frequent winter bronchitis.
  • Wheeze.

Spirometry
Spirometry is the gold standard for confirming a diagnosis of airflow obstruction (see Figure 1). A combination of an FEV(1) below 80% of the predicted value and an FEV(1)/FVC ratio below 70% is essential for showing the presence of airflow obstruction. Spirometry also provides a measure of disease severity, and the postbronchodilator FEV(1) is correlated with survival and prognosis.

[[NIP15_fig1_64]]

It is recommended that all practices should have access to or possess a spirometer. It is essential that staff using the spirometer are trained in performing the blowing technique and can understand and interpret the results. Such skills need to be kept up-to-date, and the equipment needs to be adequately maintained.
Spirometry should be performed on first diagnosis. Thereafter, spirometry should not be performed more often than once yearly unless there are exceptionally good responses to therapy, which may lead to a diagnosis of asthma, or alternatively a more rapid progression of symptoms than would be expected.

Severity levels by spirometry
The NICE Guidelines in collaboration with the American, European and GOLD Guidelines have agreed new spirometric severity levels that will for the first time provide standard levels of FEV(1) on a global basis. These levels differ from the old BTS Guidelines (see Table 1).

[[NIP15_table1_64]]

Other investigations
At the time of first diagnosis, other investigations that should be performed include:

  • A chest X-ray. This may be normal in mild or moderate COPD, but as other diseases such as lung cancer are common in smokers, it is a useful way of looking for other pathologies.
  • A full blood count to look for polycythaemia.
  • Body mass index.
  • Alpha(1)-antitrypsin level in patients presenting under the age of 45 years and perhaps those with a strong family history of emphysema.
  • Oxygen saturation with pulse oximetry in patients with an FEV(1) below 50% predicted looking for early cor pulmonale. An oxygen saturation below 92% may need referral to a respiratory specialist for further investigation.

Reversibility testing
The main purpose of performing bronchodilator and corticosteroid reversibility testing is to identify those patients with a larger response who are more likely to have asthma. The new NICE Guidelines and also the American and European Guidelines have softened the need for performing these tests in all patients. In many instances, the clinical picture and spirometry may be adequate to make a diagnosis of COPD, although there should always be an awareness of those patients who show a greater than expected response to therapy who may be asthmatic and require repeat spirometry and perhaps twice daily home peak flow monitoring.
The reasoning behind this change is based on a number of studies, which have shown that:

  • Repeated FEV(1) measurements may vary by up to 100ml from day to day.
  • Reversibility testing in a given patient can be inconsistent and not reproducible.
  • Overreliance on a single reversibility test may be misleading unless the response in FEV(1) increase is greater than 400ml.
  • Response to long-term therapy, particularly steroids, is not predicted by acute testing.

The main message seems to be that reversibility testing should be carried out if there is any doubt about the diagnosis, particularly differentiating COPD from asthma.
Reversibility testing should be carried out in the traditional way, with a high dose of bronchodilator via a large volume spacer or with prednisolone 30mg per day for 2 weeks. An increase in FEV(1) of 400ml over baseline is suggestive of asthma.

Severity assessment
Although FEV(1) % predicted is a recognised objective measure of COPD severity, there may be severe symptomatic disability in patients with only mild airflow obstruction. COPD is now known to be a systemic disease, with weakness and fatigue of muscles as well as the longer-term adverse effects on the pulmonary ­circulation and heart.
More disabled patients are depressed and socially isolated. A more accurate assessment of severity should take into account that breathlessness can be caused by parenchymal lung damage to the alveoli as well as airflow obstruction. Patients frequently develop hyperinflated lungs, which make the work of breathing difficult. Thus a more complete assessment of the patient might also include:

  • A breathlessness scale such as the MRC (Medical Research Council) scale (see Table 2).

[[NIP15_table2_66]]

  • An estimate of exercise capability.
  • Health status questions.
  • Enquiry about mood and social situation.

Identifying early disease
In theory, finding patients with early COPD and helping them stop smoking may prevent further development of disease. Fletcher and Peto showed that patients with airflow obstruction who stopped smoking had a decline in lung function that was similar to a nonsmoker (see Figure 2).(2) Is it therefore worth screening your smoking population over 40 years? At present there are no large studies to answer this important question, but the data available suggest that screening of smoking populations over 40 will yield about 20% with abnormal airflow obstruction. A case-controlled study showed airflow obstruction in 27% of smokers over 35 years who also had persistent cough.(3)

[[NIP15_fig2_66]]

There are also some early pointers to suggest that patients who are found to have abnormal lung function are more likely to stop smoking.

Managing stable COPD

Smoking cessation
Stopping patients from smoking remains the single most important intervention as it is the only therapy that slows the rate of decline in lung function and improves prognosis. Although nothing will return lung function to normal in COPD, stopping smoking may allow a productive cough to disappear. Every opportunity should be taken to advise and help patients to quit. Unless contraindicated, pharmacotherapy with nicotine replacement or bupropion should be used to optimise quit rates.

Inhaled bronchodilator therapy
Short-acting bronchodilators (b-agonists and anticholinergics) are the cornerstone of symptomatic therapy. They help to relieve breathlessness and wheeze and to improve activity levels and walking distance. Their effectiveness is often poorly assessed by performing spirometry - it is more relevant to ask patients to describe any symptomatic changes after a clinical trial with the inhaler over about 4 weeks.
If symptomatic control remains inadequate, long- acting bronchodilators (salmeterol, formoterol, tiotropium) should be added as they provide added benefits in improving quality-of-life indices and also reduce frequency of exacerbations. Theophyllines are helpful in patients who find inhalers difficult but do suffer from more serious side-effects.

Inhaled corticosteroids
Evidence shows the main clinical area where inhaled steroids are beneficial is in patients with an FEV(1) less than 50% predicted who are having acute exacerbations or patients in the new severe group. They reduce frequency of exacerbations, have small benefit in symptoms, and slow the rate of decline of quality of life.
The data suggest a higher dose of steroid is probably required, but there are no data to point to the ideal dose.
Regular oral steroids are not recommended.

Combined inhalers
There is good evidence for an additive effect of b-agonist and anticholinergics.
Recently, there have been a number of studies that have shown added benefits in quality of life, exacerbation frequency and lung function with combined long-acting b-agonists and inhaled corticosteroids.

Pulmonary rehabilitation
A very effective form of therapy carried out by a multi-disciplinary team over a 6-week period with far greater benefits in improved quality of life than drug therapy. Sadly, there are still far too few units available for such treatment.

Influenza and pneumococcal vaccination - ­recommended

Management of exacerbations

Preventing exacerbations
Exacerbations of COPD cause major worsening of symptoms and deterioration of quality of life to patients, and cause a considerable workload to both primary and secondary care. Some therapies, such as long-acting bronchodilators, corticosteroids and rehabilitation, may reduce the frequency of attacks. In addition, a simple action plan where patients are provided with a supply of antibiotics and prednisolone to use early when symptoms of exacerbations occur may reduce the severity and duration of attacks and prevent hospital admissions.
Symptoms of exacerbations are:

  • Increasing breathlessness and chest tightness.
  • Sputum purulence - green or yellow colour is an indicator for antibiotics.
  • Increase in sputum volume.

Exacerbations are often linked to colds and upper respiratory tract infections (URTIs) and take 1-2 weeks to recover.

Treatment

  • Add or increase bronchodilators.
  • Antibiotics.
  • Prednisolone 30mg once daily for 7-14 days.
  • Consider the need for hospital admission.

Conclusion
COPD is a common disease causing much suffering to patients. Effectively diagnosing the disease and providing the many forms of beneficial therapy can greatly improve symptoms and quality of life.

[[NIP15_pp_67]]

References

  1. National Institute of Clinical Excellence. Guideline to be published in February 2004 or in Thorax in March 2004. London:NICE; 2004.
  2. Fletcher C, Peto R. The natural history of chronic airflow obstruction. BMJ 1977;1:1645-8.
  3. Van Schayck CP, et al. Detecting patients at a high risk of developing chronic ­obstructive pulmonary disease in general practice: cross sectional case finding study. BMJ 2002;324:1370-4.

Resources
British Thoracic Society Can access the NICE guidelines, all booklets, charts and ­teaching materials
W:www.brit-thoracic.org.uk
British Lung Foundation Can access patient materials on COPD
W:www.britishlungfoundation.org