Clinical Review: COPD

Contributed by Dr Simon Bourne, consultant in respiratory medicine, University Hospital Southampton NHS Foundation Trust

Spirometry is used to assist the diagnosis of airways obstruction (Photograph: SPL)
Spirometry is used to assist the diagnosis of airways obstruction (Photograph: SPL)

Section 1: Epidemiology and aetiology
Chronic obstructive pulmonary disease (COPD) is an umbrella term used to describe an obstructive lung disease consisting of two distinct pathologies - chronic bronchitis and emphysema.

Chronic bronchitis is associated with airways inflammation, increased sputum production and bacterial infection. Emphysema is characterised by lung destruction, formation of lung bullae, loss of elastic recoil and hyperinflation.

Although these seem to be two distinct pathologies, patients who develop COPD often suffer with both, and these vary in proportion from patient to patient. There are still patients with COPD who have purer phenotypes; the 'blue bloater' with predominant chronic bronchitis, increased incidence of winter chest infections, cor pulmonale and type 2 respiratory failure, and the 'pink puffer' with predominant emphysema, cachexia, barrel-shaped chest and type 1 respiratory failure.

COPD is the fourth leading cause of death worldwide (and in the UK)1 and is likely to become the third between 2020 and 2030. It is the second most common reason patients present to the emergency department and accounts for 10% of all acute medical admissions. COPD currently costs the NHS approximately £1bn each year.2

There are almost 1m patients diagnosed with COPD, but there are at least another 2m people currently undiagnosed. These people have become known as the 'missing millions' after a report published by the British Lung Foundation.3

These missing millions are often symptomatic and of moderate to severe severity. Each year 50% of admissions to hospital with an acute exacerbation will be in patients for whom this is their first reported exacerbation.

Aetiology
In the UK, the main risk factor is cigarette smoking. COPD has the highest prevalence in areas of severe deprivation and high smoking prevalence. Those at the highest risk for developing COPD are patients who have smoked for at least 10 pack-years (one pack-year is 20 cigarettes smoked per day for one year). In this group 20-25% may develop the disease.

In fact in general practice a diagnosis of COPD should not be made without such a smoking history and in this case a referral to secondary care is encouraged.

Worldwide, the second most common cause is the burning of biomass fuels within confined environments. Genetic factors such as alpha-1 antitrypsin deficiency are responsible for early-onset emphysema but cases are rare.

Classification
The classification of COPD is according to post-bronchodilator FEV1. Post-bronchodilator FEV1 often causes confusion.

It means that if patients are using short-acting bronchodilators, the measurement is taken 15 minutes after the administration of 400 microgram salbutamol.

If patients are using long-acting bronchodilators (long-acting beta-agonists or long-acting antimuscarinic antagonists), they are encouraged to take them as prescribed in the morning, and do not need extra bronchodilation before their spirometry.

Severity grading of COPD according to NICE 20104
Stage FEV1/FVC Post-bronchodilator FEV1
Mild <0.7 >80%
Moderate <0.7 50–80%
Severe <0.7 30–50%
Very severe <0.7 <30%

Section 2: Making the diagnosis
The diagnosis of COPD is suspected on the basis of symptoms and signs, and is supported by spirometry. It is rare to diagnose COPD under the age of 35. The patient will be a smoker or ex-smoker and they usually present with cough, sputum production and shortness of breath. The increase in breathlessness in COPD tends to occur over months and years, punctuated by severe episodes of breathlessness known as exacerbations.

Spirometry is used to assist the diagnosis of airways obstruction (FEV1/FVC <0.7) and the severity of airflow limitation. FEV1 together with other investigations (BMI, MRC dyspnoea score and six-minute walk distance) can also help predict prognosis.

Caution is advised however, because although FEV1 defines the severity, it correlates poorly with symptoms. However, it is a predictor of mortality.

The diagnosis of an exacerbation is based on:

  • Worsening of breathlessness.
  • Increasing sputum volume.
  • Increasing sputum purulence.

The presence of at least two of these symptoms indicates an exacerbation.

Patients with a predominant emphysema phenotype will often fail to produce sputum even during an exacerbation; in these patients a history of accompanying wheeze, cough, sore throat and runny nose can help to make the diagnosis.

Spirometry
Most surgeries now possess suitable spirometers to assist with diagnosis and monitoring. A spirometer with real time readout of lung volume is crucial in determining true from spurious values.

This is particularly true for the forced vital capacity (FVC), where monitoring the blow until the volume reaches the plateau ensures the value is correct.

This is shown in the graph below.

Chest X-ray
In patients presenting for the first time with breathlessness, we recommend an X-ray to confirm the diagnosis and rule out other lung pathology. The chest X-ray will show features of hyperinflation, the presence of bullae and increased bronchovascular markings.

FBC
An FBC should be taken to exclude anaemia as the cause of breathlessness. Polycythaemia may exist in patients with chronic hypoxia; this is an indication for long-term oxygen therapy and in severe cases, venesection.

Oxygen saturation
Oxygen levels should be monitored at every review. Patients with an SaO2 <92% should be referred to an oxygen assessment service.

Normal and obstructive spirometry
Time-volume curve (not to scale). The subject with normal lungs can empty most of their volume in the first second. Patients with COPD have obstructive lung disease, which means they have difficulty with exhalation. Monitoring the curve during the manoeuvre identifies the FVC as the curve plateaus.

Section 3: Managing the condition
Like most long-term conditions COPD can be diagnosed and managed within primary care in the majority of cases. NICE has recently published not only guidelines for managing COPD but also standards of care that should be delivered to this population.5

The 13 NICE quality standards cover both primary and secondary care management in the stable and the exacerbating patient. They highlight the role of self-management plans (despite there being little evidence that they make an impact in COPD), the use of inhaled and oral treatments and the role of pulmonary rehabilitation.

The NICE guidelines for COPD were updated in 20104 and highlight the importance of the holistic approach to managing the condition. As well as inhaled therapies, pay particular attention to the following:

1. Activity Patients with COPD are often deconditioned and take part in little active exercise. Encouragement and access to pulmonary rehabilitation programmes for patients with an MRC score of three or more has been shown to be effective.

2. Nutrition Patients with a BMI <20kg/m2 are at a greater risk of hospital admission, and have a higher mortality rate compared with patients with a normal range BMI. BMI should be monitored at each review and dietetic interventions put in place if needed. There is an obesity paradox with COPD, with increasing survival in patients with BMI up to 30-35kg/m2.

3. Lifestyle Smoking cessation should be the first priority for smokers. Referral to cessation services and the use of adjuncts to reduce withdrawal symptoms are encouraged. Stopping smoking is the only intervention that can reduce the decline in FEV1.

Inhaled therapies
Inhaled therapies have been the mainstay of treatment for patients with COPD for more than a decade. They provide symptomatic relief, and long-acting bronchodilators can reduce exacerbation rates and hospitalisation.

NICE produced an easy to follow algorithm for prescribing. The guidelines are based not only on FEV1 (with FEV1 50% as a cut-off) but also on symptoms (see figure below).

Exacerbations
Exacerbations are normally associated with infection by a virus (rhinovirus, influenza and parainfluenza being the most common) or bacteria (Haemophilus influenzae, Streptococcus pneumoniae and Moraxella cattharalis). There is difficulty deciding which of these is the causative organism, due to the fact that these patients are often colonised with bacteria. Recent evidence points towards the possibility that it is the acquisition of new strains that triggers the exacerbation.

The mainstay of treatment in primary care focuses on the use of antibiotics and steroids. Our recommendations are that all exacerbating patients should receive at least one week of prednisolone at 30mg once daily; if they fail to improve during that week, another week at the same dose is recommended. Steroids should not be used beyond 14 days and there is no tailing off.

Steroids improve symptoms and lung function, and in a hospital environment, shorten hospital stay by two days.6

In most cases an antibiotic is also prescribed and should be based on local resistance patterns and cover the three bacterial species mentioned above. Randomised controlled studies of antibiotics versus placebo marginally favour the use of antibiotics.

Measurement of oxygen saturations is important and if they are 90% or below, referral to secondary care is recommended. NICE guidelines also help with this decision, and patients who have poor social support, peripheral oedema, rapid onset of symptoms and long-term oxygen therapy fall into the group that should be considered for admission.

Exacerbations that fail to resolve within two weeks may be caused by another comorbidity that accompanies COPD. These are commonly heart failure and pulmonary emboli. In two studies the incidence of thromboembolic disease in patients with features of a non-infectious exacerbation (no increase in sputum volume or change in colour) has been shown to be as high as 25%.

Other treatments should be considered, such as aminophylline and carbocysteine, but these have less of an evidence base. The use of long-term macrolide antibiotics has also been studied and has been shown to reduce exacerbations in a selective COPD population.

Oxygen therapy should be considered in patients with signs of cor pulmonale and in those with oxygen saturations below 92%. These should be referred to the local home oxygen assessment and review service.

Section 4: Prognosis
The prognosis for patients with COPD is very difficult to predict, with three-year survival still being as high as 50% for the very severe grade.

A useful tool known as the BODE index is often used and more accurately predicts three-year survival. This uses a combination of BMI, FEV1, MRC score and six-minute walk test.

In hospital, prognosis is even more difficult to predict. The use of non-invasive ventilation and the more widespread use of invasive ventilation for acute exacerbations has significantly improved overall survival to discharge as well as 90-day survival.

Palliative care services for patients with COPD have been historically limited. The provision of the Gold Standard Framework and increased funding for the provision of home palliative care has improved the situation, although such schemes are patchy in the UK.


COPD prognosis is difficult to predict (Photograph: SPL)

Follow-up
For patients suffering an acute exacerbation a follow-up appointment should be booked within two weeks (NICE quality standard).

Annual or six-monthly reviews should be scheduled, depending on the severity of the disease. It is often useful to combine these with the yearly flu vaccination. Pneumococcal vaccination should be offered to COPD patients.

Section 5: Case study
A 47-year-old woman presents to her GP surgery with increasing breathlessness. She was diagnosed with COPD four years ago; she is a current smoker of 30 cigarettes a day and experiences at least one exacerbation per year requiring steroids and antibiotics.

She presents for her annual review. It is obvious she is losing weight and her BMI is 18.6kg/m2. Her FEV1 is 48% predicted, oxygen saturations 94% and MRC dyspnoea score, three (she is having difficulty bringing her shopping home). Her current treatment is a salbutamol inhaler, beclometasone MDI and ipratropium bromide. She takes all of these on an as required basis.

Recurrent exacerbations
This patient is symptomatic with an MRC score of three and recurrent exacerbations. Interventions in activity, nutrition and lifestyle, as well as a change in pharmacotherapy, are vital.

She should be referred to her local pulmonary rehabilitation class and encouraged to exercise regularly. Her BMI is a cause for concern and this places her at high risk. A referral to the local dietitian is recommended. Smoking cessation would be the most beneficial intervention and she should be offered a referral to her local smoking cessation clinic.

Her inhaled treatment is inadequate for her stage of disease and symptoms and she is not using the inhalers appropriately. The most suitable therapy would be a combination of salbutamol and an inhaled corticosteroid and long-acting beta-agonist. Her inhaler technique should be checked and a self-management plan issued, describing her treatment and what to do if her breathlessness worsens.

A follow-up appointment at six to eight weeks should be scheduled to assess her response to the change in treatment.

Section 6: Evidence base
Clinical trials

This was a randomised, double-blind trial comparing a combination inhaler with placebo, salmeterol alone, or fluticasone propionate alone.

Compared with placebo, the combination regimen reduced the annual rate of exacerbations from 1.13 to 0.85 and improved health status and spirometric values (p <0.001 for="" all="" comparisons="" with="" placebo="" p="">

  • UPLIFT study. Tashkin DP, Celli B, Senn S et al for the UPLIFT Study Investigators. A 4-year trial of tiotropium in COPD. N Engl J Med 2008; 359: 1543-54.

In this study, the researchers investigated whether tiotropium attenuated the decline in FEV1 compared with placebo.

Mean absolute improvements in FEV1 in the tiotropium group were maintained throughout the trial (ranging from 87 to 103ml), compared with the placebo group (p <0.001).

At four years and 30 days, tiotropium was also found to be associated with a reduction in the risk of exacerbations, related hospitalisations and respiratory failure.

Contributed by Dr Simon Bourne, consultant in respiratory medicine, University Hospital Southampton NHS Foundation Trust.

Guidelines

Curriculum
This topic falls under section 15.8 of the GP curriculum Respiratory Problems.

Online

Click here to take a test on this article and claim a certificate on MIMS Learning

CPD IMPACT: EARN MORE CREDITS

These further action points may allow you to earn more credits by increasing the time spent and the impact achieved.

  • Hold a COPD event at the surgery with your known COPD patients, educating them on their disease.
  • Organise a campaign at your practice to screen people at risk of COPD.
  • Make an admission template for your COPD patients, which details the last three FEV1 results, O2 sats and MRC scales, and exacerbations, drugs and past history, in order to facilitate care in hospital.

References
1. Murray C, Lopez AD. Lancet 1997; 349: 1269-76.

2. Price LC, Lowe D, Hosker HSR et al. Thorax 2006; 61: 837-42.

3. British Lung Foundation. Invisible Lives. COPD - Finding The Missing Millions. 2007.

4. NICE. Management of COPD - in adults in primary and secondary care (partial update). CG101. NICE, London, 2010.

5. NICE. COPD quality standard. 2011

6. Davies L, Aungus R, Calverley P. Lancet 1999; 354(9177): 456-60.

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