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Diagnosing COPD

A diagnosis of COPD is often missed.

Dr David Bellamy shares his experience on how to identify early disease

1 Always consider COPD when a patient presents with respiratory symptoms. COPD is common, affecting 1-2 per cent of the population. A recent study from Copenhagen showed that over 25 per cent of previously fit, persistent smokers followed for 25 years developed COPD – far more than previously noted.

2 Ask more about persistent symptoms. A survey of 8,215 smokers followed over 35 years found that only 19 per cent with spirometrically defined COPD had been diagnosed with respiratory disease; only 47 per cent with severe spirometric COPD were diagnosed with lung disease (63 per cent of which had been diagnosed with asthma). GPs also need to review asthmatics on disease registers.

3 Review smokers with persistent cough. One of the most efficient methods of screening for COPD is to look for smokers over the age of 35 who have a persistent cough: 28 per cent will have airflow obstruction. Other common presenting symptoms are persistent breathlessness, sputum production and regular winter bronchitis.

4 Spirometry is still the gold standard to confirm diagnosis. It is essential that training

is provided to help staff ensure patients' blowing technique is correct and to interpret results accurately.

5 All international guidelines accept an FEV1 below 80 per cent predicted and an FEV1/FVC ratio below 0.7 as the criteria for diagnosis. QOF suggests patients to be included should have an FEV1 below 70 per cent predicted. This would exclude patients with early disease, who are most likely to benefit from stopping smoking.

6 Is it asthma or COPD? Bronchodilator reversibility testing to help differentiate asthma and COPD remains in the QOF criteria. It can be performed in a number of ways. These include standard testing with spirometry before and after a short-acting bronchodilator in the surgery, assessing spirometric response before and after a few weeks of bronchodilator treatment, and two weeks of twice-daily peak flow readings at home looking for diurnal variation, which may point to asthma.

7 Patients with COPD will have only small improvements in FEV1 with bronchodilators or steroids. This small change should not be seen as a reason not to give these therapies. Patients should be asked if a given inhaler improves dyspnoea or exercise ability. If there is a positive response the therapy should be continued.

8 Other measurements need to be considered. The level of breathlessness may not always correspond to FEV1: use the simple MRC dyspnoea scale to measure it. BMI may have an

influence. Attempt to establish how the symptoms affect lifestyle. Frequent exacerbations suggest more severe disease.

9 Exclude other illnesses. Lung cancer also occurs frequently in smokers with persistent cough or dyspnoea. A chest X-ray should be requested. Patients coughing up larger amounts of sputum may also have bronchiectasis, although often this can only be diagnosed by CT scan.

10 Treatment of COPD should always include smoking cessation. Drug therapy usually starts with short-acting bronchodilators. These may be ß-agonists or anticholinergics, and a clinical assessment of efficacy will determine which should be given. Long-acting bronchodilators may be added. Inhaled steroids are given to patients with FEV1 below 50 per cent predicted who are having exacerbations, to reduce exacerbation frequency and deterioration. Mucolytics also reduce exacerbations and make it easier for patients to cough up thick sputum. Pulmonary rehabilitation has a very important role in improving quality of life.

David Bellamy is a GP in Bournemouth, Dorset, and a member of the General Practice Airways Group, the British Thoracic Society and the British Lung Foundation. He was also a member of the NICE guideline development group on COPD

Competing interests Dr Bellamy has given talks for various pharmaceutical companies and has been sponsored to attend international respiratory meetings

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