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What you need to know about COPD

Respiratory physicians Dr Mahendran Chetty and Dr Graeme Currie answer GP Dr Pam Brown’s questions on reversibility testing, pneumonia risk with high-dose steroids and managing extrapulmonary manifestations

Respiratory physicians Dr Mahendran Chetty and Dr Graeme Currie answer GP Dr Pam Brown's questions on reversibility testing, pneumonia risk with high-dose steroids and managing extrapulmonary manifestations

1. What is the preferred method of reversibility testing?

41226253Reversibility testing to inhaled bronchodilators or steroids is not necessary if COPD is the probable diagnosis. In most cases, it has no benefit.

But reversibility testing should be considered if asthma is thought likely or if the response to COPD treatment is surprisingly good. If facilities and expertise are available, reversibility testing with a short-acting ß-agonist (400µg of inhaled or 2.5mg of nebulised salbutamol) is the preferred method. Alternatively, 30mg oral prednisolone may be given for two weeks. An improvement in forced expiratory volume in one second (FEV1) of above 400ml suggests that asthma – rather than COPD – may be the diagnosis.

2. The QOF forces us to categorise patients as having either COPD or asthma, yet many appear to have both. How common is a dual diagnosis and what clinical and spirometric findings will confirm this?

Nobody knows exactly how commonly COPD and asthma co-exist. The uncertain link and interaction between these two conditions is complex, as cigarette smoking in people with asthma can cause:

• the development of COPD

• neutrophilic airway inflammation

• reduced sensitivity to inhaled corticosteroids

• an accelerated decline in lung function

• difficult-to-control symptoms.

COPD can only be diagnosed when typical clinical features, along with a history of smoking, are present along with demonstrable airflow obstruction – FEV1/forced vital capacity (FVC) less than 0.7 – and an FEV1 of less than 80% predicted.

41226254Tests such as carbon monoxide transfer factor may be helpful in identifying COPD, as this value is normal – or elevated – in pure asthma and reduced in COPD.

Normal spirometry – or spirometry that returns to normal after treatment – indicates that clinically significant COPD is not present or that asthma may be the diagnosis. The table left shows clinical features which may help differentiate one condition from the other.

3. I sometimes see patients who simply can't provide a satisfactory blow on spirometry. How should I assess and treat them?

From our own personal experience, the vast majority of patients can perform a satisfactory ‘blow' when given sufficient time, instruction and patience. But in

those who are unable to perform forced expirations in the community, it is reasonable to consider referral to a hospital pulmonary function laboratory where more experienced technicians may be able to assist.

A small number of individuals may be unable to provide a satisfactory or reproducible spirometry result even on referral– for example frail or elderly patients or those with learning difficulties. If clinical and radiological features support a diagnosis of COPD, it is pragmatic and reasonable to start an empirical trial of treatment.

4. How frequently should repeat spirometry be carried out in those with confirmed COPD?

The British Thoracic Society recommends that patients with mild to moderate COPD (FEV1 30-80% predicted) are followed up at least annually and that those with severe disease (FEV1 less than 30% predicted) are seen at least twice per year. Every patient should be asked about smoking status, vaccination status, symptoms, exercise tolerance, frequency of exacerbations, and efficacy of medications. Inhaler technique should be assessed and FEV1, body mass index, oxygen saturation and MRC dyspnoea score should be measured.

5. How should we manage patients who have two or more infective exacerbations per year requiring antibiotics or steroids but whose FEV1 is more than 50% predicted and who therefore fail to meet the NICE criteria for using inhaled steroids?

NICE/British Thoracic Society guidelines recommend prescribing combination therapy with inhaled corticosteroids and long-acting ß-agonists (LABA) for patients with FEV1 less than 50% predicted with two or more exacerbations per year. This is mainly because inhaled steroids do not consistently confer benefit in those with milder (FEV1 more than 50% predicted) airflow obstruction.

However, as you quite rightly point out, many patients with FEV1 of more than 50% do, in real life, experience frequent exacerbations of COPD despite regular use of a long-acting bronchodilator.

In these patients, non-pharmacological approaches should be pursued with vigour – smoking cessation, nutritional advice, pulmonary rehabilitation, vaccination and encouragement of exercise.

It is also reasonable in these patients to prescribe both classes of available long-acting bronchodilator (long-acting anticholinergic and LABA).

But bear in mind that prescribing inhaled corticosteroids to those with FEV1 of more than 50% predicted with two or more exacerbations a year – usually in combination with a LABA – is currently an unlicensed indication.

6. What is the rationale for use of inhaled steroids and LABAs in COPD?

Many studies have shown that the combination of an inhaled steroid plus a LABA confers benefit in patients with COPD across a variety of endpoints. Currently, this combination (as Symbicort or Seretide) is usually given in a single fixed-dose inhaler device. As patients need only one inhaler, this may be associated with potential improved concordance.

A recent Cochrane review demonstrated that such combination therapy was more effective than LABAs as monotherapy in reducing COPD exacerbation rates, improving lung function and quality of life, although no significant impact upon mortality was found.

7. What is the evidence for use of tiotropium rather than ipratropium and should we switch patients currently on ipratropium?

Since ipratropium has a duration of action of three to six hours and maximal response after one to two hours, tiotropium once daily is likely to minimise patient inconvenience and confer benefit over a 24-hour period. Moreover, tiotropium acts mainly on M3 muscarinic receptors located in the airways to produce smooth-muscle relaxation whereas ipratropium acts non-selectively causing undesirable side-effects by blocking M2 receptors.

Head-to-head randomised controlled studies have generally favoured tiotropium (versus placebo and ipratropium) in terms of lung function, quality of life and exacerbations.

Given the superior clinical efficacy of tiotroptrium compared with ipratropium – and its once-daily dosing – we would recommend you consider switching patients over.

8. How large an increased pneumonia risk is there in those with COPD on high-dose inhaled steroids?

Recent studies have shown an increased risk of pneumonia in patients using inhaled corticosteroids in COPD. The TORCH study randomly compared high-dose fluticasone, fluticasone plus salmeterol, salmeterol alone and placebo.

Significantly higher rates of pneumonia were found in patients receiving fluticasone (12% with placebo, 13% with salmeterol, 18% with fluticasone and 20% with fluticasone plus salmeterol).

The INSPIRE trial compared a long-acting anticholinergic (tiotropium) with fluticasone plus salmeterol, with similar results (occurrence of pneumonia in 8% in the combination group versus 4% in tiotropium group, p=0.008).

Moreover, a Cochrane review of 10 studies found that, when compared with LABAs, combination therapy was more commonly associated with pneumonia (odds ratio 1.62; 95% CI 1.35-1.94).

9. What extrapulmonary manifestations of COPD should we assess and treat?

Extrapulmonary manifestations of COPD include:

• cachexia and weight loss

• skeletal muscle wasting

• normocytic normochromic anaemia

• secondary polycythaemia

• osteoporosis

• cor pulmonale

• anxiety and depression.

Many patients with COPD have anxiety and/or depression, which may well further impair quality of life and be associated with social isolation. Mental health status can be assessed with simple tools such as the hospital anxiety and depression scale (HADS).

If present, patients can be treated with conventional drugs, although care should be taken with benzodiazepines and other respiratory depressants.

10. When is referral for specialist opinion appropriate?

The British Thoracic Society recommends referral to a specialist if the following criteria are present:

• diagnostic uncertainty or symptoms disproportionate to the degree of lung function impairment

• haemoptysis or frequent chest infections

• a rapid decline in FEV1

• suspected severe COPD

• cor pulmonale

• hypoxic patients in whom home oxygen may be required

• bullous lung disease

• a young (under 40 years) age of onset

• lung transplantation or lung volume reduction surgery are possibilities.

11. Who should we refer for pulmonary rehabilitation and what are realistic improvements or outcomes?

Depending on local availability, all functionally impaired patients with symptoms of COPD – irrespective of age and smoking status – should be considered for pulmonary rehabilitation classes.

Regular attendance has been shown to improve exercise performance and health-related quality of life, and to reduce breathlessness. But there is generally no benefit in terms of lung function, long-term survival and number of hospital admissions.

Classes should ideally involve several components such as exercise training, education and psychological, behavioral and nutritional intervention tailored to an individual's needs.

Pulmonary rehabilitation is particularly helpful in breaking the vicious circle of worsening exertional breathlessness, reduced physical activity and reduced fitness and deconditioning.

12. The BNF recommends a one month trial of inhaled steroid and LABA and discontinuation if no improvement. In practice most patients are unlikely to have noticed any improvement in quality of life or reduction in exacerbations that quickly. How long a trial is realistic?

The current BNF (March 2009) does not state that these treatments should be discontinued after a failed one month therapeutic trial. Combination inhalers containing LABAs and inhaled steroids do confer benefit in terms of overall quality of life and reduction in exacerbation frequency. But this it may well take many months – perhaps up to a year – before such improvements are experienced for some individuals.

Dr Mahendran Chetty is a specialist registrar in respiratory medicine and Dr Graeme Currie is consultant respiratory physician at Aberdeen Royal Infirmary

Competing interests: None declared

COPD What I will do now What I will do now

Dr Pam Brown considers the responses to her questions
I think I'll continue to only use reversibility testing in smokers over 35 with typical COPD symptoms when I think there is a possibility of asthma.
The box on differentiating asthma from COPD is useful and I'll remember to ask about night-time symptoms and family history – both more suggestive of asthma – when considering a diagnosis of COPD.
I'd consider referring for lung function tests
if it's important to have accurate results – for consideration of long-term oxygen therapy, for example – and the patient is unable to produce
a good blow in practice.
I'll make sure we repeat spirometry at least annually in all our patients with COPD to assess disease deterioration.
After reviewing the evidence base, I think I'll be more likely to use tiotropium rather than ipratropium in future.
I think in our practice we're already very aware of nutritional consequences of COPD, but I'll be more alert for anxiety and depression.
I'll explore the availability of local pulmonary rehabilitation as it offers such great benefits.

Dr Pam Brown is a GP in Swansea

thps Asthma vs COPD

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