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Spirometry, COPD and the new contract

Spirometry is vital in COPD and practices without access to it

will be at a great disadvantage, says Dr Peter Stott

When the GMS2 contract1 comes into force in April it will ultimately provide practices with the necessary financial resources to manage chronic respiratory conditions more effectively. Great emphasis will be placed upon distinguishing between asthma and chronic obstructive pulmonary disease (COPD). While it is quite possible to confuse the two on symptoms alone, their management is significantly different. Asthma, of course, causes reversible airways obstruction whereas COPD results in irreversible obstruction. The two conditions can be distinguished by spirometry and the use of a reversibility test to diagnose COPD will earn the practice quality points.

Indicator targets for COPD

To qualify for the COPD quality initiative (QI) payments practices will need to provide evidence of attaining the following targets for initial diagnosis and ongoing management.

 · Initial diagnosis COPD 1. The practice can produce a register of patients with COPD. Five points equivalent to £375 for an average practice (ie three partners, 5,500 patients) in 2004/5.

COPD 2. The percentage of patients where diagnosis has been confirmed by spirometry including reversibility testing for newly-diagnosed patients (ie, after April 1, 2003). Minimum threshold 25 per cent. Maximum threshold 90 per cent earns five points (£375 for an average practice).

COPD 3. The percentage of all patients with COPD where diagnosis has been confirmed by spirometry including reversibility testing: minimum threshold 25 per cent: Maximum threshold 90 per cent earns five points.

 · Ongoing management COPD 6. The percentage of patients with COPD with a record of FEV1 in the previous 27 months. Minimum threshold 25 per cent. Maximum threshold 90 per cent earns six points (£450 for an average practice).

These are not the only points available for COPD, but they are the only ones linked to spirometry and bring the total quality income available from use of spirometry to £1,200 for an average weighted practice in 2004/5. In 2005/6 this will rise to £1,920 in line with the gross investment guarantee.

Typical spirometry results in COPD

The BTS2 and GOLD3 guidelines suggest that in COPD, lung function is usually taken as abnormal if:

 · FEV1 is less than 80 per cent of predicted normal

 · FVC is less than 80 per cent of predicted normal

 · FEV1/FVC ratio is less than 75 per cent.

Peak expiratory flow (PEF), though useful in asthma, provides little information in COPD. In COPD, PEF is often normal but expiration as measured by FEV1 is much slower. FEV1 is therefore the most important measure of disease severity in COPD. However, it is non-specific and will also be reduced in asthma and in restrictive lung disease.

 · FEV1 >80 per cent = normal lung capacity

 · FEV1 60-79 per cent = mild COPD

 · FEV1 40-59 per cent = moderate COPD

 · FEV1 <40 per="" cent="severe">

The contract sets the COPD diagnostic threshold for FEV1 at 70 per cent 'because a significant number of patients with an FEV1 less than 80 per cent of predicted may have minimal symptoms and the use of 70 per cent enables clinicians to concentrate on symptomatic COPD'.

But GMS2 states other criteria must also be met before COPD is diagnosed. The rationale (COPD 2.1) states that COPD should only be diagnosed if: the patient has an FEV1 of less than 70 per cent of predicted normal; and has an FEV1/FVC ratio of less than 70 per cent; and there is a less than 15 per cent response to a reversibility test.

The quality initiative recognises that asthma and COPD commonly co-exist and that many patients with asthma who smoke will have a positive response to reversibility testing despite having COPD. However, it states that these patients should be managed as for asthma.

How to test for reversibility

The British Thoracic Society COPD guidelines suggest reversibility should be documented by spirometry reading before and after the following alternatives:

la course of oral prednisolone 30mg/day taken for two weeks

linhaled beclomethasone (or equivalent) at least 500µg twice daily for six weeks

lbefore and after an adequate dose of inhaled bronchodilator given by nebulisation (salbutamol 2.5-5.0mg, terbutaline 5-10mg, ipatropium 500µg) alone or in combination.

The pre-reversibility test should obviously be done when patients are well and when they have not taken bronchodilators.

A positive test which is significantly greater than the natural variability is a =200ml and =15 per cent increase in FEV1 from baseline. An increase of more than 500ml is very suggestive of asthma. A negative response exists when the change is less than this.

Spirometry as an enhanced service

Spirometers cost around £1,000 (the cheapest handheld devices cost around £250) and only a minority of practices possess one. Reversibility testing is going to become so important, however, that we will all need to have access. Practices that do have a spirometer may like to consider offering this as a service to those who do not. This might be arranged via the PCT as a locally organised, enhanced service.

Section 2.13 (II) and 2.15 (iv) of GMS2 describes this category of enhanced services as 'services which are not provided through essential or enhanced services which might include more specialised services undertaken by GPs or nurses with special interests and allied health professionals and other services at the primary-secondary care interface'. They may also include services addressing specific local health needs or requirements, and innovative services that are being piloted and evaluated.

Interpreting spirometry results

FEV1 varies with age, sex and height so it is important to use the correct reference value. Standard tables and 'slide rules' are available and the values published by the European Respiratory Society are most often used4.

Without wishing to be elitist, ageist or sexist: tall young men have higher values of FEV1 than do short, old women. A 42-year-old man, 1.95m in height, would be expected to have an FEV1 of 4.59 litres whereas a 66-year-old woman with a height of 1.5m would be expected to have an FEV1 of 1.6 litres. This general pattern of distribution is seen with all lung function values ­ FVC, FEV1 and PEF. Spirometry also provides other information that can give an indication of the state of lung function.

 · Forced expiratory time (FET) in health is normally between three and four seconds, ie the time for a complete exhalation. In airways disease it is often greater than six seconds due to air trapping and loss of elasticity in the airways.

 · Forced vital capacity (FVC) is that volume of air that can be completely exhaled. This value is unaffected by airways obstruction. In health it is generally between 3,000ml and 6,000ml depending again on sex, age and height. In asthma it is usually normal. In COPD it is usually only slightly reduced. In restrictive airways disease (such as pulmonary fibrosis or pneumoconiosis) FVC is reduced according to the severity of the disease.

 · FEV1/FVC ratio. This value represents the proportion of the total lung volume that can be exhaled in one second. In young people, it is usually 90 per cent or more. But it gets less as people age. Anything above 70 per cent is usually taken as normal. In patients with obstructive airways disease (asthma and COPD) it will usually be lower than 70 per cent.

Spirometry is central to the diagnosis and ongoing management of COPD and practices that do not have access to this service will find themselves at a great disadvantage.

Reversibility testing

Bronchodilator Dose FEV1 before and after

Salbutamol 2.5-5mg (nebuliser) 15 minutes

200-400µg

(large volume spacer)

Terbutaline 5-10mg (nebuliser) 15 minutes

500µg

(large volume spacer)

Ipatropium bromide 500µg (nebuliser) 30 minutes

160µg

(large volume spacer)

Steroid Dose FEV1 before and after

Prednisolone 30mg/day (oral) Two weeks

Beclomethasone 1,000µg/day Six weeks

dipropionate/budesonide (large volume spacer)

Fluticasone propionate 500µg/day Six weeks

(large volume spacer)

From: British Thoracic Society COPD Consortium 2000.

Spirometry in Practice.London: Direct Publishing Solutions, 2000.

Interpreting spirometry results (Normal values ­ based on European Respiratory Society guidance) - See December 15th 2003 Issue of Pulse, pages 34-35

References

1 NHS Confederation/BMA. 2003.

New GMS Contract 2003

2 British Thoracic Society. COPD Guidelines Summary 1997.

Thorax 52; (suppl 5):s1-s32

3 Global strategy for the diagnosis, management and prevention of chronic obstructive lung disease 2003. National Institutes for Health. www.goldcopd.com

4 European Respiratory Society standardised lung function testing.

Eur Respir J 1993;6 (suppl 16):s5-s40

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