To the Editors:
Enrigh tet al. 1 in the European Respiratory Monograph, promote office spirometry as the way forward in the routine assessment of asthma and chronic obstructive pulmonary disease (COPD), and in the early detection of COPD. They define office spirometry as ‘spirometry performed in the primary care setting’. There is an unwelcome ambiguity in their paper when it comes to both of these subjects, and the evidence they use to support their arguments is far from decisive. In the case of the early detection of COPD, the evidence seems to oppose their position.
My first concern is about their use of the term office spirometry, which seems to imply spirometry carried out by the consulting clinician. They say that spirometry with electronic spirometers is now faster than it was with traditional bellows spirometers. This latter suggestion is untrue, even using the 6 s manoeuvre, since the spirometry manoeuvre is independent of the type of spirometer used, the learning curve for the patient is the same and the instruction given by the operator is also identical. They believe that the main problem with office spirometry is in the quality of the instruction and supervision of the test by the clinician. I agree and think that this must be one of the main objections to spirometry being conducted by clinicians during routine consultations. They quote a primary care Dutch study in which the quality of the spirometry was unacceptably variable 2. Furthermore, they recommend certification for nurses and technologists carrying out spirometry in primary care. This hardly encourages the routine office use of spirometry by clinicians in their consultations.
The main argument put forward by Enright et al. 1 is for the use of spirometry in the early detection of COPD. They say that spirometry fulfils all the standard criteria for application of a medical test for screening. A fundamental criterion for any screening programme is the availability of a useful intervention for the patient who screens positive 3. The main reason to detect COPD in its early stages is to intervene with smoking cessation. Enright et al. 1 quote three papers in support of the role of early diagnosis of COPD in smoking cessation. None of these actually support their assertion.
The first by Risser et al. 4 is a trial of a complex intervention comparing education and a motivational intervention with education alone, in which spirometry was a just component of the motivational intervention. In the second paper Segnan et al. 5 actually conclude, “In no treatment group was the outcome significantly different from that for one-time counselling at the (p<0.05) level.” In the third paper, Gorecka et al. 6 demonstrated that the diagnosis of airflow limitation had no effect in improving smoking cessation overall, and only in a subanalysis could they show that it leads to an improvement in smoking cessation in those who have moderate or severe airflow limitation. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines acknowledge the uncertainty surrounding the benefits of community screening of COPD 7. While there is no argument that smokers should be sought and helped to quit smoking, there is no evidence that early diagnosis of COPD improves smoking cessation.
The promotion of early diagnosis of COPD has been gathering momentum despite the lack of evidence to justify it. Many papers are appearing which report the efforts of clinicians to diagnose COPD early. In the Differential Diagnosis between Asthma and COPD study, Buffels et al. 8 report that spirometry-based screening for COPD in primary care doubles the rate of diagnosis of COPD.
The impact on patients and services of a policy to diagnose chronic obstructive pulmonary disease early, which doubles the number of cases in the system, is likely to be expensive and will dilute the resources available for the management of symptomatic chronic obstructive pulmonary disease. It should not even be considered until there is at least some evidence to support it.
- © ERS Journals Ltd
