Chronic obstructive pulmonary disease

In an environment where clinicians are increasingly conscious of the conflicting pressures of patients’ expectations and evidence obsessed purchasers, there is a temptation to regard guidelines as a potential straightjacket (and protocols and clinical pathways even more so)—or just irrelevant. But the recently published British Thoracic Society guidelines for managing chronic obstructive pulmonary disease should be welcomed.¹

Together with their international counterparts,^2–4 they signal a sea change in attitudes towards the management of this common disease, historically summed up at best as “treat it as if it were asthma” and at worst as neglectful nihilism. In addition, they set out a pragmatic definition of chronic obstructive pulmonary disease—a chronic slowly progressive disorder characterised by airways obstruction which does not change markedly over several months—which ought to see the end of the paralysing effect of trying to define similarities and differences between chronic obstructive pulmonary disease and asthma (are you a lumper or a splitter?). This should also liberate perceptions about the scope for management of the disease and lead to improvements in standards of care.

The British guidelines offer an important advance over previous ones. They move clearly in the direction of an evidence based rather than merely consensus based approach to drawing up guidelines, although arguably not far enough. These guidelines often make the distinction between a treatment for which evidence indicates that it will have no benefit from one for which evidence on efficacy is simply lacking. The approach is less rigorous than in a recent set of guidelines for the management of asthma in which categories of evidence and the strength of recommendations were clearly set out,⁵ but it is nevertheless a step towards more rational and effective management of a disease for which expensive drugs often achieve so little. Clinicians need to know (or be told?) when time honoured practice has been shown not to work.

This approach has also permitted a more balanced emphasis on the merits of non-pharmacological treatments. In particular, the role of smoking cessation rightly receives pride of place, and pulmonary rehabilitation is introduced. But here the American Thoracic Society standards² offer much more—notably a specific protocol for smoking cessation and a clearer outline and evaluation of what constitutes a pulmonary rehabilitation programme. If these approaches are to be encouraged rather than paid just lip service, then something more of the evidence in their favour as well as the “how to” is required in the guidelines, particularly for the non-specialist.

Given that inhaled drug treatment will remain an important issue for most clinicians treating chronic obstructive pulmonary disease, the guidelines could have helpfully given a more definitive approach to the vexed question of reversibility testing and its relevance to the effectiveness of long term treatment (as opposed to prognosis) using either inhaled bronchodilators or corticosteroids. This is particularly important given the justifiable emphasis which the guidelines place on obtaining spirometric values for diagnosing chronic obstructive pulmonary disease and assessing its severity. Here, an earnest attempt to present balanced evidence on a subject beset with contradictions and caveats has complicated the attempt to give clear directions. For bronchodilators, the problem is summed up: “a negative FEV₁ response does not preclude benefit.” This concurs with the position of the American Thoracic Society: “the absence of a response never justifies withholding bronchodilator therapy.“² This emphasis on acute reversibility tests as a guide to the potential benefits of long term treatment is the residue of an era when asthma and chronic obstructive pulmonary disease were lumped and not split. Perhaps such acute-chronic response relations ought to be studiously ignored. For inhaled steroids, the Australian and New Zealand guidelines advocate just such an approach.³ Given that the effectiveness or otherwise of inhaled corticosteroids and of long acting bronchodilators is the subject of current research—and that the guidelines cannot yet draw on definitive evidence about the role of these agents—then perhaps a revision should already be planned.

In the meantime, the value of these British guidelines should be emphasised and not diminished. They are well presented and brief and for general practitioners place appropriate emphasis on community based aspects of management. They represent an educational resource which is concise and excellently referenced: they should be required reading for trainees in general practice and medicine. Tucked away in the summary, we learn that the guidelines are intended to offer “a benchmark for current best practice.” But a statement of this goal is unfortunately missing from the foreword. Indeed, the aims and the intended applications for these guidelines, as well as a description of the methodological approach, ought to have been presented much more prominently, as was done to some extent by the European group.⁴ The guidelines deserve to be promoted as a credo and not just offered as an option.