International European Respiratory Society/American Thoracic Society guidelines on severe asthma

From the authors:

We thank J. Bousquet and colleagues for their concerns regarding exclusion of “untreated asthma” as a form of severe asthma, with respect to the recently published international European Respiratory Society (ERS)/American Thoracic Society (ATS) guidelines on severe asthma [1].

We do recognise this category of untreated asthma and agree that untreated asthma may result in serious exacerbations of disease and death, an issue that is not confined to developing countries alone. Indeed, everywhere in the world, untreated asthma can result from lack of access to medical care but can also result not only from nonadherence to therapy or of inadequately treated asthma. As emphasised in the ERS/ATS guideline definitions, these issues should to be addressed before consideration of the diagnosis of severe asthma. As mentioned by the correspondents, the recent report of the UK National Review of Asthma Deaths pointed to under-treatment or lack of controller treatment, from nonadherence or inadequately treated asthma, which represents degrees of “untreated” asthma, evident in a country where everyone has access to medical care. The approach here is to identify the asthmatics who are at risk of dying from asthma and make sure that their asthma is indeed properly diagnosed and categorised, and treated appropriately. As our correspondents are aware, this is no mean task and is even near-impossible in developing countries where the healthcare infrastructure is not as well developed or funded.

We are fully aware of the World Health Organization (WHO) consultation document [2], not least, because several members of our ERS/ATS guideline task force have been involved in it. Untreated asthma could not be included within our severe asthma definition because our definition requires that patients receive or have received “appropriate/guidelines-based” therapy for asthma. While we agree that untreated or under-treated asthma predisposes a subgroup of these patients to severe and life-threatening exacerbations, we also believe that the introduction of even modest doses of corticosteroids will dramatically decrease their risk of severe asthma exacerbations. Thus, the ERS/ATS guidelines define severe asthma as “asthma that requires treatment with high dose inhaled corticosteroids plus a second controller (and/or systemic corticosteroids) to prevent it from becoming ‘uncontrolled’ or which remains ‘uncontrolled’ despite this therapy”. These patients represent a poorly understood and poorly therapy-responsive population that is distinct from under-treated or untreated asthma.

The WHO consultation document recognised three categories of asthma that were considered severe on the basis of symptoms, control of asthma and risks, without consideration of the therapy taken by the patient. These categories are 1) untreated severe asthma, 2) difficult-to-treat severe asthma and 3) treatment-resistant severe asthma, with which we are in full agreement. We agree that, from the global standpoint, untreated severe asthma needs to be recognised as it is a problem that should be remediable through the provision of affordable anti-inflammatory inhaler therapies and improved care of asthma in general. We are supportive of this categorisation of severe asthma within the WHO definition.

The ERS/ATS definition identifies the group of patients encompassed by categories 1 and 3. We see the ERS/ATS guidelines as entirely complementary to the WHO document focusing on these two categories, particularly treatment-resistant severe asthma, where approaches to phenotyping and targeted novel therapies will be needed, once the issue of untreated asthma at the individual level has been excluded.

We thank J. Bousquet and colleagues for giving us the opportunity to clarify these issues.

• Received July 1, 2014.
• Accepted July 3, 2014.

• ©ERS 2014