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Wednesday, November 3, 2010

New definitions for severe asthma recommended to WHO

We are highlighting a report in this month’s issue from the WHO consulting asthma experts that addresses the lack of universality in the diagnosis of severe asthma. Bousquet et al. present syncretic definitions of asthma severity, control, and exacerbations, and then further characterize severe asthma according to responsiveness to therapy.

Bousquet et al. propose uniformity of definitions of asthma severity based on 1) the components of asthma severity, which include intrinsic severity, clinical control, and attendant health and drug risks associated with the disease, 2) exacerbations, and 3) responsiveness to therapy. Current guidelines employ severity definitions that are tied to treatment response; however, the authors make a good case for the inclusion of severity assessment prior to therapy as well as during therapy, based on the more global issues associated with access to care and medicines in developing countries.

Bousquet et al. then propose a uniform definition of severe asthma as: “Uncontrolled asthma which can result in risk of frequent severe exacerbations (or death) and/or adverse reactions to medications and/or chronic morbidity (including impaired lung function or reduced lung growth in children).” Framing the definition in light of public health impact and challenges, they divide severe asthma into three groups: untreated severe, difficult-to-treat severe and treatment-resistant severe asthma. The last group comprises the current concept of refractory and steroid-resistant asthma and asthma that can be controlled only at the highest doses of treatment. Importantly, Bousquet et al. includes wheezing disorders in pre-school children in an effort to encourage research on differential clinical and phenotypic characteristics of early childhood asthma from adult asthma.

The authors conclude with comment on the global public health impact of severe asthma and the pressing need for interventions directed at reduction of healthcare utilization and optimization of quality of life. They also issue a call-to-arms for future asthma research programs to reduce the burden of severe childhood asthma and embrace a zero-tolerance philosophy for asthma-related death.

Dr. Stanley Szefler, Deputy Editor, contributes an editorial on the positive impact of Bousquet et al. recommendations.

We asked Dr. Bousquet to tell us about translating these recommendations into practice:

JACI: You have pointed out the difficulties associated with consistent asthma management in developing countries, such as access to and viability of appropriate medications. Will the difficulties faced by these countries make it hard for their practitioners to apply the uniform definitions you propose?

Jean Bousquet: A specific effort has been placed for developing countries. A large number of experts are from developing countries and the definition can be easily used in these countries. The definition also has a public health impact and it is hoped that this proposal will help all patients with asthma in the world (to) be able to get affordable asthma treatment.”

Do you have any questions for the authors, or comments about this study? We want to hear from you. Please feel free to post your own questions or comments. All questions and comments will be forwarded to the authors for a response.