"No single outcome measure can adequately assess asthma control," according to the official standards for clinical trials and practice with respect to the assessment of the disease, which appear in the July 1 issue of the American Journal of Respiratory and Critical Care Medicine. Created jointly by the American Thoracic Society and the European Respiratory Society, the standards aim to "provide a basis for a multi-component assessment of asthma by clinicians, researchers, and other relevant groups in the design, conduct, and evaluation of clinical trials, and in clinical practice."

The two organizations created a 24-person, multinational task force that conducted a narrative literature review of diary variables, physiologic measurements, composite scores, biomarkers, quality of life questionnaires, and indirect measures. Team members evaluated the measurement properties and strengths/weaknesses of outcome measures relevant to asthma control and exacerbations.

The resulting guidelines define three areas associated with the disease—control, severity, and exacerbations—and provide measurement recommendations. They are critical to the successful treatment and management of asthma because, said Helen Reddel, MD, PhD, in an official statement, “In the past, there has been no standard way of assessing asthma. This has led to a lot of confusion for doctors who are managing asthma, and, in research, it was difficult to compare the results of different studies.” Reddel is from the Woolcock Institute of Medical Research in Sydney, Australia, and co-chair of the international task force with D. Robin Taylor, MD, PhD, from the University of Otago in Dunedin, New Zealand.

Although they were unable to recommend any single measure of asthma control for use in clinical trials, the task force did develop a short list of standardized endpoints, which were divided up into essential, desirable, and optional.

“In the past, asthma severity was usually defined before a patient started asthma treatment, using measures that were almost identical to those used to assess asthma control. This was very confusing, and it meant that asthma severity could not be re-assessed once treatment had started,” explained Reddel.

Exacerbations (also called severe attacks) were defined as events requiring urgent treatment, such as corticosteroid tablets, over several days in order to prevent serious consequences.

Treatment recommendations include questions doctors can ask every asthma patient to learn more about that individual's short- and long-term asthma symptoms and management.

While a unified approach is beneficial, making the assessment of asthma control simpler will require additional investigation, according to the task force.

“More research is needed to understand more clearly how asthma control—and risks for asthma exacerbations—can be best assessed for the different types (ie, phenotypes) of asthma, which have different responses to therapy,” John Heffner, MD, past president of the ATS, confirmed in a release to the press. “The task force identified that studies will need to characterize the clinical features of study patients during enrolment to ‘type’ their asthma and then note patterns of treatment responses for each type. With enough information, accurate type-specific measures to assess asthma control will emerge that will guide physicians in adjusting therapy for each phenotype.”