TORONTO — A substantial proportion of patients with severe, refractory asthma are unable to become well controlled despite the availability of updated guidelines, even in subspecialty care, according to Dr. Amandeep S. Gill of the Medical College of Wisconsin, Milwaukee.
The National Asthma Education and Prevention Program's Guidelines for the Diagnosis and Management of Asthma have been updated periodically since they were first published in 1991, reflecting changes in evidence-based data since that time, with the latest revision being released in 2007.
However, little is known about the effect of the guidelines on the prevalence of severe refractory asthma. To assess the impact, a study was undertaken of 172 patients referred to subspecialty management programs in two Midwestern cities, comparing disease status at presentation and after 1 year of guideline-based care that included education and minimized barriers to care.
A total of 103 patients were seen in an asthma clinic at Case Western Reserve University, Cleveland, and 69 patients in a disease management program at the Medical College of Wisconsin, Milwaukee. Asthma morbidity was assessed retrospectively for the previous year, while patients were being managed in primary care, and prospectively for the subsequent year while they were receiving subspecialty care.
Controlled asthma was defined as:
▸ Symptoms no more than twice per week.
▸ Nocturnal symptoms fewer than two times per month.
▸ Short-acting bronchodilator use no more than twice per week.
▸ No interference with normal activities.
▸ Forced expiratory volume in 1 second (FEV1) at least 80% of predicted.
▸ No more than one exacerbation per year requiring oral corticosteroids.
In contrast, severe refractory asthma was classified as the requirement for high-dose inhaled corticosteroids and a long-acting β-agonist with or without oral steroids and/or omalizumab (step 5 or 6 pharmacotherapy in the guidelines).
The mean age at entry among patients from both cities was 48 years, and the mean duration of asthma was 17 years. More than three-quarters were female, and more than half were African American or Latino.
At presentation, 20% of patients from Cleveland and slightly more than 30% of patients from Milwaukee had severe refractory asthma, yet only 34% and 46%, respectively, were on appropriate medications for their level of disease severity. Only 54% and 62%, respectively, were able to demonstrate the proper use of a metered-dose inhaler.
After 1 year of subspecialty treatment, the numbers of urgent care and emergency department visits fell significantly in both groups, but many other disease characteristics did not improve significantly.
Overall, the percentage of patients whose asthma was well controlled improved from less than 10% to 20% after 1 year. However, 32% of patients still had severe persistent disease at 1 year, and half of those whose disease was not well controlled were receiving high-dose inhaled corticosteroids and a long-acting β-agonist.
Furthermore, at 1 year, 40% of patients from both cohorts were using the maximum available level of pharmacotherapy but could not achieve well-controlled status.
“Even when asthmatics are well educated in self-management techniques and have access to continuity of care and appropriate medications, more than three-fourths are unable to become well controlled,” Dr. Gill wrote.
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