Public Release: 

New study shows patients experience asthma variability, despite strict adherence to guidelines

Asthma variability leads to increases in resource utilization, direct and indirect costs


BOSTON, Nov. 15 - A study presented today at the 62nd Annual Meeting of the American College of Allergy, Asthma and Immunology shows that many patients with asthma continue to experience variability of disease control, despite strict adherence to treatment guidelines published by the National Heart, Lung and Blood Institute.(1) Variability in asthma control leads to continued disease symptoms and increased resource utilization, even when the disease is closely managed.

Although patients enrolled in the study experienced reductions in hospitalizations, emergency visits and clinic visits, researchers found important differences between those classified as having "high variability" and those with "low variability" of disease symptoms. Specifically:

  • Patients in the high variability group experienced greater overall direct and indirect costs, measured by number of emergency department visits, hospitalizations and days lost from work, school or daily activities of living. These patients also experienced more "sick visits," measured by unscheduled routine follow-up visits to primary care physicians, asthma clinics or urgent care facilities than those in the low variability group.(1)

  • Hospitalization, emergency room visits and clinic visit costs for treating asthma of high variability patients were estimated at $163 per patient per month, twice the cost for treating low variability patients ($81 per patient per month).

  • 74 percent of patients in the high variability group used rescue bronchodilators daily for more than half of the weeks of the observation period, compared to less than half (47 percent) of the patients in the low variability group.(1)

  • Asthma interrupted daily activity more often for patients in the high variability group. On average, high variability patients reported that asthma caused them to miss work, school, exercise or social activities 1.84 days per patient per month. Low variability patients reported missing activities 1.25 days per patient per month.(1)

    "Asthma is a highly variable disease, and patients may continue to suffer from symptoms as a result, despite adherence to practice guidelines," said Ileen Gilbert, MD, Professor of Medicine, Medical College of Wisconsin, lead investigator of the study. "We still need to know more about the underlying pathophysiology of the disease as well as more about environmental factors that trigger events and how to modify them in order to fully treat and reduce costs of this complicated disorder."

    Study Design and Methodology

    The analysis of the study, supported by AstraZeneca, assessed asthma variability in 125 inner-city patients (72 percent female; 68 percent minority [African- and Hispanic-American]; 80 percent treated by primary care physicians) in a period beginning six months prior to enrollment into an NHLBI guidelines-directed clinical and education intervention to minimize barriers to adherence, and ending six months following enrollment. Patients were stratified into two groups: those with high variability in asthma, and those with low variability. For purposes of the study, variability was defined as the number of fluctuations in NAEPP symptom class in the six-month post- intervention period. The 62 patients in the high variability group changed their NAEPP symptom class about once every other month, or more frequently. All other patients were classified as having symptoms in the low variability group.

    About Asthma Asthma is one of the most serious chronic medical conditions in the United States. In 2002, it was estimated that 20 million Americans have asthma. Of these, nearly 12 million Americans had an asthma attack or episode in the past year. Additionally, it is estimated that more than 30 million Americans, or about 10 percent of the U.S. population, have been diagnosed with asthma at some point in their lives.(2)

    Asthma is a reversible obstructive lung disease, caused by increased reaction of the airways to various stimuli, such as cigarette smoke, airborne molds, pollens, dust, animal dander, exercise, cold air, many household and industrial products, air pollutants, scents or simple stress. It is a chronic inflammatory condition that usually leads to breathing problems known as "episodes" - a series of events that result in narrowed airways - which is responsible for the difficulty in breathing with the familiar wheeze.(3)

    Although each person reacts differently to the factors that may trigger asthma, it can be a life-threatening disease if it is not properly managed. According to the American Lung Association, more than 4,200 Americans died from asthma in 2001.(2)


    About AstraZeneca

    AstraZeneca (NYSE: AZN) is a major international healthcare business engaged in the research, development, manufacture and marketing of prescription pharmaceuticals and the supply of healthcare services. It is one of the world's leading pharmaceutical companies with healthcare sales of over $18.8 billion and leading positions in sales of gastrointestinal, oncology, cardiovascular, neuroscience and respiratory products. In the United States, AstraZeneca is an $8.7 billion healthcare business with more than 11,000 employees. AstraZeneca is listed in the Dow Jones Sustainability Index (Global) as well as the FTSE4Good Index.

    For more information about AstraZeneca, please visit:

    (1) Gilbert IA, Perry SM, Olivares A, et al. Resource utilization associated with asthma variability in patients with mild, moderate, or severe persistent asthma adhering to national asthma education prevention program therapy guidelines. Abstract presented at 62nd Annual Meeting of the American College of Allergy, Asthma and Immunology, November 12, 2004

    (2) Trends in Asthma Morbidity and Mortality, American Lung Association, April 2004

    (3) Asthma in Adults Fact Sheet, American Lung Association, July 2003

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