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:
"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)
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(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