Predicting the Diagnosis of Asthma

Study Summary

Despite the development of effective medications for treatment, asthma remains a significant contributor of morbidity, mortality, and financial hardship to patients with the disease. An estimated 300 million people worldwide have asthma, making it one of the most common chronic diseases in the world. Asthma accounts for 250,000 deaths per year worldwide, and 1.7 million emergency room visits per year in the United States. Cost of asthma in the United States was an estimated $12.7 billion dollars per year in 1998, and the prevalence is increasing. In 2002, there were 13.9 million outpatient asthma visits to private physician offices and hospital outpatient departments, and 484,000 asthma hospitalizations. Children 5-17 years of age missed 14.7 million school days, and adults missed 11.8 million work days due to asthma in 2002. There is no single diagnostic test or symptom that defines asthma. Asthma is a syndrome consisting of a constellation of symptoms that include wheeze, cough, shortness of breath, and chest tightness. The diagnosis of asthma takes into account history, physical examination findings, and objective measures of pulmonary function and markers of inflammation. In many cases the diagnosis is not in question, allowing for early recognition and appropriate treatment. In other cases, confounding factors makes the diagnosis both challenging and time consuming for the physician and the patient. According to the National Asthma Education and Prevention Program Expert Panel Report 2, asthma is defined as: "a chronic inflammatory disorder of the airways in which many cells and cellular elements play a role, in particular, mast cells, eosinophils, T lymphocytes, macrophages, neutrophils, and epithelial cells. In susceptible individuals, this inflammation causes recurrent episodes of wheezing, breathlessness, chest tightness, and coughing, particularly at night or in the early morning. These episodes are usually associated with widespread but variable airflow