We investigated the basis on which respiratory physicians establish a diagnosis of
asthma in clinical practice. A questionnaire survey was conducted on physicians in charge of 1,600
asthma patients receiving outpatient treatment at the Hokkaido University General Hospital or its affiliated hospitals or clinics. The bases for diagnosis were ranked as follows: 1) recurrent
paroxysmal dyspnea or symptoms such as
wheezing and
cough (86%); 2) detection of
wheezing on auscultation (78%); 3) improvement in symptoms or auscultation findings after using
bronchodilators (56%); 4) improvement in symptoms or auscultation findings after using inhaled
corticosteroids (55%); 5) diagnosis of
asthma by another physician (46%); and 6) spirometry findings (31%). The performance rates of each examination were as follows. Spirometry at initial visit, 47%; sputum eosinophils, 25%; improvements in FEV1 measured after inhalation of
bronchodilator or
after treatment as
asthma, 12%; measurements of airway responsiveness, 5% and variability in peak expiratory flow, 2%.
Asthma is often diagnosed by respiratory physicians based on symptoms, physical examinations and improvement in symptoms or physical findings
after treatment for
asthma in medical practice. The performance rates of tests used to diagnose
asthma were low.