How often is the diagnosis bronchial asthma correct

The annual incidence of bronchial asthma starting in adulthood in the Swedish population varies between 0.1 and 0.5% depending on the definition used.1 In the city of Gothenburg, Sweden, the prevalence of asthma in 1994 was 5.5% in a population of about 450 000.2 Diagnosis of bronchial asthma is not always easy. Studies have shown underdiagnosed asthma in children,3 adolescents4 and adults,5 but little research has been done as concerns overdiagnosing asthma, in spite of the fact that symptoms similar to asthma can be seen in connection with other lung diseases such as chronic obstructive pulmonary disease (COPD), emphysema and chronic bronchitis. The same symptoms can also be seen in patients with cardiac failure, a pulmonary tumour or a hyperventilation syndrome. One group of patients with asthma-like symptoms, not mentioned above, has lately been focused upon. The disease has been called ‘functional breathing disorder’ (FBD).6,7 These patients have dyspnoea without any obstruction in their airways. Careful examinations can exclude other heart or lung diseases. As a consequence of the difficulties in diagnosing asthma, there is an obvious risk of arriving at a wrong diagnosis. The purpose of this study was to estimate the number of these patients.