| Abstract: | Exercise provocation test was performed on a bicycle ergometer in 110 asthmatics, 15 allergic rhinitis patients, 10 patients with moderate chronic bronchitis and 22 healthy subjects. 87.5% (21/24) of atypical asthmatics revealed positive exercise induced asthma (EIA), with the overall positive rate of asthmatics being 90% (99/110). There was a close negative linear correlation between the maximal reduction rate in FEV1 induced by exercise (delta FEV1%) and the inhaled histamine dose needed to reduce FEV1 by 20% (PD20FEV1) (r = -0.59, P less than 0.01). None of the healthy subjects, one of 15 allergic rhinitis patients and one of 10 patients with moderate chronic bronchitis showed positive response to exercise test. In contrast, seven of 18 allergic rhinitis patients and all nine patients with moderate chronic bronchitis had positive response to histamine bronchial provocation test. Therefore, exercise provocation test is a reliable method for diagnosing EIA and detecting airway responsiveness and it may possess higher specificity than histamine provocation test in diagnosing bronchial asthma, particularly in atypical bronchial asthma. |
