The purpose of this study is to predict the diagnostic value of 5 different respiratory symptoms included in the Global Initiative for Asthma (GINA) questionnaire and to determine if bronchial hyperresponsiveness (BHR) by methacholine bronchial provocation test (MBPT) improves the predictive value of these respiratory symptoms.
A total of 680 subjects were enrolled in this study. They answered the GINA questionnaire and underwent MBPT.
Asthmatic patients revealed higher total symptom scores than non-asthmatics (mean 3.38 vs. 2.59; p =0.0001). Multivariate logistic regression analysis showed that wheezing and exercise induced dyspnea were questions significantly discriminated asthmatics (p<0.001). The cutoff value of total symptom score ≥2 was associated with the higher combination of sensitivity (86.3%) and specificity (20.4%). Receiver-operating characteristics curve (ROC) revealed the diagnostic accuracy of symptom associated diagnosis was high with an area under the curve of 0.610±0.029.Among the negative response to MBPT, the subjects had more than 2 symptom score was 32.5%.
Questionnaire assisted diagnosis of asthma is useful especially in situation of impossible use of MBPT. And, there are many symptomatic patients with negative MBPT, it will be needed consideration to management of these group.
This is the first trial to find an optimal cutoff value of positive methacholine bronchial provocation test. And negative methacholine bronchial provocation test with significant respiratory symptoms should be dealt with cautiously and further study will be needed.
Soyeon Lim, No Financial Disclosure Information; No Product/Research Disclosure Information