Abstract
Asthma and COPD may overlap, especially in older people.BDT may be affected by the state of systemic in patients and cooperation. A advantage in IOS is to perform these measurements in a noninvasive and relatively effort independent during spontaneous normal tidal breathing. We used IOS before and after BDT to examine whether IOS parameter differ between patients with asthma and COPD? 661 participants (561 asthma, 100 COPD) were enrolled in the study. Included 442 males, ranging from 15 years to 98 years old. The impedance (Zrs) representing a complex airway resistance, which includes the real resistance (Rrs) and the imaginary reactance (Xrs), has also been determined. The frequency range of the signal was from 0 to 100 Hz, and we recorded R5–35 and X5-35. Rrs at 5 and 20 Hz represent the low (total resistance) and high (central resistance) frequency range. The parameters evaluated were R5, R20, R25, R35, X5, X20, X25, X35, resonant frequency (Fres) and peripheral resistance (Rp). In univariate logistic regression models, for COPD, X5 had an area under the curve (AUC) in the receiver operating characteristic (ROC) curve of 0.725, X25 an AUC of 0.724; and Fres showed an AUC of 0.730. For asthma, R5 had AUC of 0.710, X35 an AUC of 0.695; and Zrs showed an AUC of 0.721. IOS parameters had predictive effects if AUC is higher than 0.7. Therefore, X5, X20, X25, X35, Fres, Zrs and Rp correlated better with COPD. X5, X25 and Fres have clearly the best predictive value for COPD. For asthma, R5, X35 and Zrs have clearly the best predictive value. IOS combined BDT could be a useful diagnostic and differential diagnosis between asthma and COPD.
- Copyright ©the authors 2016
