Kowal Krzysztof, Bodzenta-Lukaszyk Anna, Zukowski Sebastian
Department of Allergology and Internal Medicine, Medical University of Bialystok, Poland.
J Asthma. 2009 Sep;46(7):692-8. doi: 10.1080/02770900903056187.
Bronchial asthma (A) is frequently diagnosed in patients with chronic cough. The study was conducted to determine whether an evaluation of fractional exhaled nitric oxide (FeNO) concentration can be used as a screening test for asthma in young adults with chronic cough (CCP).
The study was performed on 540 (mean age 26.5; range 18-45 years), nonsmoking young CCP. All patients had resting spirometry within normal limits and no abnormalities on chest radiographs. Skin prick tests with common aeroallergens, bronchial provocation challenge with histamine, and evaluation of FeNO concentration were performed in all patients. One hundred healthy, nonsmoking, nonatopic subjects were used as control subjects (HC).
Asthma (A) was diagnosed in 178 CCP (32.96%). Other frequent diagnoses included rhinitis/sinusitis (R) and gastroesophageal reflux (GERD). The median FeNO concentration in A (86 ppb; 95% CI 72 to 94,5 ppb) was significantly greater than in R (37 ppb; 95% CI 35,6 to 42,9 ppb; p < 0.0001), GERD (14,8 ppb; 95%CI 13.3 to 16.2 ppb; p < 0.0001), or in HC (13 ppb; 95%CI 11 to 15 ppb; p < 0.0001). Significant correlation was found between log(FeNO) and bronchial reactivity expressed as log(PC20) (r = -0.529; 95%CI -0.616 to -0.429; p < 0.0001), but even stronger correlation was demonstrated between log(FeNO) and peripheral blood eosinophilia (r = 0.757; 95%CI 0.717 to 0.792). Receiver Operator Characteristic (ROC) curve analysis revealed that CCP can be screened for A by measuring FeNO concentration. Using 40 ppb as a cut-off value for the FeNO concentration, the specificity 82.6% and sensitivity 88.3% can be achieved.
In clinical practice, assessment of FeNO concentration can be used as a screening test for asthma in young adults who have chronic cough.
支气管哮喘（A）在慢性咳嗽患者中经常被诊断出来。本研究旨在确定呼出一氧化氮分数（FeNO）浓度评估是否可作为慢性咳嗽的年轻成年人（CCP）哮喘的筛查试验。
对540名（平均年龄26.5岁；范围18 - 45岁）不吸烟的年轻CCP患者进行了研究。所有患者静息肺功能测定均在正常范围内，胸部X光片无异常。对所有患者进行了常见气传变应原的皮肤点刺试验、组胺支气管激发试验以及FeNO浓度评估。选取100名健康、不吸烟、非特应性受试者作为对照（HC）。
178名CCP患者（32.96%）被诊断为哮喘（A）。其他常见诊断包括鼻炎/鼻窦炎（R）和胃食管反流（GERD）。哮喘患者的FeNO浓度中位数（86 ppb；95%可信区间72至94.5 ppb）显著高于鼻炎/鼻窦炎患者（37 ppb；95%可信区间35.6至42.9 ppb；p < 0.0001）、胃食管反流患者（14.8 ppb；95%可信区间13.3至16.2 ppb；p < 0.0001）或健康对照（13 ppb；95%可信区间11至15 ppb；p < 0.0001）。发现log(FeNO)与以log(PC20)表示的支气管反应性之间存在显著相关性（r = -0.529；95%可信区间 -0.616至 -0.429；p < 0.0001），但log(FeNO)与外周血嗜酸性粒细胞增多之间的相关性更强（r = 0.757；95%可信区间0.717至0.792）。受试者操作特征（ROC）曲线分析显示，通过测量FeNO浓度可以对CCP患者进行哮喘筛查。以40 ppb作为FeNO浓度的截断值，特异性为82.6%，敏感性为88.3%。
在临床实践中，FeNO浓度评估可作为慢性咳嗽年轻成年人哮喘的筛查试验。
