Bernstein Jonathan A, Davis Ben, Alvarez-Puebla María J, Nguyen Douglas, Levin Linda, Olaguibel Jose M
University of Cincinnati College of Medicine, Department of Internal Medicine, Division of Immunology/Allergy Section, Ohio, USA.
J Asthma. 2009 Nov;46(9):955-60. doi: 10.3109/02770900903265804.
To determine the general utility of clinical (Asthma Control Test) and physiologic (forced expiratory volume in the first second of exhalation [FEV(1)] and fractionated exhaled nitric oxide level [FeNO]) parameters for characterizing asthma patients.
Two cross-sectional independent studies simultaneously enrolled 100 patients in the US and 109 patients in Spain > or = 18 years of age with a physician-diagnosis of asthma and confirmed by a > or = 12% improvement in FEV(1) after bronchodilators or the presence of airway hyperresponsiveness, a central feature of asthma, as measured by methacholine challenge (PC(20) < 10 mg/mL). There was no restriction on asthma severity or treatment. Patients were excluded if they had a diagnosis of chronic obstructive pulmonary disease and/or were current cigarette smokers. Statistical analyses were performed to compare ACT, FeNO, and spirometry within and between sites.
Population characteristics revealed significant differences in distributions of age, percent-predicted FEV(1) (%FEV(1)), FeNO, inhaled corticosteroid usage, and atopy between the two populations. The Spain site enrolled younger patients with milder asthma, based on higher %FEV(1) values and less frequent treatment with inhaled corticosteroids. At each site, mean FeNO levels decreased as asthma control categories increased, and means were lower in the US. There was a negative correlation between ACT and FeNO that was statistically significant for Spain patients not treated with inhaled corticosteroids.
The results of this study support the use of FeNO as an adjunctive tool for assessing asthma primarily in mild inhaled corticosteroid (ICS)-naïve asthma patients. The lack of correlation of ACT with FeNO in this and other studies across the entire population appears to reflect the heterogeneity of asthma patients who have an admixture of asthma severity and treatment regimens making it very difficult to appreciate the nuances of sensitive tests like FeNO.
确定临床指标（哮喘控制测试）和生理指标（第一秒用力呼气量[FEV(1)]以及呼出一氧化氮分级水平[FeNO]）在哮喘患者特征描述中的总体效用。
两项横断面独立研究同时在美国纳入了100名年龄≥18岁、经医生诊断为哮喘且经支气管扩张剂治疗后FEV(1)改善≥12%或存在气道高反应性（哮喘的一个核心特征，通过乙酰甲胆碱激发试验测定[PC(20)<10mg/mL]）予以确诊的患者，以及在西班牙纳入了109名此类患者。对哮喘严重程度或治疗方法没有限制。如果患者被诊断患有慢性阻塞性肺疾病和/或当前为吸烟者，则将其排除。进行统计分析以比较各研究点内部和之间的哮喘控制测试（ACT）、FeNO和肺量计测量结果。
人群特征显示，这两个人群在年龄分布、预测FEV(1)百分比（%FEV(1)）、FeNO、吸入性糖皮质激素使用情况和特应性方面存在显著差异。基于更高的%FEV(1)值和吸入性糖皮质激素治疗频率较低，西班牙研究点纳入了哮喘病情较轻的年轻患者。在每个研究点，平均FeNO水平随着哮喘控制类别增加而降低，且美国的平均水平更低。ACT与FeNO之间存在负相关，这在未接受吸入性糖皮质激素治疗的西班牙患者中具有统计学意义。
本研究结果支持将FeNO用作主要评估轻度未使用吸入性糖皮质激素（ICS）哮喘患者哮喘病情的辅助工具。在本研究以及其他针对整个人群的研究中，ACT与FeNO缺乏相关性，这似乎反映了哮喘患者的异质性，他们的哮喘严重程度和治疗方案各不相同，使得很难理解像FeNO这样的敏感测试的细微差别。
