Malerba Mario, Radaeli Alessandro, Olivini Alessia, Damiani Giovanni, Ragnoli Beatrice, Sorbello Valentina, Ricciardolo Fabio L M
Department of Internal Medicine, University of Brescia, Spedali Civili di Brescia, Brescia, Italy.
Respiration. 2016;91(3):206-14. doi: 10.1159/000443797. Epub 2016 Feb 9.
Forced expiratory flow at 25 and 75% of the pulmonary volume (FEF25-75%) might be considered as a marker of early airway obstruction. FEF25-75% impairment might suggest earlier asthma recognition in symptomatic subjects even in the absence of other abnormal spirometry values.
The study was designed in order to verify whether FEF25-75% impairment in a cohort of subjects with asthma-like symptoms could be associated with the risk of bronchial hyperresponsiveness (BHR) and with airway inflammation expressed as fractional exhaled nitric oxide (FeNO) and eosinophil counts in induced sputum.
Four hundred adults with a history of asthma-like symptoms (10.5% allergic) underwent spirometry, determination of BHR to methacholine (PD20FEV1), FeNO analysis and sputum induction. FEF25-75% <65% of predicted or <-1.64 z-score was considered abnormal.
All subjects had normal FVC, FEV1 and FEV1/FVC, while FEF25-75% was abnormal in 27.5% of them. FEF25-75% (z-score) was associated with PD20FEV1 (p < 0.001), FeNO (p < 0.001) and sputum eosinophils (p < 0.001). Patients with abnormal FEF25-75% showed higher levels of FeNO and eosinophils in induced sputum than did patients with normal FEF25-75% (p < 0.01 and p < 0.01, respectively). Subjects with abnormal FEF25-75% had an increased probability of being BHR positive (OR = 13.38; 95% CI: 6.7-26.7; p < 0.001).
Our data show that abnormal FEF25-75% might be considered an early marker of airflow limitation associated with eosinophilic inflammation and BHR in subjects with asthma-like symptoms, indicating a role for FEF25-75% as a predictive marker of newly diagnosed asthma.
肺容积25%和75%时的用力呼气流量（FEF25 - 75%）可被视为早期气道阻塞的一个标志物。FEF25 - 75%受损可能提示有症状的受试者即使在其他肺功能测定值无异常时也能更早地识别哮喘。
本研究旨在验证一组有哮喘样症状的受试者中FEF25 - 75%受损是否与支气管高反应性（BHR）风险以及以呼出一氧化氮分数（FeNO）和诱导痰中嗜酸性粒细胞计数表示的气道炎症相关。
400名有哮喘样症状病史的成年人（10.5%有过敏史）接受了肺功能测定、对乙酰甲胆碱的BHR测定（PD20FEV1）、FeNO分析和痰液诱导。FEF25 - 75% <预测值的65%或<-1.64 z评分被视为异常。
所有受试者的FVC、FEV1和FEV1/FVC均正常，而其中27.5%的受试者FEF25 - 75%异常。FEF25 - 75%（z评分）与PD20FEV1（p < 0.001）、FeNO（p < 0.001）和痰液嗜酸性粒细胞（p < 0.001）相关。FEF25 - 75%异常的患者诱导痰中的FeNO和嗜酸性粒细胞水平高于FEF25 - 75%正常的患者（分别为p < 0.01和p < 0.01）。FEF25 - 75%异常的受试者BHR呈阳性的概率增加（OR = 13.38；95% CI：6.7 - 26.7；p < 0.001）。
我们的数据表明，FEF25 - 75%异常可能被视为有哮喘样症状的受试者中与嗜酸性粒细胞炎症和BHR相关的气流受限的早期标志物，这表明FEF25 - 75%可作为新诊断哮喘的预测标志物。
