The Usefulness of FEF25–75 in Predicting Airway Hyperresponsiveness to Mannitol

Abstract

Youlim Kim,1,* Hyun Lee,2,* Sung Jun Chung,2,* Yoomi Yeo,2 Tai Sun Park,2 Dong Won Park,2 Kyung Hoon Min,3 Sang-Heon Kim,2 Tae-Hyung Kim,2 Jang Won Sohn,2 Ji-Yong Moon,2 Ho Joo Yoon2 1Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Konkuk University Hospital, School of Medicine, Konkuk University, Seoul, Korea; 2Department of Internal Medicine, College of Medicine, Hanyang University, Seoul, Korea; 3Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, Korea University Medical Center, Guro Hospital, Seoul, Korea*These authors contributed equally to this workCorrespondence: Ji-Yong MoonDepartment of Internal Medicine, Hanyang University Guri Hospital, Gyeongchun-ro 153, Guri-si, Gyeonggi-do, 11923, KoreaTel [phone]Fax [phone]Email [email protected] Joo YoonDivision of Pulmonary Medicine and Allergy, Department of Internal Medicine, Hanyang University College of Medicine, 222-1, Wangsimni-ro, Seongdong-gu, Seoul, 04763, KoreaTel [phone]Fax [phone]Email [email protected] and Objective: Despite the usefulness of airway hyperresponsiveness (AHR) testing in diagnosing and monitoring asthma, it is challenging to perform in a real-world setting. Forced expiratory flow between 25% and 75% of vital capacity (FEF25– 75), a pulmonary measurement that can be obtained easily during routine spirometry, represents the status of medium-sized and small airways. However, the performance of FEF25– 75 in predicting AHR has not been well elucidated. Therefore, we investigated whether FEF25– 75 can predict AHR to mannitol.Methods: We performed a retrospective cohort study of 428 patients who visited a single clinic due to cough, wheezing, or dyspnea. All patients underwent spirometry with a mannitol provocation test. We compared the area under the curve (AUC) of the percentage of the predicted values of FEF25– 75 (FEF25– 75 %pred) with that of forced expiratory volume in 1 second (FEV1%pred), FEV1/forced vital capacity (FVC), and FEF25– 75/ FVC for predicting AHR.Results: The rate of AHR to mannitol was 20.3%. In the overall study population, the AUC of FEF25– 75 %pred for predicting AHR (0.772; 95% confidence interval [CI], 0.729– 0.811) was significantly higher than that of FEV1%pred (0.666; 95% CI, 0.619– 0.710; p < 0.001), FEV1/FVC (0.741; 95% CI, 0.697– 0.782; p = 0.047), and FEF25– 75/FVC (0.741, 95% CI = 0.696– 0.782, p = 0.046). The sensitivity, specificity, positive predictive value, and negative predictive value of FEF25– 75 %pred < 81% for predicting AHR in the overall study population were 77.0% (95% CI = 66.8– 85.4%), 63.9% (95% CI = 58.6– 69.0), 35.3%, and 91.6%, respectively. When we restricted the study group to subjects with normal lung function, the results were similar.Conclusion: Our results indicate that FEF25– 75 %pred can be used as a surrogate for predicting AHR in patients with respiratory symptoms.Keywords: forced expiratory flow between 25% and 75% of vital capacity, mannitol, bronchial hyperresponsiveness

Keywords

• forced expiratory flow between 25% and 75% of vital capacity
• mannitol
• bronchial hyperresponsiveness