The Relevance of Small Airway Dysfunction in Asthma with Nocturnal Symptoms

Abstract

Mustafa Abdo,1 Frederik Trinkmann,2,3 Anne-Marie Kirsten,4 Heike Biller,1 Frauke Pedersen,1,4 Benjamin Waschki,1 Erika Von Mutius,5 Matthias Kopp,6,7 Gesine Hansen,8 Klaus F Rabe,1 Thomas Bahmer,1,9,* Henrik Watz4,* On behalf of the ALLIANCE study group1LungenClinic Grosshansdorf, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Grosshansdorf, Germany; 2Department of Pneumology and Critical Care Medicine, Thoraxklinik, University of Heidelberg, Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), Heidelberg, Germany; 3Department of Biomedical Informatics, Heinrich-Lanz-Center, University Medical Center Mannheim, Heidelberg University, Heidelberg, Germany; 4Pulmonary Research Institute at the LungenClinic Grosshansdorf, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Grosshansdorf, Germany; 5Dr von Hauner Children’s Hospital, Ludwig Maximilians University of Munich, Comprehensive Pneumology Center Munich, German Center for Lung Research (DZL), and Institute of Asthma and Allergy Prevention, Helmholtz Centre, Both Munich, Germany; 6Department of Pediatric Respiratory Medicine, Inselspital, University Children’s Hospital of Bern, University of Bern, Bern, Switzerland; 7Division of Pediatric Pneumology & Allergology, University Hospital Schleswig-Holstein-Campus Luebeck, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Luebeck, Germany; 8Department of Paediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Biomedical Research in Endstage and Obstructive Lung Disease (BREATH), German Center for Lung Research (DZL), Hannover, Germany; 9University Hospital Schleswig-Holstein-Campus Kiel, department for Internal Medicine I, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Kiel, Germany*These authors contributed equally to this workCorrespondence: Mustafa AbdoLungenClinic Grosshansdorf, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Wöhrendamm 80, Grosshansdorf, 22927, GermanyTel [phone]Email [email protected]: Small airway dysfunction (SAD) is a frequent feature of asthma that has been linked to disease severity and poor symptom control. However, little is known about the role of SAD in nocturnal asthma.Objective: To study the association between the severity of SAD and frequency of nocturnal symptoms compared to conventional lung function testing.Methods: We assessed the frequency of self-reported nocturnal symptoms through the asthma control test. We studied the impact of nocturnal asthma using the Asthma Quality of Life Questionnaire (AQLQ) and the Multidimensional Fatigue Inventory (MFI-20). We assessed the lung function using spirometry, body plethysmography, impulse oscillometry, single and multiple inert gas washout and measured markers of T2-inflammation (blood and sputum eosinophils; fractional exhaled nitric oxide (FeNo)). We stratified the patients according to the presence and frequency of nocturnal asthma.Results: A total of 166 asthma patients were enrolled in the analysis. Eighty-seven patients (52%) reported to have nocturnal symptoms at least once in the last four weeks. The odds ratio of nocturnal asthma correlated with the severity of all non-spirometric measures of SAD, yet neither with airflow obstruction (FEV1 and FEV/FVC) nor with large airway resistance (R20). Patients with frequent nocturnal asthma (n = 29) had a numerical increase of T2 markers and more severe SAD, as indicated by all non-spirometric measures of SAD (all p-values < 0.05), worse overall asthma control, increased fatigue and reduced quality of life (all p-values < 0.01) compared to patients with infrequent nocturnal asthma (n = 58) or patients without nocturnal asthma (n = 79). We identified 63 patients without airflow obstruction, nearly 43% of them (n = 27) had nocturnal asthma. In this subgroup, only markers of air trapping and ventilation heterogeneity were significantly elevated and correlated with the frequency of nocturnal symptoms: LCI (Spearman’s coefficient = − 0.42, p < 0.001), RV% (− 0.32, p = 0.02).Conclusion: SAD is closely associated to asthma with nocturnal symptoms. Spirometry might underestimate the broad spectrum of distal lung function impairments in this population of patients.Keywords: small airway dysfunction, nocturnal asthma, ventilation heterogeneity, air trapping

Keywords

• small airway dysfunction
• nocturnal asthma
• ventilation heterogeneity
• air trapping