Journal of Asthma and Allergy (Dec 2020)
Characteristics of Asthma-related Nocturnal Cough: A Potential New Digital Biomarker
Abstract
Frank Rassouli,1,* Peter Tinschert,2,* Filipe Barata,3 Claudia Steurer-Stey,4,5 Elgar Fleisch,2,3 Milo Alan Puhan,4 Florent Baty,1 Tobias Kowatsch,2,3 Martin Hugo Brutsche1 1Lung Center, Cantonal Hospital St. Gallen, St. Gallen, Switzerland; 2Center for Digital Health Interventions, Institute of Technology Management, University of St. Gallen, St. Gallen, Switzerland; 3Center for Digital Health Interventions, Department of Management, Technology, and Economics, ETH Zurich, Zurich, Switzerland; 4Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; 5mediX Group Practice Zurich, Zurich, Switzerland*These authors contributed equally to this workCorrespondence: Frank RassouliLung Center, Cantonal Hospital St. Gallen, Rorschacher Strasse 95, St. Gallen CH-9007, SwitzerlandTel +41 71 494 60 20Email [email protected]: The nature of nocturnal cough is largely unknown. It might be a valid marker for asthma control but very few studies characterized it as a basis for better defining its role and its use as clinical marker. This study investigated prevalence and characteristics of nocturnal cough in asthmatics over the course of four weeks.Methods: In two centers, 94 adult patients with physician-diagnosed asthma were recruited. Patient-reported outcomes and nocturnal sensor data were collected by a smartphone with a chat-based study app.Results: Patients coughed in 53% of 2212 nights (range: 0– 345 coughs/night). Median coughs per hour were 0 (IQR 0– 1). Nocturnal cough rates showed considerable inter-individual variance. The highest counts were measured in the first 30 min in bed (4.5-fold higher than rest of night). Eighty-six percent of coughs were part of a cough cluster. Clusters consisted of a median of two coughs (IQR 2– 4). Nocturnal cough was persistent within patient.Conclusion: To the best of the authors’ knowledge, this study is the first to describe prevalence and characteristics of nocturnal cough in asthma over a period of one month, demonstrating that it was a prevalent symptom with large variance between patients and high persistence within patients. Cough events in asthmatics were 4.5 times more frequent within the first 30 min in bed indicating a potential role of positional change, and not more frequent during the early morning hours. An important next step will investigate the association between nocturnal cough and asthma control.Keywords: asthma, nocturnal cough, passive monitoring
