Nocturnal Cough and Sleep Quality to Assess Asthma Control and Predict Attacks

Abstract

Peter Tinschert,1,* Frank Rassouli,2,* Filipe Barata,3 Claudia Steurer-Stey,4,5 Elgar Fleisch,1,3 Milo Alan Puhan,4 Tobias Kowatsch,1,3 Martin Hugo Brutsche2 1Center for Digital Health Interventions, Institute of Technology Management, University of St. Gallen, St. Gallen, Switzerland; 2Lung Center, Cantonal Hospital 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: Peter TinschertCenter for Digital Health Interventions, Institute of Technology Management, University of St. Gallen, Dufourstrasse 40a, CH-9000, St. Gallen, SwitzerlandTel [phone]Email [email protected]: Objective markers for asthma, that can be measured without extra patient effort, could mitigate current shortcomings in asthma monitoring. We investigated whether smartphone-recorded nocturnal cough and sleep quality can be utilized for the detection of periods with uncontrolled asthma or meaningful changes in asthma control and for the prediction of asthma attacks.Methods: We analyzed questionnaire and sensor data of 79 adults with asthma. Data were collected in situ for 29 days by means of a smartphone. Sleep quality and nocturnal cough frequencies were measured every night with the Pittsburgh Sleep Quality Index and by manually annotating coughs from smartphone audio recordings. Primary endpoint was asthma control assessed with a weekly version of the Asthma Control Test. Secondary endpoint was self-reported asthma attacks.Results: Mixed-effects regression analyses showed that nocturnal cough and sleep quality were statistically significantly associated with asthma control on a between- and within-patient level (p < 0.05). Decision trees indicated that sleep quality was more useful for detecting weeks with uncontrolled asthma (balanced accuracy (BAC) 68% vs 61%; Δ sensitivity − 12%; Δ specificity − 2%), while nocturnal cough better detected weeks with asthma control deteriorations (BAC 71% vs 56%; Δ sensitivity 3%; Δ specificity − 34%). Cut-offs using both markers predicted asthma attacks up to five days ahead with BACs between 70% and 75% (sensitivities 75 - 88% and specificities 57 - 72%).Conclusion: Nocturnal cough and sleep quality have useful properties as markers for asthma control and seem to have prognostic value for the early detection of asthma attacks. Due to the limited study duration per patient and the pragmatic nature of the study, future research is needed to comprehensively evaluate and externally validate the performance of both biomarkers and their utility for asthma self-management.Keywords: asthma, digital biomarker, nocturnal cough, sleep quality, asthma control assessment, asthma attack prediction

Keywords

• asthma
• digital biomarker
• nocturnal cough
• sleep quality
• asthma control assessment
• asthma attack prediction