Journal: Journal of Asthma and Allergy

Abbreviation

Publisher

Dove Medical Press

Journal Volumes

ISSN

1178-6965

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20202
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Publications 1 - 2 of 2
  • Characteristics of asthma-related nocturnal cough – a potential new digital biomarker
    Item type: Journal Article
    Rassouli, Frank; Tinschert, Peter; Barata, Filipe; et al. (2020)
    Journal of Asthma and Allergy
    Introduction: 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 4 weeks. Methods: In 2 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 minutes in bed (4.5-fold higher than rest of night). 86% of coughs were part of a cough cluster. Clusters consisted of a median of 2 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 minutes of bedtime 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.
  • Nocturnal cough and sleep quality to assess asthma control and predict attacks
    Item type: Journal Article
    Tinschert, Peter; Rassouli, Frank; Barata, Filipe; et al. (2020)
    Journal of Asthma and Allergy
    Introduction: 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 were 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 < .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.
Publications 1 - 2 of 2