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Feasibility and Utility of a Smartphone Application-Based Longitudinal Cough Monitoring in Chronic Cough Patients in a Real-World Setting



This study evaluated the feasibility and utility of longitudinal cough frequency monitoring with the Hyfe Cough Tracker, a mobile application equipped with cough-counting artificial intelligence algorithms, in real-world patients with chronic cough.


Patients with chronic cough (> 8-week duration) were monitored continuously for cough frequency with the Hyfe app for at least one week. Cough was also evaluated using the Leicester Cough Questionnaire (LCQ) and daily cough severity scoring (0–10). The study analyzed adherence rate, the correlation between objective cough frequency and subjective scores, day-to-day variability, and patient experience.


Of 65 subjects consecutively recruited, 43 completed the study. The median cough monitoring duration was 13.9 days, with a median adherence of 91%. Study completion was associated with baseline cough severity, and the adherence rate was higher in younger subjects. Cross-sectional correlation analyses showed modest correlations between objective and subjective cough measures at the group level. However, in time series correlation analyses, correlations between objective and subjective measures widely varied across individuals. Cough frequency had greater day-to-day variability than daily cough severity scores in most subjects. A patient experience survey found that 70% of participants found the cough monitoring helpful, 86% considered it acceptable, and 84% felt it was easy to use.


Monitoring cough frequency longitudinally for at least one week may be feasible. The substantial day-to-day variability in objective cough frequency highlights the need for continuous monitoring. Grasping the implications of daily cough variability is crucial in both clinical practice and clinical trials.

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Authors and Affiliations



WJS is the full guarantor of this manuscript. SEL, PMS, KFC, and WJS contributed to the study conception and design and data interpretation. THK, JYO, JHL, and LJ have made contributions to the data acquisition. SEL and MR performed formal analysis. SEL and WJS drafted the first version of the manuscript. PMS, KFC, and WJS supervised and revised the manuscript. All authors approved this version of the manuscript for submission.

Corresponding author

Correspondence to Woo-Jung Song.

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Conflict of interests

SEL, THK, JYO, JHL, and WJS declare no related financial interests. MR, LJ, and PMS are employees of Hyfe Inc. KFC has received honoraria for participating in Advisory Board meetings of Roche, Merck, Novartis, GSK, Nocion, Shionogi, and Rickett-Beckinson and has also been renumerated for speaking engagements for Novartis and AZ. No authors received financial compensation for participation in this work.

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Lee, SE., Rudd, M., Kim, TH. et al. Feasibility and Utility of a Smartphone Application-Based Longitudinal Cough Monitoring in Chronic Cough Patients in a Real-World Setting. Lung 201, 555–564 (2023).

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