Bronchiectasis, described as an “emerging global epidemic”, currently affects 350,000 to 500,000 people in the U.S and is increasing in prevalence.¹ It arises from chronic airway inflammation that is driven by persistent infection resulting in irreversible structural changes. It should not be confused with bronchitis which is often temporary. The ensuing self-sustaining cycle of infection and inflammation results in progressive lung disease² and is associated with significant morbidity and mortality. Individuals with bronchiectasis are approximately twice as likely to die as someone of the same age in the general population.³ Previously considered a rare disease, the increasing prevalence and impact of bronchiectasis, together with a history of poor clinical trial outcomes, are driving renewed research efforts and challenging established approaches.

Cough in Bronchiectasis has an Underappreciated Impact on Quality-of-life

Cough is not merely a symptom of bronchiectasis; it is one of the most distressing and persistent features of the disease. Up to 90% of patients experience daily cough, often with sputum production.⁴ For many, the impact extends well beyond physical discomfort. Frequent coughing disrupts sleep, provokes anxiety, and interferes with participation in everyday activities. Patients commonly report embarrassment when coughing in social or work environments and a persistent sense of loss of control, together contributing to a substantial and often underappreciated quality-of-life burden.⁵

Although cough in bronchiectasis is often described as productive, emerging evidence suggests there are multiple cough subtypes driven by distinct underlying mechanisms. Given the heterogeneous nature of bronchiectasis, identification of cough phenotypes may help guide treatment decisions and improve clinical outcomes.⁶

Cough as a Predictor of Exacerbations

Current guidelines use prior exacerbation history to predict future exacerbations and to qualify patients for treatment.^7,8 However, a recent study demonstrated that symptom burden is an independent risk factor for future exacerbations. Patients with high symptom burden but no or minimal previous exacerbations demonstrate a comparable risk to those with frequent exacerbations.⁹

In line with guidelines, clinical trials in bronchiectasis have focused on exacerbation frequency as the primary endpoint. However, inclusion of symptom-based endpoints, such as cough frequency may help capture clinically meaningful benefit.^10,11 For example, a recent post-hoc analysis of three randomized control trials investigating macrolide therapy demonstrated symptomatic improvements despite no meaningful reduction in exacerbation frequency. These findings also suggest that using symptom burden, rather than exacerbation history alone, to guide treatment eligibility may allow for earlier intervention and potentially prevent progression to a frequent exacerbation stage.⁹  

Measuring Cough in Bronchiectasis

Traditionally trials rely on patient-reported outcomes (PROs) to measure cough. PROs specifically validated for bronchiectasis and most often used in clinical trials include the Leicester cough questionnaire (LCQ), the Bronchiectasis Health Questionnaire (BHQ), quality of Life-Bronchiectasis (QoL-B). 

However, PROs often fail to capture the real-world frequency, severity, and timing of cough. Evidence suggests there is only a moderate relationship between subjective and objective assessments of cough in bronchiectasis.⁴ In addition, many trials use composite or non-cough specific PROs like BHQ and Qol-B, which limits the ability to draw meaningful conclusions about cough-related outcomes. Together, this highlights the importance of measuring cough using both subjective and objective approaches.

Wearable technologies, such as the The RESP® Biosensor, offer an opportunity to enhance cough assessment by objectively and continuously capturing intermittant symptoms. Generating more reliable and quantifiable data to complement to PROs, with widespread application for clinical trials.⁶

What next?

Ultimately, improved understanding and tracking of cough subtypes in bronchiectasis will help design better clinical trials. It will make it easier to select the right patients and enable the use of outcome measures that better reflect meaningful clinical benefit. The RESP® Biosensor’s ability to quantify cough positions it as a promising tool to support this approach.

References

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2. King P. Pathogenesis of bronchiectasis. Paediatr Respir Rev. 2011;12(2):104-110. doi:10.1016/j.prrv.2010.10.011
3. McCallion P, De Soyza A. Cough and bronchiectasis. Pulm Pharmacol Ther. 2017;47:77-83. doi:10.1016/j.pupt.2017.04.010
4. Spinou A, Lee KK, Sinha A, et al. Objective assessment of cough frequency in bronchiectasis. Lung. 2017;195(5):575-585. doi:10.1007/s00408-017-0038-x
5. Dudgeon EK, Crichton M, Chalmers JD. “The missing ingredient”: the patient perspective of health related quality of life in bronchiectasis: a qualitative study. BMC Pulm Med. 2018;18(1):81. Published 2018 May 22. doi:10.1186/s12890-018-0631-7
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8. Hill AT, Sullivan AL, Chalmers JD, et al. British Thoracic Society guideline for bronchiectasis in adults. Thorax. 2019;74(suppl 1):1-69. doi:10.1136/thoraxjnl-2018-212463
9. Sibila O, Stobo J, Perea L, et al. Symptoms, risk of future exacerbations, and response to long-term macrolide treatment in bronchiectasis: an observational study. Lancet Respir Med. 2025;13(10):911-920. doi:10.1016/S2213-2600(25)00160-2
10. Crichton ML, Aliberti S, Chalmers JD. A systematic review of pharmacotherapeutic clinical trial end-points for bronchiectasis in adults. Eur Respir Rev. 2019;28(151):180108. doi:10.1183/16000617.0108-2018
11. Metersky ML, Chalmers JD. Bronchiectasis insanity: doing the same thing over and over again and expecting different results? F1000Res. 2019;8:F1000 Faculty Rev-293. doi:10.12688/f1000research.17295.1