Cough and cough hypersensitivity should be recognised as a treatable trait of asthma and a potential indicator of asthma control, Australian and international respiratory specialists have proposed.
In a Personal View published the The Lancet Respiratory Medicine, a group of international clinicians inlcuding Professor Peter Gibson of the University of Newcastle, NSW, said it was surprising that to date cough had not had a key role in asthma assessment, given its link with greater disease severity and worse outcomes.
“Particularly in adults, cough or cough hypersensitivity meets all the criteria for a treatable trait, being clinically relevant, identifiable, measurable, and treatable,” they noted.
As such, the management of cough “should follow a treatable traits model of care, with attention to the treatment of bronchoconstriction, airway inflammation, mucus hypersensitivity and comorbidities,” they argued.
The authors have proposed models for cough assessment in both adults and children with asthma, following confirmation of the disease through the presence of reversible airflow obstruction or airway hyper-responsiveness.
Once diagnosis is confirmed, “assessment should then focus on: (1) core treatable trait assessment (type 2 inflammation and airflow obstruction); (2) differential diagnosis or identification of clinical conditions causing or affecting cough; and (3) assessment of cough”, according to the paper.
In adults, cough can be caused by a variety of clinical conditions, and use of trait identification markers could help to determine the presence of linked treatable factors to inform treatment choice, they noted.
For example, response to capsaicin challenge, cough counts and cough questionnaires could be used to determine the presence of cough reflex hypersensitivity, in which case appropriate treatment would include tiotropium, speech pathology intervention of neuromodulators.
Along the same lines, if a high-resolution chest CT identifies bronchiectasis, then physiotherapy, mucociliary clearance techniques, macrocodes, pulmonary rehabilitation and vaccination could help to address the cough, they said.
“A treatable traits approach makes sense because the expression of cough and cough hypersensitivity is heterogeneous in adults with asthma and the driving mechanisms might also be different,” they authors noted.
However, they also emphasised that key knowledge gaps remain in several areas related to the assessment and management of cough in asthma, which need to be addressed in future research to improve patient care.
“Discovering the patterns of cough in asthma, re-assessing cough as a symptom of asthma control or cough hypersensitivity, establishing the effects of current asthma treatments including type 2-directed biologics, and understanding the mechanisms of cough in asthma are factors that warrant close attention so that we can provide the most appropriate management of cough in asthma,” they stressed.
Read the paper in full here