The "vicious circle" of chronic cough: the patient experience - qualitative synthesis

Cough Reflex Hypersensitivity as a Key Treatable Trait

Cough reflex hypersensitivity is emerging as a key treatable trait in chronic cough and other cough-associated respiratory conditions. This review examines the neurological basis of cough, highlighting the complex interplay between peripheral and central mechanisms. The concept of cough hypersensitivity aims to address unmet clinical needs by recognizing chronic cough as a distinct disorder rather than merely a symptom. Evidence from clinical trials supports cough hypersensitivity as a treatable trait in chronic cough, with opiates, gabapentinoids, and novel P2X3 antagonists showing efficacy. Cough hypersensitivity is also relevant in conditions presenting with persistent cough, such as asthma, bronchiectasis, and idiopathic pulmonary fibrosis, though more research is needed. Recognizing cough reflex hypersensitivity as a treatable trait offers new avenues for management, particularly for patients with persistent cough despite etiology-targeted therapies. We propose redefining chronic cough as a distinct disease entity in which cough hypersensitivity is a common feature and key therapeutic target, potentially leading to better patient care and the development of novel therapies.

Current opinion in refractory and/or unexplained chronic cough

PURPOSE OF REVIEW

Otolaryngologists are vital to successfully managing chronic cough in adults. This review presents updates regarding rapidly evolving concepts in chronic cough.

RECENT FINDINGS

Significant growth is occurring in chronic cough research, strengthening the evidence of its major psychosocial impacts. Elucidation of the neural underpinnings of normal and abnormal cough within both the peripheral and central nervous systems highlight the previously underappreciated complexity of cough. Recent clinical practice recommendations emphasize personalized treatment approaches through addressing treatable traits of chronic cough. Investigations are ongoing to better distinguish chronic cough subgroups, and multiple types of important clinical outcome measures are being characterized. Newer research about chronic cough treatment encompasses pharmacologic and nonpharmacologic interventions, including oral and inhaled medications, superior laryngeal nerve blocks, and behavioral therapy.

SUMMARY

As knowledge about chronic cough in adults continues to expand in both research and clinical practice, otolaryngologists can continue to raise awareness of the role of the larynx in cough and promote ongoing multidisciplinary collaborations. In the coming years, more pharmacologic options and personalized treatment approaches will likely emerge for chronic cough.

Chronic cough as a disease

Chronic cough is a frequent reason for medical consultation and has significant impact on quality of life. Due to the limited effectiveness of currently available treatments, and delays in accessing care, patients are often inadequately managed. There remains an overreliance by clinicians on outdated management algorithms, addressing chronic cough only as symptom of other medical conditions, and advocating investigation and trials of treatment of diseases which are often not present. This may lead to unnecessary cost, frustration and potential harm. Newer clinical guidelines in essence consider chronic cough as a disease in itself, resulting from afferent neuronal hypersensitivity and central nervous system dysfunction. Secondary factors which aggravate chronic cough (smoking, asthma, gastro-oesophageal reflux, etc.) are better considered as treatable traits associated with the primary disease process rather than direct "causes" of cough. Explicitly approaching chronic cough as a discrete entity is consistent with the way in which "diseases" are generally characterised, and has advantages. The patient should be better able to understand their condition, and may have better confidence in attempts at management. The clinician should have better focus and avoid unfruitful treatments and investigation. In general, considering chronic cough as a disease should help to raise the profile of the condition, improve organisation of health service pathways, increase attention for research, and further the development of new treatments.

Exploring the concept of disease control in chronic cough

Background

Disease control in chronic diseases is an overarching concept that reflects the degree to which the goals of therapy are met. However, to date, there is no consensus on the definition of disease control in chronic cough. This study aimed to provide a conceptual exploration of patient-reported cough control in chronic cough.

Methods

This research is comprised of two subanalyses. First, patients with chronic cough receiving care at referral clinics were evaluated. Correlation analyses were performed between patient-reported cough control (a 5-point Likert scale), cough-specific patient-reported outcomes (PROs) and generic health PRO scores. Second, a survey was conducted among patients with refractory chronic cough and physicians to identify factors pertinent to cough control.

Results

The analysis of 341 patients (mean age: 55.5±15.1 years; female: 66.6%) revealed that cough control rating was moderately correlated with cough severity visual analogue scale and Leicester Cough Questionnaire scores, while demonstrating weaker correlations with cough-associated throat symptoms, cough-related complications or general health-related quality of life (QoL). In the survey of patients and physicians, both groups considered certain factors, such as cough frequency, severity and impact on QoL, to be relevant to the concept of cough control. However, patients rated "need for cough rescue drug" notably higher than physicians.

Conclusion

Patient-reported cough control was associated with cough severity or impact on QoL; however, cough control may not be fully captured by conventional cough PRO measurement tools. Further studies are warranted to define the consensus and tools to measure disease control in chronic cough.

Patient's experiences of coughing after lung cancer surgery: A multicenter qualitative study

PURPOSE

Cough is one of the most common symptoms after lung cancer surgery, which seriously affects the quality of life. Little research has been conducted on patient's experiences of cough following lung surgery. This study aimed to elucidate the experience of coughing after lung cancer surgery from the patient's perspective regarding symptoms and their impacts on daily life, as well as triggers and dealing strategies.

METHODS

Between June 2023 and July 2023, we conducted semi-structured interviews with patients from outpatient clinics of two hospitals who were pathologically diagnosed with lung cancer and experienced cough after surgery through convenience sampling. The interview recordings were transcribed and analyzed by two researchers. The traditional content analysis and thematic analysis were used to identify the common codes, subthemes, and themes.

RESULTS

A total of 28 participants were interviewed. The mean age of the participants was 55.21 years (range: 36-75 years), and 21 participants were female. Most patients (75%) were interviewed within 6 months of surgery. We identified five themes (accompanying symptoms, incentives, effects, solution, and information sources) and 12 subthemes (local symptoms, systemic symptoms, personal factors, external factors, emotion, relationship with others, reduced quality of life, medical measures, nonmedical measures, no measures, relatives and friends, and the Internet). Patients with lung cancer may experience various cough symptoms after surgery, which a variety of internal and external factors can trigger. The coughing imposes a double burden on the physical and psychological due to the negative emotions it provokes.

CONCLUSION

We generated a concept framework of cough after lung cancer surgery, providing a basis for further development of measurement tools from the patients' perspective. The lack of knowledge related to coughing highlights the need for adequate and timely health education and professional medical care.

Patient's experiences of coughing after lung cancer surgery: A multicenter qualitative study

Purpose

Cough is one of the most common symptoms after lung cancer surgery, which seriously affects the quality of life. Little research has been conducted on patient's experiences of cough following lung surgery. This study aimed to elucidate the experience of coughing after lung cancer surgery from the patient's perspective regarding symptoms and their impacts on daily life, as well as triggers and dealing strategies.

Methods

Between June 2023 and July 2023, we conducted semi‐structured interviews with patients from outpatient clinics of two hospitals who were pathologically diagnosed with lung cancer and experienced cough after surgery through convenience sampling. The interview recordings were transcribed and analyzed by two researchers. The traditional content analysis and thematic analysis were used to identify the common codes, subthemes, and themes.

Results

A total of 28 participants were interviewed. The mean age of the participants was 55.21 years (range: 36–75 years), and 21 participants were female. Most patients (75%) were interviewed within 6 months of surgery. We identified five themes (accompanying symptoms, incentives, effects, solution, and information sources) and 12 subthemes (local symptoms, systemic symptoms, personal factors, external factors, emotion, relationship with others, reduced quality of life, medical measures, nonmedical measures, no measures, relatives and friends, and the Internet). Patients with lung cancer may experience various cough symptoms after surgery, which a variety of internal and external factors can trigger. The coughing imposes a double burden on the physical and psychological due to the negative emotions it provokes.

Conclusion

We generated a concept framework of cough after lung cancer surgery, providing a basis for further development of measurement tools from the patients' perspective. The lack of knowledge related to coughing highlights the need for adequate and timely health education and professional medical care.

Consensus goals and standards for specialist cough clinics: the NEUROCOUGH international Delphi study

Background

Current guidelines on the management of chronic cough do not provide recommendations for the operation of specialist cough clinics. The objective of the present study was to develop expert consensus on goals and standard procedures for specialist cough clinics.

Methods

We undertook a modified Delphi process, whereby initial statements proposed by experts were categorised and presented back to panellists over two ranking rounds using an 11-point Likert scale to identify consensus.

Results

An international panel of 57 experts from 19 countries participated, with consensus reached on 15 out of 16 statements, covering the aims, roles and standard procedures of specialist cough clinics. Panellists agreed that specialist cough clinics offer optimal care for patients with chronic cough. They also agreed that history taking should enquire as to cough triggers, cough severity rating scales should be routinely used, and a minimum of chest radiography, spirometry and measurements of type 2 inflammatory markers should be undertaken in newly referred patients. The importance of specialist cough clinics in promoting clinical research and cough specialty training was acknowledged. Variability in healthcare resources and clinical needs between geographical regions was noted.

Conclusions

The Delphi exercise provides a platform and guidance for both established cough clinics and those in planning stages.

Baseline Cohort Profile of the Korean Chronic Cough Registry: A Multicenter, Prospective, Observational Study

PURPOSE

The Korean Chronic Cough Registry study was initiated to characterize patients with chronic cough (CC) and investigate their outcomes in real-world clinical practice. This report aims to describe the baseline cohort profile and study protocols.

METHODS

This multicenter, prospective observational cohort study included newly referred CC patients and those already being treated for refractory or unexplained chronic cough (RUCC). Cough status was assessed using a visual analog scale, the Leicester Cough Questionnaire (LCQ), and the Cough Hypersensitivity Questionnaire (CHQ).

RESULTS

A total of 610 patients (66.9% women; median age 59.0 years) were recruited from 18 centers, with 176 being RUCC patients (28.9%). The median age at CC onset was 50.1 years, and 94.4% had adult-onset CC (≥ 19 years). The median cough duration was 4 years. Compared to newly referred CC patients, RUCC patients had a longer cough duration (6.0 years vs. 3.0 years) but had fewer symptoms and signs suggesting asthma, rhinosinusitis, or gastroesophageal acid reflux disease. Subjects with RUCC had lower LCQ scores (10.3 ± 3.3 vs. 11.6 ± 3.6; P < 0.001) and higher CHQ scores (9.1 ± 3.9 vs. 8.4 ± 4.1; P = 0.024). There were no marked differences in the characteristics of cough between refractory chronic cough and unexplained chronic cough.

CONCLUSIONS

Chronic cough typically develops in adulthood, lasting for years. Cough severity and quality of life impairment indicate the presence of unmet clinical needs and insufficient cough control in real-world clinical practice. Longitudinal follow-up is warranted to investigate the natural history and treatment outcomes.