Prevalence and incidence of, and risk factors for chronic cough in the adult population: the Rotterdam Study

Pharmacists' clinical decision making when responding to a self-medication request for a cough in a developing country

BACKGROUND

Some studies have reported that community pharmacies in developing countries, including Indonesia, provided sub-optimal advice when handling patient's self-medication request for cough. The reasons behind such advice, therefore, need to be investigated.

OBJECTIVES

To describe Indonesian pharmacists' clinical decision making when handling self-medication cases for a cough.

METHODS

An open-ended questionnaire consisting of two cough clinical vignettes (case 1: cough due to asthma worsening and case 2: cough as a symptom of common cold) were developed. Pharmacists were interviewed to provide recommendations and reasons for their recommendations for these scenarios. Content analysis was used to analyse participants' statements for the two scenarios. The number of participants who provided appropriate recommendations and reasons were then counted.

RESULTS

A total of 245 community pharmacists participated in the study. In the case of cough due to asthma worsening, recommending a product because the product was indicated to help with the symptoms was the most common recommendation and stated reason (40%). Appropriate recommendation (direct medical referral) with appropriate reasoning (indicating warning symptoms and/or making a symptom diagnosis) was provided by 25% participants. In the case of cough as a symptom of common cold, recommending products to help with the symptoms was also the most common recommendation and stated reason (53%). Appropriate recommendations (recommending product) with appropriate reasoning (providing product to treat the symptoms and/or indicating no warning symptoms and/or making a symptom diagnosis) was provided by 81% participants.

CONCLUSION

The ability of Indonesian community pharmacists to provide appropriate recommendations for cough self-medication requests is dependent on whether triage is required. The inability of most community pharmacists to differentiate between major and minor conditions may lead to serious health implications for patients and therefore educational interventions should be undertaken to improve community pharmacists' differential diagnostic skills for triage.

A systematic review of the psychometric properties of the Leicester Cough Questionnaires based on the COSMIN guidelines

BACKGROUND

Chronic cough affects around 10 % of the general adult population, impairing all aspects of quality of life.

RESEARCH QUESTION

What are the Leicester Cough Questionnaire's psychometric properties?

STUDY DESIGN AND METHODS

Electronic searches of PubMed, CINAHL, and ScienceDirect databases were conducted from inception until October 1rst 2022. All full-text articles, published in French or English, aimed at evaluating the LCQ's content validity or psychometric properties were included. The COSMIN Risk of Bias checklist was applied to assess their methodological quality and results. Results were qualitatively summarised and rated by a modified GRADE approach.

RESULTS

40 studies were included accounting for 8731 adults, subject to cough or a respiratory condition. Chronic cough (>8 weeks) was the most represented. The LCQ's total score is relevant and comprehensible for the assessment of the impact of cough on QoL. The original 3-factor model showed a satisfactory model fit. Good convergent validity was found for the total and physical domain scores. These scores demonstrate good internal consistency and test retest reliability, with some variability noted and they are responsive to change. Recent estimates of MID thresholds were 1.7 and 0.4 for total and domain scores respectively. The quality of the studies is globally poor.

INTERPRETATION

The LCQ is a valid outcome to assess the intra-individual impact of cough on QoL and to detect large changes in quality of life mainly in a short-term clinical trial setting.

CLINICAL TRIAL REGISTRATION

The protocol was registered with PROSPERO (CRD42022355191).

Characteristics of US Medicare Beneficiaries with Chronic Cough vs. Non-Chronic Cough: 2011-2018

Background: Chronic cough (CC), characterized as a cough lasting >8 weeks, is a common multi-factorial syndrome in the community, especially in older adults. Methods: Using a pre-existing algorithm to identify patients with CC within the 2011-2018 Medicare beneficiaries, we examined trends in gabapentinoid use through repeated cross-sectional analyses and identified distinct utilization trajectories using group-based trajectory modeling (GBTM) in a retrospective cohort study. Individuals without CC but with any respiratory conditions related to cough served as a comparator group. Results: Among patients with CC, gabapentinoid use increased from 18.6% in 2011 to 24.1% in 2018 (p = 0.002), with a similar upward trend observed in the non-CC cohort but with overall lower usage (14.7% to 18.4%; p < 0.001). Patients with CC had significantly higher burdens of respiratory and non-respiratory comorbidities, as well as greater healthcare service and medication use compared to the non-CC cohort. The GBTM analyses identified three distinct gabapentinoid utilization trajectories for CC and non-CC patients: no use (77.3% vs. 84.5%), low use (13.9% vs. 10.3%), and high use (8.8% vs. 5.2%). Conclusions: Future studies are needed to evaluate the safety and effectiveness of gabapentinoid use in patients with refractory or unexplained CC in real-world settings.

Burden of Disease Associated with Refractory and Unexplained Chronic Cough in Canada: Results from a National Survey

INTRODUCTION

Chronic cough (persisting for ≥ 8 weeks) is a common disorder that includes refractory chronic cough (RCC; cough that persists despite treatment of underlying disease) and unexplained chronic cough (UCC; cough with no identifiable cause). We evaluated self-reported health-related quality of life (HR-QoL) and work/activity impairment associated with RCC/UCC in Canada.

METHODS

Our exploratory study included Canadians in the Leger Opinion Panel with RCC or UCC. Key entry criteria were ≥ 18 years of age, cough for ≥ 8 weeks, not currently smoking/quit ≥ 1 year ago, no serious respiratory disease or lung cancer, and not taking angiotensin-converting enzyme inhibitors. Respondents completed a 30-min online survey with general and cough-specific HR-QoL questionnaires, including the EuroQol (EQ) visual analogue scale (VAS), EQ-5-dimension 5-level (EQ-5D-5L), cough severity VAS, Leicester Cough Questionnaire (LCQ), and Work Productivity and Activity Impairment-Specific Health Problem (WPAI-SPH).

RESULTS

Of 49,076 individuals who completed the chronic cough screening questionnaire (July 30-September 1, 2021), 1,620 (3.3%) met entry criteria for RCC/UCC and 1,046 (2.1%) completed the survey. The mean age of respondents was 45 years and 61% were female. Respondents reported impairments in global HR-QoL (EQ-VAS 73.8, 61% with anxiety/depression on the EQ-5D-5L) and cough-specific HR-QoL (mean cough severity VAS score 29.7, LCQ index 15.2). Work and non-work activities were reduced by 34% and 30%, respectively, on the WPAI-SPH.

CONCLUSION

RCC/UCC is prevalent in Canada and associated with impaired HR-QoL, particularly in mental health domains. Additional support and management options may be required to fully address this burden.

Uncontrolled mild-to-moderate asthma may not be mild or moderate, or even asthma: The benefits of early phenotyping

See related article

Cerebellar ataxia, neuropathy and vestibular areflexia syndrome: a neurogenic cough prototype

Chronic cough is a frequent disorder that is defined by cough of more than 8 weeks duration. Despite extensive investigation, some patients exhibit no aetiology and others do not respond to specific treatments directed against apparent causes of cough. Such patients are identified as having unexplained or refractory chronic cough. Recently, a high proportion of patients with chronic cough in the context of cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) was highlighted. CANVAS is a rare neurological disorder with a biallelic variation in the replication factor C subunit 1 (RFC1) gene corresponding mostly to an intronic AAGGG repeat expansion. Chronic cough in patients with CANVAS shares similar characteristics with cough hypersensitivity syndrome. The high prevalence of chronic cough in CANVAS gives the opportunity to better understand the neurogenic mechanism of chronic cough. In this review, we will describe the characteristics and mechanisms of CANVAS. We will also address the potential mechanisms responsible for chronic cough in CANVAS. Finally, we will address chronic cough management in the context of CANVAS.

Prevalence, clinical characteristics, and disease burden of chronic cough in Italy: a cross-sectional study

BACKGROUND

Chronic cough has been associated with reduced health-related quality of life, negative impacts on sleep, work, and other daily activities, and increased use of health care resources. Little is known about the prevalence of chronic cough in Italy. In the present study we sought to estimate the prevalence of chronic cough in Italy, describe sociodemographic and clinical characteristics associated with chronic cough, and characterize the impact of chronic cough on overall health and wellness, work and other daily activities, and health care resource use.

METHODS

We conducted a cross-sectional study to collect sociodemographic and health-related data from Italian residents who participated in the 2020 National Health and Wellness Survey (N = 10,026). To assess the characteristics and burden of chronic cough, adults who indicated that they had experienced chronic cough during the prior 12 months were compared with propensity score-matched controls without chronic cough.

RESULTS

The estimated weighted lifetime and 12-month prevalence of chronic cough were estimated as 9.2% and 6.3%, respectively. Compared with matched controls, respondents with chronic cough had significantly lower measures of overall physical and mental health (P < .001 for both comparisons), and significantly higher rates of anxiety, depression, and sleep disorders (P < .001 for all comparisons). Chronic cough was significantly associated with higher rates of impairment of work and other activities (P < .001 for all comparisons) in the past 7 days, any-cause emergency department visits and hospitalizations in the prior 6 months (P < .001 for both comparisons), and more visits to general and specialist health care providers (P < .001 for both comparisons) in the prior 6 months.

CONCLUSIONS

In Italy, chronic cough affects an estimated 3.3 million adults annually and represents a significant burden to individuals and the health care system.

TAKE HOME MESSAGE

Little is known about the prevalence of chronic cough in Italy. We found that, in Italy chronic cough represents a significant burden to individuals and the health care system, affecting an estimated 3.3 million adults annually.

Chronic Cough and Obstructive Sleep Apnea

Chronic cough, defined as a cough lasting more than 8 weeks, is a common medical condition occurring in 5% to 10% of the population. Its overlap with another highly prevalent disorder, obstructive sleep apnea (OSA), is therefore not surprising. The relationship between chronic cough and OSA extends beyond this overlap with higher prevalence of OSA in patients with chronic cough than in the general population. The use of continuous positive airway pressure can result in improvement in chronic cough although further studies are needed to understand which patients will experience benefit in their cough from the treatment of comorbid OSA.

Epidemiology and Healthcare Service Utilization among Adults with Chronic Cough

Background and objective: Chronic cough (CC) is a prevalent yet underexplored medical condition, with limited real-world data regarding its healthcare burden. This study investigates the epidemiology, associated comorbidities, and healthcare service utilization among patients with CC. Methods: In this retrospective cohort study, adult patients with at least 3 physician diagnoses of cough over a period spanning a minimum of 8 weeks and a maximum of 12 months anytime between 2009 and 2018, were defined as patients with CC (PwCC). The reference group were adults without cough matched in a 1:1 ratio for age, sex, and place of residence. Results: The study included 91,757 PwCC, reflecting a prevalence of 5.5%. Of those, 59,296 patients (mean [SD] age, 53.9 [16.8] years; 59.6% females) were first diagnosed with CC during the study period, representing a 10-year incidence rate of 3.26% (95%CI: 3.24-3.29%). Diseases associated with the highest OR for CC included lung cancer (OR = 3.32; 95%CI: 2.90-4.25), whooping cough (OR = 3.04; 95%CI: 2.70-3.60), and respiratory infections (OR = 2.81; 95%CI: 2.74-2.88). Furthermore, PwCC demonstrated increased healthcare service utilization, leading to a higher adjusted annual estimated mean cost (USD 4038 vs. USD 1833, p < 0.001). Conclusions: Chronic cough emerges as a relatively prevalent complaint within community care, exerting a considerable economic burden. This study underscores the need for heightened awareness, comprehensive management strategies, and resource allocation to address the multifaceted challenges associated with chronic cough.

Prevalence and burden of chronic cough in France

Background

Chronic cough is a common condition that is associated with lower health-related quality of life and greater healthcare resource use. There are limited data on the prevalence, population characteristics and burden of chronic cough in France.

Methods

This was a cross-sectional study based on responses from French adult residents to the 2020 National Health and Wellness Survey. Respondents with chronic cough were compared to 1:3 propensity score-matched controls without chronic cough.

Results

The weighted lifetime and 12-month prevalence of chronic cough were estimated as 7.5% and 4.8%, respectively. Respondents with chronic cough reported significantly worse perceived health than matched controls, with lower mean±sd scores of 46.68±9.28 versus 50.42±8.26 on the physical health component and 40.32±9.87 versus 44.32± 9.69 on the mental health component of the Medical Outcomes Study 12-item Short Form Survey Version 2 survey (p<0.001 for both comparisons). Respondents with chronic cough also had higher rates of moderate-to-severe forms of anxiety (24.4% versus 12.4%) and depression (36.4% versus 20.2%); higher rates of multiple forms of sleep disturbance; greater impairment of work productivity (38.2% versus 25.5%) and other activities (41.8% versus 28.2%; p<0.001 for all comparisons). Respondents with chronic cough also had higher rates of all-cause healthcare resource use including emergency room visits, hospitalisation, and overall and specialist healthcare provider visits compared to controls (p<0.001 for all comparisons).

Conclusion

Chronic cough is a common condition in France that is associated with lower health-related quality of life and greater healthcare resource utilisation.

The Rotterdam Study. Design update and major findings between 2020 and 2024

The Rotterdam Study is a population-based cohort study, started in 1990 in the district of Ommoord in the city of Rotterdam, the Netherlands, with the aim to describe the prevalence and incidence, unravel the etiology, and identify targets for prediction, prevention or intervention of multifactorial diseases in mid-life and elderly. The study currently includes 17,931 participants (overall response rate 65%), aged 40 years and over, who are examined in-person every 3 to 5 years in a dedicated research facility, and who are followed-up continuously through automated linkage with health care providers, both regionally and nationally. Research within the Rotterdam Study is carried out along two axes. First, research lines are oriented around diseases and clinical conditions, which are reflective of medical specializations. Second, cross-cutting research lines transverse these clinical demarcations allowing for inter- and multidisciplinary research. These research lines generally reflect subdomains within epidemiology. This paper describes recent methodological updates and main findings from each of these research lines. Also, future perspective for coming years highlighted.

Prevalence of chronic cough, its risk factors and population attributable risk in the Burden of Obstructive Lung Disease (BOLD) study: a multinational cross-sectional study

Background

Chronic cough is a common respiratory symptom with an impact on daily activities and quality of life. Global prevalence data are scarce and derive mainly from European and Asian countries and studies with outcomes other than chronic cough. In this study, we aimed to estimate the prevalence of chronic cough across a large number of study sites as well as to identify its main risk factors using a standardised protocol and definition.

Methods

We analysed cross-sectional data from 33,983 adults (≥40 years), recruited between Jan 2, 2003 and Dec 26, 2016, in 41 sites (34 countries) from the Burden of Obstructive Lung Disease (BOLD) study. We estimated the prevalence of chronic cough for each site accounting for sampling design. To identify risk factors, we conducted multivariable logistic regression analysis within each site and then pooled estimates using random-effects meta-analysis. We also calculated the population attributable risk (PAR) associated with each of the identifed risk factors.

Findings

The prevalence of chronic cough varied from 3% in India (rural Pune) to 24% in the United States of America (Lexington,KY). Chronic cough was more common among females, both current and passive smokers, those working in a dusty job, those with a history of tuberculosis, those who were obese, those with a low level of education and those with hypertension or airflow limitation. The most influential risk factors were current smoking and working in a dusty job.

Interpretation

Our findings suggested that the prevalence of chronic cough varies widely across sites in different world regions. Cigarette smoking and exposure to dust in the workplace are its major risk factors.

Funding

Wellcome Trust.

Evaluation and management of chronic cough in adults

Background: Chronic cough (CC), a cough that lasts > 8 weeks, has an overall prevalence of 5-11% in adults, peaking between 60 and 80 years of age. Of the 15% of patients who remain undiagnosed or refractory to treatment, two thirds are women. Objective: The objective was to present an updated evidence-based algorithmic approach for evaluating and managing CC, with emphasis on treatment modalities for refractory CC. Methods: A literature search was conducted of medical literature data bases for guidelines, position papers, systematic reviews, and clinical trials from January 2022 to June 2023, on the evaluation and management of CC. Results: The initial assessment should be limited to a detailed history, physical examination, chest radiograph, spirometry, exhaled nitric oxide, blood eosinophil count, and measurement of cough severity and quality of life by using validated instruments. The top diagnoses to consider are asthma, chronic obstructive pulmonary disease, nonasthmatic eosinophilic bronchitis, gastroesophageal reflux disease, and upper airway cough syndrome. Additional studies are only obtained when red flags are present or the patient fails to respond after avoidance of high-risk factors, e.g., smoking and angiotensin-converting enzyme inhibitors, and 4-6 weeks of empiric treatment for the most likely respiratory and gastrointestinal diseases. When diagnostic tests and/or specific directed treatments fail to control CC, low-dose morphine (preferred), gabapentin, pregabalin, and/or cough control therapy are recommended. Non-narcotic purinergic 2×3 (P2×3) receptor antagonists, gafapixant and campilixant, are currently being studied for CC. Conclusion: For the evaluation and management of patients with CC, clinicians should use an algorithmic approach and identify "red flags," reduce high-risk factors, and use empiric treatment for the five top diagnoses before extensive diagnostic testing. Current treatment for refractory cough is limited to symptomatic management.

Disease burden, comorbidities and antecedents of chronic cough phenotypes in Australian adults

BACKGROUND AND OBJECTIVES

While adult chronic cough has high burden, its phenotypes, particularly those without aetiologically related underlying conditions, are understudied. We investigated the prevalence, lung function and comorbidities of adult chronic cough phenotypes.

METHODS

Data from 3608 participants aged 53 years from the Tasmanian Longitudinal Health Study (TAHS) were included. Chronic cough was defined as cough on most days for >3 months in a year. Chronic cough was classified into "explained cough" if there were any one of four major cough-associated conditions (asthma, COPD, gastroesophageal reflux disease or rhinosinusitis) or "unexplained cough" if none were present. Adjusted regression analyses investigated associations between these chronic cough phenotypes, lung function and non-respiratory comorbidities at 53 years.

RESULTS

The prevalence of chronic cough was 10% (95%CI 9.1,11.0%) with 46.4% being "unexplained". Participants with unexplained chronic cough had lower FEV1/FVC (coefficient: -1.2% [95%CI:-2,3, -0.1]) and increased odds of comorbidities including obesity (OR=1.6 [95%CI: 1.2, 2.3]), depression (OR=1.4 [95%CI: 1.0, 2.1]), hypertension (OR=1.7 [95%CI: 1.2, 2.4]) and angina, heart attack or myocardial infarction to a lesser extent, compared to those without chronic cough. Participants with explained chronic cough also had lower lung function than both those with unexplained chronic cough and those without chronic cough.

CONCLUSIONS

Chronic cough is prevalent in middle-age and a high proportion is unexplained. Unexplained cough contributes to poor lung function and increased comorbidities. Given unexplained chronic cough is not a symptom of major underlying respiratory conditions it should be targeted for better understanding in both clinical settings and research.

Medical Diagnosis Reimagined as a Process of Bayesian Reasoning and Elimination

This article delves into the interface between the art of medical diagnosis and the mathematical foundations of probability, the Bayes theorem. In a healthcare ecosystem witnessing an artificial intelligence (AI)-driven transformation, understanding the convergence becomes crucial for physicians. Contrary to viewing AI as a mysterious "black box," we demonstrate how every diagnostic decision by a medical practitioner is, in essence, Bayesian reasoning in action. The Bayes theorem is a mathematical translation of systematically updating our belief: it quantifies how an additional piece of information updates our prior belief in something. Using a clinical scenario of Kartagener syndrome, we showcase the parallels between a physician's evolving diagnostic thought process and the mathematical updating of prior beliefs with new evidence. By reimagining medical diagnosis through the lens of Bayes, this paper aims to demystify AI, accentuating its potential role as an enhancer of clinical acumen rather than a replacement. The ultimate vision presented is one of harmony, where AI serves as a symbiotic partner to physicians, with the shared goal of holistic patient care.

The P2X3 receptor antagonist filapixant in patients with refractory chronic cough: a randomized controlled trial

BACKGROUND

P2X3 receptor antagonists seem to have a promising potential for treating patients with refractory chronic cough. In this double-blind, randomized, placebo-controlled study, we investigated the efficacy, safety, and tolerability of the novel selective P2X3 receptor antagonist filapixant (BAY1902607) in patients with refractory chronic cough.

METHODS

Following a crossover design, 23 patients with refractory chronic cough (age: 60.4 ± 9.1 years) received ascending doses of filapixant in one period (20, 80, 150, and 250 mg, twice daily, 4-days-on/3-days-off) and placebo in the other. The primary efficacy endpoint was the 24-h cough frequency on Day 4 of each dosing step. Further, subjective cough severity and health-related quality of life were assessed.

RESULTS

Filapixant at doses ≥ 80 mg significantly reduced cough frequency and severity and improved cough health-related quality of life. Reductions in 24-h cough frequency over placebo ranged from 17% (80 mg dose) to 37% (250 mg dose), reductions over baseline from 23% (80 mg) to 41% (250 mg) (placebo: 6%). Reductions in cough severity ratings on a 100-mm visual analog scale ranged from 8 mm (80 mg) to 21 mm (250 mg). No serious or severe adverse events or adverse events leading to discontinuation of treatment were reported. Taste-related adverse events occurred in 4%, 13%, 43%, and 57% of patients treated with filapixant 20, 80, 150, and 250 mg, respectively, and in 12% treated with placebo.

CONCLUSIONS

Filapixant proved to be efficacious, safe, and-apart from the occurrence of taste disturbances, especially at higher dosages-well tolerated during the short therapeutic intervention. Clinical trial registration EudraCT, eudract.ema.europa.eu, 2018-000129-29; ClinicalTrials.gov, NCT03535168.

Can clinical characteristics differentiate patients with unexplained chronic cough from patients with asthma and COPD?

Background: Chronic cough is reported in up to 20% of the adult population and often persists despite medical treatment with currently available therapies. Many clinical conditions, including asthma and chronic obstructive pulmonary disease (COPD), must be excluded before making a Unexplained chronic cough diagnosis. Methods: The primary objective was to use a large hospital dataset to compare clinical features of patients with a primary diagnosis of UCC with those with asthma or COPD without a primary diagnosis of UCC to help clinicians differentiate between these conditions more readily. Data were collected for all hospitalization and outpatient medical encounters for each patient between November 2013 and December 2018. Information included demographics, encounter dates, medications prescribed at every encounter for chronic cough, lung function testing, and hematologic parameters. Asthma and COPD were combined into one group to ensure there was no overlap with UCC and due to limitations of International Classification of Diseases coding to confirm an asthma(A)/COPD diagnosis. Results: Female gender represented 70% of encounters for UCC versus 61.8% for asthma/COPD (p < 0.0001); the mean age was 56.9 years for UCC versus 50.1 years for A/COPD (p < 0.0001). The number of patients on cough medications and the cough medication frequency were significantly higher in the UCC versus A/COPD group (p < 0.0001). UCC versus A/COPD patients had a total of eight versus three cough-related encounters over the study duration (i.e., 5 years) (<0.0001). The average interval between successive encounters was less for UCC (114 days) versus the A/COPD (288 days) group. Gender-adjusted Forced expiratory volume in the first second of exhalation/Forced vital capacity (FEV₁/FVC) ratios, residual volume%, and Diffusion capacity for carbon monoxide (DLCO%) were significantly higher in UCC versus A/COPD, whereas the response to bronchodilators of FEV₁, FVC and residual volumes were significantly greater in A/COPD patients. Conclusions: Clinical characteristics differentiating UCC from A/COPD could accelerate recognition of UCC diagnosis especially in the subspecialty setting where patients with these disorders are referred.

Lung Health in Farming: A Scoping Review

OBJECTIVE

Lung disease is now recognized as an associated occupational hazard among farming and agricultural communities, however limited research surrounds lung health knowledge within our farming population. It is clear from this limited lack of knowledge that farming practices, perceptions and ideas relating to lung health are yet to be uncovered. This scoping review was conducted to identify what is known about lung health within farming and agricultural communities globally and to map the available evidence relating to lung health and lung health decline within this population. The objectives of this review were (1) focus on available lung health research from a global perspective specific to farming and agriculture relating to occupational lung exposures and (2) consolidate current knowledge, clearly identifying gaps within the literature.

METHODS

This systematic scoping review of the literature is guided by the Joanna Briggs Institute Methodology framework. There were 22 studies eligible for inclusion within the scoping review, providing an up-to-date review of research conducted on lung health and lung disease in farming occupations.

RESULTS

Results were grouped into three categories emerging from included studies: (1) focused on the prevalence of respiratory symptoms/disease within farming and agricultural occupations, (2) measurements of dust and particulate matter and correlating these with respiratory conditions, (3) common respiratory conditions linked to a decline in lung health among farming and agricultural occupations. Results identified no study focused on or referred to lung health, lung health knowledge or lung health awareness as an outcome, with all studies focusing on respiratory symptoms, development of lung disease and the common occupational hazards this population are exposed to.

CONCLUSION

This scoping review demonstrates the lack of literature to specifically map available evidence relating to lung health and farming occupations. Many respiratory symptoms and conditions can arise directly and indirectly from agricultural environments, however many of these cases could be prevented by lung health knowledge within the farming population. The results of this scoping review will be used to inform knowledge, awareness, education, health promotion and future research within this population.

Chronic Cough-Related Differences in Brain Morphometry in Adults: A Population-Based Study

BACKGROUND

Individuals with cough hypersensitivity have increased central neural responses to tussive stimuli, which may result in maladaptive morphometric changes in the central cough processing systems.

RESEARCH QUESTION

Are the volumes of the brain regions implicated in cough hypersensitivity different in adults with chronic cough compared with adults without chronic cough?

STUDY DESIGN AND METHODS

Between 2009 and 2014, participants in the Rotterdam Study, a population-based cohort, underwent brain MRI and were interviewed for chronic cough, which was defined as daily coughing for at least 3 months. Regional brain volumes were quantified with the use of parcellation software. Based on literature review, we identified and studied seven brain regions that previously had been associated with altered functional brain activity in chronic cough. The relationship between chronic cough and regional brain volumes was investigated with the use of multivariable regression models.

RESULTS

Chronic cough was prevalent in 9.6% (No. = 349) of the 3,620 study participants (mean age, 68.5 ± 9.0 years; 54.6% women). Participants with chronic cough had significantly smaller anterior cingulate cortex volume than participants without chronic cough (mean difference, -126.16 mm³; 95% CI, -245.67 to -6.66; P = .039). Except for anterior cingulate cortex, there were no significant difference in the volume of other brain regions based on chronic cough status. The volume difference in the anterior cingulate cortex was more pronounced in the left hemisphere (mean difference, -88.11 mm³; 95% CI, -165.16 to -11.06; P = .025) and in men (mean difference, -242.58 mm³; 95% CI, -428.60 to -56.55; P = .011).

INTERPRETATION

Individuals with chronic cough have a smaller volume of the anterior cingulate cortex, which is a brain region involved in cough suppression.

CLINICAL TRIAL REGISTRATION

The Netherlands National Trial Registry (NTR; www.trialregister.nl) and the World Health Organization's International Clinical Trials Registry Platform (ICTRP; www.who.int/ictrp/network/primary/en/) under the joint catalogue number NTR6831.

The demographics, clinical characteristics and quality of life of patients with chronic cough from the Isala Cough Clinic in the Netherlands

Introduction

Chronic cough affects ∼10% of the population and adversely impacts quality of life. This retrospective observational cohort study aimed to identify the demographics, clinical characteristics and quality of life of the chronic cough population in a Dutch chronic cough clinic, at baseline and following treatment at 6 months. Patients were categorised based on the underlying phenotype and response to treatment.

Methods

Retrospective data on 2397 patients who were diagnosed according to standard guidelines of the American College of Chest Physicians were analysed. Quality of life was captured via the Leicester Cough Questionnaire, the Cough Numeric Rating Scale and the Hospital Anxiety and Depression Scale.

Results

Mean patient age was 59 years; 62.5% of the patients were female; and 69.1% had at least one underlying phenotype associated with chronic cough. Of the latter, 52.1% had bronchial hyperresponsiveness/airflow limitation, 33.3% had airway reflux and 20.1% had upper airway cough syndrome. 46% of patients with a phenotype, and 51% without, experienced no improvement in their quality of life or still had significant cough remaining after 6 months. Of patients with available quality-of-life data, 37.5% were categorised as having refractory chronic cough, and 9.5% were categorised as unexplained chronic cough.

Discussion

This study highlights the poor quality-of-life outcomes in patients with chronic cough, despite interventions to treat underlying conditions, and indicates a need to manage chronic cough irrespective of phenotype.

Narrative Review of the Mechanisms and Treatment of Cough in Asthma, Cough Variant Asthma, and Non-asthmatic Eosinophilic Bronchitis

Chronic cough is a debilitating condition affecting 10-12% of the general population and is one of the leading causes for referral to secondary care. Many conditions have been associated with chronic cough, including asthma, gastro-esophageal reflux disease and upper airways cough syndrome. Inflammatory airway conditions including cough variant asthma (CVA) and non-asthmatic eosinophilic bronchitis (NAEB) contribute to a significant proportion of presentations with chronic cough, with differing diagnostic criteria and different responses to commonly used asthma therapy for their respective diagnoses. Mechanistic studies in both animal models and humans have identified increased neuronal sensitivity and subsequent central sensitization. These mechanisms include inflammatory-mediated nociceptor sensitization and alterations of afferent nerve terminal excitability, phenotypic changes in the vagal afferent neurons over time, and central neuroplasticity resulting from increased synaptic signalling from peripheral afferents. The aim of this review is to discuss the mechanisms, neurophysiology, and management approaches currently available for patients presenting with chronic cough with underlying asthma, CVA, and NAEB and to shed a light on areas of further research required to elucidate the mechanisms of cough in this patient population.

Clinical characteristics and drug utilisation patterns in patients with chronic cough: a retrospective cohort study using a Japanese claims database

BACKGROUND

Although unmet medical needs for better care of patients with chronic cough exist in Japan, epidemiological information about these patients and their treatments is very limited.

OBJECTIVES

To describe patient characteristics, underlying cough-related diseases and drug utilisation patterns in patients with chronic cough, and their changes over time.

METHODS

This large retrospective claims database study enrolled subjects with chronic cough, identified either by a specific diagnostic cough code for chronic cough (Population 1) or by multiple cough-related diagnostic codes spanning > 8 weeks (Population 2). Within Population 2, patients with each of the three most frequent diagnostic cough codes were analysed as subgroups. Patient characteristics, underlying cough-related diseases and utilisation patterns for drugs used for cough were documented at the index date, during the 6-month pre-index period and during the 12-month post-index period.

RESULTS

6,038 subjects were enrolled in the cohort (Population 1: N = 3,500; Population 2: N = 2,538). The mean age was 43.7 ± 12.2 years and 61.8% were women. The largest cough diagnosis subgroups in Population 2 were 'other coughs' (N = 1,444), 'cough-variant asthma' (N = 1,026) and 'atopic/allergic cough' (N = 105). At the index date, the most frequent underlying cough-related diseases were allergic rhinitis/nasal inflammation (N = 3,132; 51.9%), asthma (N = 2,517; 41.7%) and gastro-esophageal reflux disease (N = 829; 13.7%). At the index date, 4,860 participants (80.5%) were prescribed at least one cough-related treatment. 194 participants (4.0% of medication users) were prescribed central antitussives alone, principally in Population 1, and 2,331 (48.0%) were prescribed expectorants. Other frequently prescribed medications were antiallergic drugs (N = 2,588; 53.3%), antimicrobials (N = 1,627; 34.4%) and inhaled corticosteroids with long-acting beta-agonists (N = 1,404; 28.9%). Over time, cough diagnoses tended to be lost, with only 470 participants in Population 1 retaining a diagnostic code for chronic cough one year later. The frequency of underlying cough-related diseases was stable over time.

CONCLUSIONS

Patients in this cohort with chronic cough are most frequently identified by a diagnostic cough code for chronic cough, followed by codes for other coughs, cough-variant asthma and atopic cough. Chronic cough frequently presents with an underlying cough-related disease, most frequently allergic rhinitis/nasal inflammation, asthma or GERD. Medication prescription for the underlying cough-related diseases was generally appropriate.

Impact of high-risk of obstructive sleep apnea on chronic cough: data from the Korea National Health and Nutrition Examination Survey

Background

Chronic cough is an extremely common clinical symptom of various diseases. However, the relationship between obstructive sleep apnea (OSA) and chronic cough in the general population has not been sufficiently studied.

Methods

Using the 2019 Korean National Health and Nutrition Examination Survey data, we identified a group at high-risk of OSA via the STOP-Bang questionnaire and determined the association between OSA and chronic cough by a regression model.

Results

Of the eligible 4,217 participants, 97.1% and 2.9% were classified into the non-chronic cough and chronic cough groups, respectively. The chronic cough group had higher STOP-Bang scores than those of the group without chronic cough (2.32 ± 1.38 vs. 2.80 ± 1.39; P < 0.001). In the group at high-risk of OSA, 40.4% and 52.0% of participants scored ≥ 3 in STOP-Bang, depending on the absence or presence of chronic cough (P = 0.012), respectively. Chronic cough independently correlated with impaired lung function (forced expiratory volume in one second ≥ 50–<80% predicted value, P = 0.001; <50, P < 0.001), low household income (P = 0.015), and a group at high-risk of OSA (STOP-Bang score 3–4, P = 0.004; 5–8, P < 0.001). Obesity I had a protective role against the occurrence of chronic cough (P = 0.023).

Conclusion

A high-risk for OSA is a significant risk factor for chronic cough. OSA should be considered when evaluating chronic cough patients.

Management and referral patterns for new-onset chronic cough in primary care patients

Background: The diagnosis and management of chronic cough in primary care is challenging despite it being one of the most common chronic conditions. Objective: Clinical characterization of patients with new-onset chronic cough in the primary care setting. Methods: This was a retrospective study of adult patients (ages ≥ 18 years) with at least three visits with primary care providers (PCP) for new-onset cough, with at least 8 weeks between the first and third visits, within a tertiary-care center and affiliated clinics between January 1, 2010, and January 1, 2019 (N = 174). We calculated the frequency of primary care visits, diagnostic testing, specialist referrals, and prescribed medications up to 18 months after the third visit with a PCP for cough. Results: Of 174 patients who met the criteria of new-onset chronic cough, >50% had four or more primary care visits related to cough. Despite that, 91 (52.3%) did not receive a referral to a specialist, and 41 (23.5%) did not receive an order for a chest radiograph during the evaluation of the chronic cough. Antibiotics and systemic corticosteroids were prescribed to 106 (61%) and 63 (36%) of the patients, respectively, and 20% were prescribed opiates. No patients were prescribed central-neuromodulating agents, and angiotensin-converting enzyme inhibitors were discontinued in 48% of the patients who were taking them (12/25). Conclusion: We found considerable heterogeneity and discrepancies with clinical guideline recommendations in patients who presented with new chronic cough. There is a substantial unmet need to study chronic cough in the primary care setting to inform important stakeholders.

Impact of refractory and unexplained chronic cough on disease burden: a qualitative study

Background

Chronic cough lasting for > 8 weeks is a common medical condition that burdens patients. This study aimed to qualitatively describe knowledge, awareness, experiences, and subtypes of burdens (physical, social, psychological) among Japanese patients with refractory chronic cough (refractory to treatment of underlying relevant medical conditions) and unexplained chronic cough (symptoms of unexplained origin).

Methods

This non-interventional, cross-sectional study was conducted between February and March 2021 among patients (aged ≥ 20 years) with self-reported refractory or unexplained chronic cough. Subjects with a history of comorbid respiratory conditions were excluded. Eligible subjects participated in a 60-min online semi-structured interview. Verbatim terms from interviews were qualitatively transcribed and generated into word clouds, followed by a clustering analysis in which meaningful clusters were chosen, manually coded, and utterances and burdens categorized.

Results

A total of 21 participants (95.2% with refractory chronic cough, mean age 53.5 years, and 76.2% being males) with Leicester Cough Questionnaire mean ± standard deviation scores of physical 4.8 ± 1.1, psychological 4.4 ± 1.3, social 4.9 ± 1.4, and total 14.1 ± 3.5 were included. The word cloud identified the most frequently used word (‘cough’); etiology (‘asthma’); and words associated with change in states (‘influence,’ ‘changing,’ ‘change’) and expressions (‘tough,’ ‘pain,’ ‘hard,’ ‘terrible,’ ‘unpleasant’). The patients experienced ‘mental/social burden,’ ‘physical burden,’ ‘impact on sleep and meals,’ ‘impact on work and housework,’ ‘impact on communication,’ ‘impact on hobbies and leisure,’ and ‘economic burden.’ By closed coding analysis, the situations or types of burden patients experienced from the cough were ordered sequentially as emotion, working style, acquaintanceship, hobbies and leisure, and sleeping pattern.

Conclusions

The present study indicated that there were two types of participant clusters, in which one showed mainly the burdens in the social communications such as work-related communication and another one showed the burdens of relationships with others. Also, some participants highlighted ‘mental burden,’ on social life due to the current pandemic. To relieve these burdens, disease awareness and knowledge should be improved for patients with refractory and unexplained chronic cough.

Trial registration The trial was registered under UMIN-CTR as UMIN000042772, on 17/12/2020. The study was approved by the Medical Corporation Toukeikai Kitamachi Clinic (IRB registration number: 11001110).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02171-z.

Understanding physician's knowledge and perception of chronic cough in Switzerland

BACKGROUND

Cough is one of the most common health issues for which medical attention is sought. A chronic cough (CC) is understood as a cough that lasts longer than 8 weeks. CC encompasses two subsets referred to as refractory chronic cough (RCC) and unexplained chronic cough (UCC). This study aims to assess the current understanding and perceptions of a RCC and UCC, from a physician's perspective in Switzerland and how this understanding and practical work leads to the relevant diagnosis and treatment.

METHODS

In October 2020, 549 GPs and 338 pulmonologists in Switzerland, received an invite to participate in the online-based quantitative survey. Data collection was carried out through a 25-minute online survey. The questionnaire was based on structured questions, and conducted on a randomized sample of doctors (general practitioners -GPs and pulmonologists) in the German- and French-speaking part of Switzerland.

RESULTS

Overall, 33 pulmonologists and 52 GPs participated in the online survey. Only 39% of GPs, but 73% of pulmonologists, defined chronic cough as a cough lasting 8 weeks or longer. The majority of physicians (72%), especially pulmonologists (88%), perceived a clinical gap regarding the treatment of persistent cough. 74% of the sampled physicians agreed that persistent cough is a high burden of disease for patients. Based on the answers, the annual number of new patients with RCC and UCC in Switzerland is estimated at 9322 patients.

CONCLUSIONS

Results of this study have highlighted differences in the terminology used to describe CC (RCC and UCC), in the diagnostic tests used and, in the treatments used between GPs and pulmonologists. These findings suggest the need to align the current language regarding the disease to facilitate a standardized approach for diagnosis and treatment and towards improving patient care and reduce burden of disease for CC (RCC and UCC) patients.

Cough hypersensitivity and chronic cough

Chronic cough is globally prevalent across all age groups. This disorder is challenging to treat because many pulmonary and extrapulmonary conditions can present with chronic cough, and cough can also be present without any identifiable underlying cause or be refractory to therapies that improve associated conditions. Most patients with chronic cough have cough hypersensitivity, which is characterized by increased neural responsivity to a range of stimuli that affect the airways and lungs, and other tissues innervated by common nerve supplies. Cough hypersensitivity presents as excessive coughing often in response to relatively innocuous stimuli, causing significant psychophysical morbidity and affecting patients' quality of life. Understanding of the mechanisms that contribute to cough hypersensitivity and excessive coughing in different patient populations and across the lifespan is advancing and has contributed to the development of new therapies for chronic cough in adults. Owing to differences in the pathology, the organs involved and individual patient factors, treatment of chronic cough is progressing towards a personalized approach, and, in the future, novel ways to endotype patients with cough may prove valuable in management.

Prevalence and burden of chronic cough in China: a national cross-sectional study

Background

Chronic cough is a common complaint, but there are no population-based data on its burden in China. We determined the prevalence of chronic cough and its impact on health status in adults stratified by sex, age and the diagnosis of COPD or the presence of small airway dysfunction (SAD).

Methods

A representative sample of 57 779 Chinese adults aged 20 years or older was recruited and pulmonary function test was measured. Chronic cough was defined as cough lasting for >3 months in each year. Quality of life was assessed by the 12-item Short Form Health Survey (SF-12), and self-reported history of hospital visits was recorded.

Results

Chronic cough was found in 3.6% (95% CI 3.1–4.1) of Chinese adults, 2.4% (95% CI 1.9–3.1) of those aged 20–49 years and 6.0% (95% CI 5.3–6.8) of those aged 50 years or older. Individuals with chronic cough had an impaired physical component summary (PCS) score of the SF-12 (p<0.0001) and more emergency visits (p=0.0042) and hospital admissions (p=0.0002). Furthermore, the impact of chronic cough on PCS score was more significant in those aged 50 years or older, or with COPD (p=0.0018 or 0.0002, respectively), with the impact on hospital admission being more significant in those with COPD or with SAD (p=0.0026 or 0.0065, respectively).

Conclusions

Chronic cough is prevalent in China and is associated with a poorer health status, especially in individuals aged 50 years or older and those with the diagnosis of COPD or SAD.

In the general adult population in China, chronic cough is prevalent and associated with poorer health status, especially in individuals aged ≥50 years and those with COPD or small airway dysfunctionhttps://bit.ly/3785LYZ

Past and Trends in Cough Sound Acquisition, Automatic Detection and Automatic Classification: A Comparative Review

Cough is a very common symptom and the most frequent reason for seeking medical advice. Optimized care goes inevitably through an adapted recording of this symptom and automatic processing. This study provides an updated exhaustive quantitative review of the field of cough sound acquisition, automatic detection in longer audio sequences and automatic classification of the nature or disease. Related studies were analyzed and metrics extracted and processed to create a quantitative characterization of the state-of-the-art and trends. A list of objective criteria was established to select a subset of the most complete detection studies in the perspective of deployment in clinical practice. One hundred and forty-four studies were short-listed, and a picture of the state-of-the-art technology is drawn. The trend shows an increasing number of classification studies, an increase of the dataset size, in part from crowdsourcing, a rapid increase of COVID-19 studies, the prevalence of smartphones and wearable sensors for the acquisition, and a rapid expansion of deep learning. Finally, a subset of 12 detection studies is identified as the most complete ones. An unequaled quantitative overview is presented. The field shows a remarkable dynamic, boosted by the research on COVID-19 diagnosis, and a perfect adaptation to mobile health.

Impact of mental health and personality traits on the incidence of chronic cough in the Canadian Longitudinal Study on Aging

Background

Chronic cough is a common troublesome condition, but risk factors for developing chronic cough are poorly understood. The aim of this study was to understand the relationship between mental health disorders, personality traits and chronic cough.

Methods

The Canadian Longitudinal Study on Aging is a prospective, nationally generalisable, random sample of adults aged 45-85 years at baseline recruited between 2011 and 2015, and followed-up 3 years later. Chronic cough was defined as a daily cough over the last 12 months. Incident chronic cough was defined as those participants who reported new-onset chronic cough between baseline and follow-up 1. Current depressive symptoms and psychological distress were assessed using the Center for Epidemiologic Study Short Depression Scale (CESD-10) and Kessler Psychological Distress Scale (K-10), respectively. The "Big Five" personality traits were assessed using the Ten-Item Personality Inventory. Relative risks are reported using a multivariate mutually adjusted model.

Results

At follow-up 1, 2506 participants (11.1%) reported new-onset chronic cough during the ∼3-year interval. Depressive symptoms (CESD-10 ≥10: relative risk 1.22 (95% CI 1.03-1.44)) and psychological distress (K-10 ≥22: relative risk 1.20 (95% CI 1.07-1.36)) at baseline were both independent predictors of a higher risk of incident chronic cough. Prevalent and incident chronic cough were also independently associated with an increased risk of developing depressive symptoms and psychological distress. Personality traits did not influence the development of chronic cough but did increase the risk of depressive symptoms and psychological distress.

Conclusions

This study shows that there is a bidirectional relationship between chronic cough, and depressive symptoms and psychological distress, and personality traits do not independently influence the development of chronic cough.

Cough in the Elderly During the COVID-19 Pandemic

INTRODUCTION

The prevalence of chronic cough increases with age. However, data on the prevalence and background disorders of cough subtypes in the elderly are scarce. The objective of this study was to identify the point prevalence and risk factors of acute, subacute, and chronic cough in an elderly community-based population.

METHODS

This was a cross-sectional email survey amongst 26,205 members of the Finnish Pensioners' Federation during the COVID-19 pandemic in spring 2021.

RESULTS

The response rate was 23.6% (6189). 5983 subjects aged at least 64 years were included in the analyses (mean 72.6 years, 66.3% female). The point prevalence of daily acute, subacute, and chronic cough were 1.4%, 0.7%, and 9.6%, respectively. Only 0.4% of the subjects had a COVID-19 infection. In the multivariate analyses, chronic rhinosinusitis, and obstructive sleep apnoea were common risk factors for all cough subtypes. Chronic cough had several risk factors; Bronchiectasis (OR 5.79 (CI95% 2.70-12.41)), current asthma (2.67 (2.02-3.54)), chronic rhinosinusitis (2.51 (1.94-3.24)), somatic symptom score (1.13 per symptom (1.07-1.19)), family history of chronic cough (1.88 (1.54-2.30)), gastro-oesophageal reflux disease (1.86 (1.50-2.32)), advanced age (1.20 per decade (1.02-1.40)), chronic obstructive pulmonary disease (1.74 (0.99-3.05)), dog ownership (1.42 (1.07-1.89)), and obstructive sleep apnoea (1.41 (1.16-1.73)).

CONCLUSION

Acute and subacute cough, as well as previous COVID-19 infection, were uncommon in this Finnish elderly population. The prevalence of chronic cough was higher than that previously found in younger adults. Chronic cough is a multifactorial disorder in the elderly.

The interrelationship of chronic cough and depression: a prospective population-based study

Background

Chronic cough is a debilitating medical condition that is often complicated by psychomorbidities such as depressive symptoms. Nevertheless, little is known about the impact of chronic cough on the risk of developing depression. Therefore, we investigated the association between chronic cough and prevalent, incident and recurrent depression in a population-based sample of middle-aged and older persons.

Methods

Within the Rotterdam Study, a population-based cohort, we defined chronic cough as reporting daily coughing for ⩾3 months. Depression was assessed using the Center for Epidemiologic Studies Depression scale, clinical interviews and medical records. Associations between chronic cough and depression were determined with linear, logistic and Cox regression analyses.

Results

The study included 5877 participants (mean±sd age 72±8 years, 59% female) who contributed 37 287 person-years of follow-up. At baseline, participants with chronic cough reported more depressive symptoms (adjusted standardised mean difference 0.15, 95% CI 0.07–0.22) compared to those without chronic cough. Over time, chronic cough was associated with an increased risk of depression in participants with a history of depression (hazard ratio (HR) 1.45, 95% CI 1.13–1.84), but not in those without a history of depression (HR 0.91, 95% CI 0.68–1.22).

Conclusions

Adults with chronic cough have a disproportionate burden of depressive symptoms and an increased risk of recurrent depression. This highlights the importance of screening for depression in patients with chronic cough.

Adults with chronic cough have a disproportionate burden of depressive symptoms and are more likely to suffer recurrent depression, highlighting the need for screening for depression in individuals with chronic coughhttps://bit.ly/3sPvYTd

Language and Geographical Location influences the Incidence of Chronic Cough in the Canadian Longitudinal Study on Aging (CLSA)

The prevalence of chronic cough is highly variable globally ranging from 2% to 18% [1]. The prevalence was higher in Australia, Europe, America (11–18%) and much lower in Asia (4%) and Africa (2%), even after adjusting for smoking. The majority of the studies used the 3-month chronic bronchitis definition, but even in studies using the same 8-week cut-off, variations still persist: UK (12%) [2], Finland (7.2%) [3], Germany (5%) [4], Denmark (4%) [5], South Korea (2.6%) [6], Japan (2.2%) [7], Nigeria (1.1%) [8]. The reasons for these variations, even in geographically similar countries, are unclear.

French speakers have a 4% lower incidence of chronic cough than English speakers in the CLSA, but English speakers from Quebec, Newfoundland and Labrador, and Nova Scotia also have a lower risk of developing chronic coughhttps://bit.ly/3qAd3Mf

Chronic cough in Germany: results from a general-population survey

Background

Chronic cough (CC) which is defined ≥8 weeks is a common condition in clinical practice. However, estimates of prevalence and associated comorbidities in German adults and key subgroups of age and gender are lacking.

Methods

Cross-sectional study based on a representative panel of 15 020 adult subjects of the general population who completed the German National Health and Wellness Survey, reporting CC and questions about comorbidities. Lifetime and 12-month prevalence are presented as unweighted estimates.

Results

The lifetime CC prevalence was 6.5% (range across age groups 5.1%-8.3%) and the 12-month prevalence was 4.9% (range 3.7-5.7%). The prevalence of diagnosed CC was 2.8% (range 0.9-4.1%) and the prevalence of persons currently on any prescription to treat CC was 0.6% (range 0.2-1.4%). Respondents who experienced CC were 52.0±17.0 years old, with a higher prevalence in those aged 50 years and older. Persons with CC had higher morbidity scores and were diagnosed with an increased number of comorbidities, most frequently diagnoses of the respiratory system (71.0%), followed by digestive tract disorders (34.0%) and sleep disorders (37.6%).

Conclusions

In a broadly representative sample of German adults, lifetime and 12-month prevalence of CC was greatest in current and former smokers and those older ≥50 years of age. Comorbidities are frequent and may complicate management of these patients.

Leicester Cough Questionnaire validation and clinically important thresholds for change in refractory or unexplained chronic cough

INTRODUCTION

The Leicester Cough Questionnaire (LCQ), a cough-specific quality-of-life measure, evaluates the impact of cough across physical, psychological, and social domains in patients with chronic cough (CC). This study assessed the psychometric properties of the LCQ.

METHODS

Data from a phase IIb, randomized controlled trial of the P2X3-receptor antagonist gefapixant were analyzed (NCT02612610). Subjective [Cough Severity Diary, cough severity visual analogue scale, and patient global impression of change (PGIC)] and objective (awake and 24-h cough frequency) data were used to validate the LCQ for use in patients with refractory or unexplained CC (RCC and UCC, respectively). Psychometric analyses included confirmatory factor analyses, internal consistency and test-retest reliability, validity, responsiveness, and estimated within-patient thresholds for clinically meaningful change.

RESULTS

Model-fit values for the proposed three-factor LCQ domains and most individual items were acceptable. Analyses suggest that a mean improvement ranging from 1.3 to 2.3 points for the LCQ total and ⩾0.8, ⩾0.9, and ⩾0.8 points for physical, psychological, and social domain scores, respectively, had the best sensitivity and/or specificity for predicting patient ratings of improvement on the PGIC.

CONCLUSIONS

The LCQ is a valid and reliable measure to evaluate cough-specific quality of life and is a fit-for-purpose measure for use in patients with RCC or UCC. Although a single threshold for defining clinically meaningful change depends on the context of use, the results can help guide both treatment decisions and drug development. Therefore, clinicians may consider a ⩾1.3-point increase in the LCQ total score as clinically meaningful.

Distribution of chronic cough phenotypes in the general population: A cross-sectional analysis of the LEAD cohort in Austria

RATIONALE

Recent guidelines consider chronic cough to be a unique clinical entity with different phenotypes. We aimed to investigate them in a general population and to describe prevalence, distribution, and characteristics of these phenotypes within the Austrian general population.

METHODS

From the LEAD study, a longitudinal observational population-based cohort, data from questionnaires and spirometry of 10,057 adult participants was analysed. Chronic cough was defined as coughing nearly every day during the last 12 months for at least 3 months (>12 weeks).

RESULTS

The prevalence of chronic cough was 9% and increased with age. We found no sex predominance but a female preponderance (68%) in never smokers. A presumable cause was identified in 85% of which more than half (53.9%) had two phenotypes, 36.9% belonged to one only and 9.2% to three or more. Regarding the distribution of phenotypes, 40.8% were current smokers, 32.6% had an ACE inhibitor intake, 18.2% GERD, 17.6% asthmatic cough, 9.7% UACS and 28.3% other diseases associated with chronic cough. 15% had unexplained chronic cough with no identifiable phenotype. Current smoking, low socioeconomic status, obesity, COPD and obstructive sleep apnea were associated factors with chronic cough.

CONCLUSION

Chronic cough is common among adults in Austria and highly prevalent in the older population. Most participants can be phenotyped with simple questionnaire-based assessment and can therefore potentially receive specific treatment without intensive clinical workup.

WAO-ARIA consensus on chronic cough - Part II: Phenotypes and mechanisms of abnormal cough presentation - Updates in COVID-19

BACKGROUND

Chronic cough can be triggered by respiratory and non-respiratory tract illnesses originating mainly from the upper and lower airways, and the GI tract (ie, reflux). Recent findings suggest it can also be a prominent feature in obstructive sleep apnea (OSA), laryngeal hyperresponsiveness, and COVID-19. The classification of chronic cough is constantly updated but lacks clear definition. Epidemiological data on the prevalence of chronic cough are informative but highly variable. The underlying mechanism of chronic cough is a neurogenic inflammation of the cough reflex which becomes hypersensitive, thus the term hypersensitive cough reflex (HCR). A current challenge is to decipher how various infectious and inflammatory airway diseases and esophageal reflux, among others, modulate HCR.

OBJECTIVES

The World Allergy Organization/Allergic Rhinitis and its Impact on Asthma (WAO/ARIA) Joint Committee on Chronic Cough reviewed the current literature on classification, epidemiology, presenting features, and mechanistic pathways of chronic cough in airway- and reflux-related cough phenotypes, OSA, and COVID-19. The interplay of cough reflex sensitivity with other pathogenic mechanisms inherent to airway and reflux-related inflammatory conditions was also analyzed.

OUTCOMES

Currently, it is difficult to clearly ascertain true prevalence rates in epidemiological studies of chronic cough phenotypes. This is likely due to lack of standardized objective measures needed for cough classification and frequent coexistence of multi-organ cough origins. Notwithstanding, we emphasize the important role of HCR as a mechanistic trigger in airway- and reflux-related cough phenotypes. Other concomitant mechanisms can also modulate HCR, including type2/Th1/Th2 inflammation, presence or absence of deep inspiration-bronchoprotective reflex (lower airways), tissue remodeling, and likely cough plasticity, among others.

Validation of a visual analog scale for assessing cough severity in patients with chronic cough

Introduction:

Patients with chronic cough experience considerable burden. The cough severity visual analog scale (VAS) records patients’ assessment of cough severity on a 100-mm linear scale ranging from “no cough” (0 mm) to “worst cough” (100 mm). Although cough severity scales are widely used in clinical practice and research, their use in patients with refractory or unexplained chronic cough has not been formally validated.

Methods:

This analysis includes data from a phase 2b randomized controlled trial of the P2X3-receptor antagonist gefapixant for treatment of refractory or unexplained chronic cough (NCT02612610). Cough severity VAS scores were assessed at baseline and Weeks 4, 8, and 12. The cough severity VAS was validated using several outcomes, including the Cough Severity Diary (CSD), Leicester Cough Questionnaire (LCQ), patient global impression of change (PGIC) scale, and objective cough frequency. Validation metrics included test–retest reliability, convergent and known-groups validity, responsiveness, and score interpretation (i.e., clinically meaningful change threshold).

Results:

The analysis included 253 patients (median age, 61.0 years; females, 76%). Test–retest reliability of the cough severity VAS was moderate (intraclass correlation coefficient, 0.51). The cough severity VAS had acceptable convergent validity with other related measures (Pearson r of 0.53 and -0.41 for CSD and LCQ total scores, respectively; p < 0.0001 for each). Known-groups validity was supported by significant differences in mean cough severity VAS scores across severity groups defined using CSD, LCQ, and cough frequency tertiles. A large effect size was observed in patients with the greatest improvements in PGIC (Cohen d = -1.8). A ⩾ 30-mm reduction in the cough severity VAS was estimated as a clinically meaningful change threshold for clinical trials in chronic cough.

Conclusions:

The cough severity VAS is a valid and responsive measure. A cough severity VAS reduction of ⩾ 30 mm can discriminate clinically meaningful changes in chronic cough severity in clinical studies.

Risk factors for chronic cough in adults: A systematic review and meta-analysis

Despite the challenges of diagnosing and managing adult patients with chronic cough, a systematic synthesis of evidence on aetiological risk factor is lacking. We systematically searched PubMed and EMBASE to synthesize the current evidence for longitudinal associations between a wide range of risk factors and chronic cough in the general adult population, following the meta-analysis of observational studies in epidemiology (MOOSE) guidelines. The Newcastle-Ottawa scale was used to assess the quality of the included studies. Fixed-effect meta-analysis was conducted where appropriate. Of 26 eligible articles, 16 domains of risk factors were assessed. There was consistent evidence that asthma (pooled adjusted OR [aOR] = 3.01; 95% CI: 2.33-3.70; I²  = 0%; number of articles [N] = 3) and low education levels/socioeconomic status (SES) (pooled aOR = 1.46; 95% CI: 1.20-1.72; I²  = 0%; N = 3) were associated with an increased risk of chronic cough after adjusting for smoking and other confounders. While continuous smoking was associated with chronic cough (aOR = 1.81; 95% CI: 1.36-2.26; I²  = 57%; N = 3), there was too little evidence to draw conclusions for occupational exposures, outdoor air pollution, early-life exposures, diet, snoring and other chronic conditions, including obesity, chronic obstructive pulmonary disease, gastro-oesophageal reflux disease and chronic pain. Asthma, persistent smoking and lower education/SES were associated with an increased risk of chronic cough. Longitudinal associations between other factors frequently mentioned empirically (i.e., occupational exposures, air pollution and chronic respiratory conditions) need further investigation, ideally with objective and standardized measurement.

Epidemiology of adult chronic cough: disease burden, regional issues, and recent findings

Chronic cough is a common medical condition that has a significant impact on patients' quality of life. Although it was previously considered a symptom of other disorders, it is now regarded as a pathologic state that is characterized by a deviation from the intrinsic protective functions of the cough reflex, especially in adults. There are several factors that may underlie the cough reflex hypersensitivity and its persistence, such as age, sex, comorbidities, viral infection, exposure to irritants or environmental pollutants, and their interactions may determine the epidemiology of chronic cough in different countries. With a deeper understanding of disease pathophysiology and advanced research methodology, there are more attempts to investigate cough epidemiology using a large cohort of healthcare population data. This is a narrative overview of recent findings on the disease burden, risk factors, Asia-Pacific issues, and longitudinal outcomes in adults with chronic cough. This paper also discusses the approaches utilizing routinely collected data in cough research.

Prevalence and Burden of Chronic Cough in the United States

BACKGROUND

Chronic cough is a common complaint but there are little population-based data on its burden in the United States.

OBJECTIVE

To determine the prevalence of chronic cough and its burden on individuals and the health care system.

METHODS

This was a survey of respondents who completed the 2018 National Health and Wellness Survey and questions about sleep and health care resource use. Chronic cough was defined as having a daily cough for 8 or more weeks. Respondents without chronic cough were selected through propensity score matching. Chronic cough prevalence was estimated using poststratification sampling weights calculated using U.S. Census data and post-data Horvitz-Thompson sampling weights to adjust for sampling bias.

RESULTS

Of 74,977 National Health and Wellness Survey respondents, 3,654 had experienced chronic cough in the previous 12 months, for a weighted prevalence of 5.0%. Respondents with chronic cough were older and more predominantly female than respondents without chronic cough (both P < .001). Compared with matched respondents without chronic cough, those with chronic cough had lower mean scores on the Medical Outcomes Study 36-item Short Form Survey v2 physical (P < .001) and mental (P < .001) component summary scores. More respondents with chronic cough than matched controls experienced severe anxiety and severe depression in the past 2 weeks, work productivity impairment, impaired sleep quality and daytime sleepiness, as well as more emergency department visits and hospitalizations in the past 6 months (P < .001 for all comparisons).

CONCLUSIONS

The burden of chronic cough manifests itself as reduced health-related quality of life, increased anxiety and depression, impaired sleep and work productivity, and greater health care utilization.

Risk and impact of chronic cough in obese individuals from the general population

BACKGROUND

Obese individuals may be at higher risk of chronic cough. We investigated the risk and impact of chronic cough in obese individuals from the general population.

METHODS

We recorded chronic cough, body mass index (BMI) and other related clinical conditions in 44 554 adults from the Copenhagen General Population Study. Individuals with asthma and/or chronic obstructive pulmonary disease were excluded (n=10 977). BMI was divided into: underweight (BMI <18.5 kg/m²), normal weight (18.5-24.9 kg/m²), overweight (25.0-29.9 kg/m²), obese (30.0-34.9 kg/m²) and severely obese (≥35.0 kg/m²).

RESULTS

Among 33 577 adults from the general population, 27 829 (83%) were non-obese and 5748 (17%) were obese. Compared with individuals with normal weight, multivariable adjusted ORs for chronic cough risk were 1.4 (95% CI 1.2 to 1.6) in overweight, 1.9 (95% CI 1.7 to 2.2) in obese and 2.6 (95% CI 2.1 to 3.2) in severely obese individuals. Mediation analyses showed that chronic cough due to obesity was up to 23% mediated by gastro-oesophageal reflux disease (GERD). Other mediators included low vegetable intake with 10% and occupational exposure with 8%. Among obese individuals, those with versus without chronic cough had worse accompanying respiratory symptoms, more often comorbidities including GERD and diabetes, greater healthcare utilisations, lower lung function and higher blood inflammation (all p<0.05).

CONCLUSION

There is dose-response relationship between BMI and chronic cough, and chronic cough risk is twofold to threefold higher in obese individuals from the general population. This increased risk was partly mediated by GERD, low vegetable intake and occupational exposure, supporting that there may be benefit to gain by ameliorating some of these factors in obese individuals with chronic cough.

Is there clinical value in performing capsaicin cough challenges in patients with severe asthma?

Over 330 million people have been diagnosed with asthma worldwide [1], of whom 5–10% are classified as severe [2]. Despite use of high doses of inhaled corticosteroids (ICS), long-acting bronchodilators (LABA) and/or maintenance oral steroid use, patients with severe asthma account for over 50% of the asthma healthcare budget [3, 4]. Largely due to exacerbations requiring hospitalisation, and cost of treatments to control disease severity, the disease burden has serious implications for their health and quality of life [3–5].

Heightened capsaicin cough sensitivity is independently associated with poor asthma control in moderate-to-severe asthma patientshttps://bit.ly/3mkbLkI

The interrelatedness of chronic cough and chronic pain

Since chronic cough has common neurobiological mechanisms and pathophysiology with chronic pain, both clinical disorders might be interrelated. Hence, we examined the association between chronic cough and chronic pain in adult subjects in the Rotterdam Study, a large prospective population-based cohort study.Using a standardised questionnaire, chronic pain was defined as pain lasting up to 6 months and grouped into a frequency of weekly/monthly or daily pain. Chronic cough was described as daily coughing for at least 3 months duration. The longitudinal and cross-sectional associations were investigated bi-directionally.Of 7141 subjects in the study, 54% (n=3888) reported chronic pain at baseline. The co-prevalence of daily chronic pain and chronic cough was 4.4%. Chronic cough was more prevalent in subjects with daily and weekly/monthly chronic pain compared with those without chronic pain (13.8% and 10.3% versus 8.2%; p<0.001). After adjustment for potential confounders, prevalent chronic pain was significantly associated with incident chronic cough (OR 1.47, 95% CI 1.08-1.99). The association remained significant in subjects with daily chronic pain (OR 1.49, 95% CI 1.06-2.11) with a similar effect estimate, albeit non-significant in those with weekly/monthly chronic pain (OR 1.43, 95% CI 0.98-2.10). After adjustment for covariables, subjects with chronic cough had a significant risk of developing chronic pain (OR 1.63, 95% CI 1.02-2.62) compared with those without chronic cough.Chronic cough and chronic pain confer risk on each other among adult subjects, indicating that both conditions might share common risk factors and/or pathophysiologic mechanisms.

Addressing unmet needs for diagnosis and management of chronic cough in the primary care setting

Chronic cough (i.e. cough lasting >8 weeks) has a global prevalence of approximately 10% and is associated with substantial patient burden, including social, psychological, and physical impairments. This burden can be long-lasting, with some patients experiencing cough for many years. Although chronic cough is often a symptom of respiratory diseases (e.g. interstitial lung disease, chronic obstructive pulmonary disease) or is associated with comorbid conditions (e.g. asthma, gastroesophageal reflux disease) and may resolve after targeted treatment of these conditions, some patients continue to cough despite optimal treatment of associated conditions (refractory chronic cough (RCC)) or have no identifiable conditions presumed to be contributing to the cough (unexplained chronic cough (UCC)). As both RCC and UCC are diagnoses of exclusion, it is critical to perform a thorough initial patient assessment with adherence to diagnostic guidelines to accurately identify RCC and UCC and provide appropriate treatment. Primary care physicians may be in an important position to provide the initial diagnostic workup of patients with chronic cough as well as identify when referral to specialists (e.g. pulmonologists, allergists, otolaryngologists) is appropriate. In this narrative review, current diagnosis and management guidelines for chronic cough are summarized and recommendations for diagnostic workup in a primary care setting are provided. Increased appreciation of chronic cough as a distinct condition, rather than as only a symptom of other diseases, may help overcome current challenges in diagnosing and managing chronic cough and reduce patient burden.

Prevalence, incidence and characteristics of chronic cough among adults from the Canadian Longitudinal Study on Aging

The global prevalence of chronic cough is highly variable, ranging from 2% to 18%. There is a lack of data on the prevalence and incidence of chronic cough in the general population. The objective of this study was to investigate the prevalence and incidence of chronic cough in a sample of Canadian adults, and how these are influenced by age, sex, smoking, respiratory symptoms, medical comorbidities and lung function. Participants with chronic cough were identified from the Canadian Longitudinal Study on Aging (CLSA) based on self-reported daily cough in the past 12 months. This is a prospective, nationally generalisable, stratified random sample of adults aged 45-85 years at baseline recruited between 2011 and 2015, and followed-up 3 years later. The prevalence and incidence per 100 person-years are described, with adjustments for age, sex and smoking. Of the 30 097 participants, 29 972 completed the chronic cough question at baseline and 26 701 did so at follow-up. The prevalence of chronic cough was 15.8% at baseline and 17.6% at follow-up with 10.4-17.1% variation across seven provinces included in the CLSA comprehensive sample. Prevalence increased with age and current smoking, and was higher in males (15.2%), Caucasians (14%) and those born in North America, Europe or Oceania (14%). The incidence of chronic cough adjusted for age, sex and smoking was higher in males and in underweight and obese subjects. Subjects with respiratory symptoms, airway diseases, lower forced expiratory volume in 1 s (% predicted), cardiovascular diseases, psychological disorders, diabetes and chronic pain had a higher incidence of chronic cough. The prevalence and incidence of chronic cough is high in the CLSA sample with geographic, ethnic and gender differences, influenced by a number of medical comorbidities.