Prevalence of chronic cough and possible causes in the general population based on the Korean National Health and Nutrition Examination Survey

Clinical Aspects of Chronic Idiopathic Postnasal Drip: An Entity Not to Be Overlooked

BACKGROUND/AIM

Postnasal drip may be related to several diseases, but not all patients are clearly diagnosed. Patients with chronic, idiopathic postnasal drip symptoms are easily overlooked, and their clinical features are yet to be identified. This study aimed to analyze the clinical features and response to first generation antihistamine-decongestant therapy in patients with chronic idiopathic postnasal drip, suggesting it as a distinct entity.

PATIENTS AND METHODS

A retrospective cohort study involving 157 chronic idiopathic postnasal drip patients was conducted, analyzing demographics, symptoms, and treatment response to first-generation antihistamines and nasal decongestants.

RESULTS

Mean age of patients was 55.4±17.0 years old. Median duration of symptom was 36 months (range=12-66 months) and severity in the visual analogue scale was 7 (range=5-8). Throat discomfort was the most frequently associated symptom (73.7%). Cough was recorded in 30.3% of patients. Viscosity of postnasal drip was associated with rhinorrhea and throat discomfort. Of the patients, 71.6% responded positively to 1st generation antihistamine-decongestant medication. However, 25.9% of patients presented symptom re-occurrence. Patients with nasal stiffness or persistent symptoms presented a higher re-occurrence rate compared to others.

CONCLUSION

This study outlines the clinical features of patients with chronic idiopathic postnasal drip and suggests it as a distinctive entity., This proposal aims to enhance diagnostic precision and promote further research in the field.

First Exploration of the Altered Microbial Gut-Lung Axis in the Pathogenesis of Human Refractory Chronic Cough

PURPOSE

Cough represents a natural mechanism that plays an important defensive role in the respiratory tract, but in some conditions, it may become persistent, nonproductive, and harmful. In general, refractory chronic cough (RCC) occurs in about 20% of individuals; hence, we aimed to assess the presence of altered gut-lung communication in RCC patients through a compositional and functional characterization of both gut (GM) and oral microbiota (OM).

METHODS

16S rRNA sequencing was used to characterize both GM and OM composition of RCC patients and healthy controls (HC). PICRUST2 assessed functional changes in microbial communities while gas chromatography was used to evaluate fecal short-chain fatty acid levels and serum-free fatty acid (FFA) abundances.

RESULTS

In comparison with HC, RCC patients reported increased saliva alpha-diversity and statistically significant beta-diversity in both GM and OM. Also, a, respectively, significant increased or reduced Firmicutes/Bacteroidota ratio in stool and saliva samples of RCC patients has been shown, in addition to a modification of the abundances of several taxa in both GM and OM. Moreover, a potential fecal over-expression of lipopolysaccharide biosynthesis and lipoic acid metabolism pathways and several differences in serum FFA levels have been reported in RCC patients than in HC.

CONCLUSION

Since differences in both GM and OM of RCC patients have been documented, these findings could provide new information about RCC pathogenesis and also pave the way for the development of novel nutritional or pharmacological interventions for the management of RCC through the restoration of eubiotic gut-lung communication.

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.

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.

The Efficacy of Superior Laryngeal Nerve Block for Neurogenic Cough: A Placebo-Controlled Trial

OBJECTIVES

Chronic cough is a common and debilitating problem. The objective of this study is to assess the efficacy and safety of superior laryngeal nerve (SLN) block for neurogenic cough through a placebo-controlled, prospective trial.

METHODS

Patients were recruited in an outpatient tertiary care center. Inclusion criteria included a history consistent with neurogenic cough and age ≥ 18. Exclusion criteria included patients with untreated other etiologies of chronic cough (i.e., uncontrolled reflux) and current neuromodulating medication use. Patients were randomized into the treatment (1-2 mL of a 1:1 triamcinolone 40 mg: 1% lidocaine with 1:200,000 epinephrines) or placebo (saline) group and received two unilateral injections at approximately 2-week intervals. Outcomes were measured primarily by the Leicester Cough Questionnaire (LCQ) and a patient symptom log including a visual analog scale of cough severity.

RESULTS

17 patients completed the study, including 10 in the treatment group and seven in the placebo group. Eight (80%) patients in the treatment group reported improvement with at least one of the injections, whereas only 1 (14.3%) patient reported improvement in the placebo group (p < 0.0001). Average total LCQ scores increased in the treatment group from 10.09 to 13.15 (p = 0.03), with the most change occurring in the social domain. There was no statistically significant change in LCQ scores for the placebo group. There were no serious adverse events.

CONCLUSION

An SLN block is a safe and efficacious procedure for the treatment of neurogenic cough. Further studies are needed to optimize treatment protocol and assess long-term follow-up of patient outcomes.

LEVEL OF EVIDENCE

2 Laryngoscope, 133:3068-3074, 2023.

Risk Factors for Persistent Chronic Cough During Consecutive Years: A Retrospective Database Analysis

BACKGROUND

The identification of patients at high risk for diseases provides clinicians essential information to better manage such patients. Persistent chronic cough (PCC) is a condition with high clinical burden and limited knowledge of the risk factors that drive the persistent symptoms.

OBJECTIVE

To understand the risk factors of PCC in patients with CC diagnosed by specialists.

METHODS

In this retrospective study, adults aged 18 to 85 years diagnosed with CC by a pulmonologist, allergist, otolaryngologist, or gastroenterologist in the period 2011 to 2016 were identified. PCC was defined by another CC code or at least 2 cough events at least 8 weeks but no more than 4 months apart in each of the 2 consecutive years beginning 1 year after the original CC diagnosis. Unadjusted and adjusted risk ratios with 95% CI for patient characteristics at baseline in relationship to PCC were estimated by Poisson regression models with robust error variance.

RESULTS

Of the adults with CC, 3270 (27.4%) had PCC and 5302 (44.5%) did not have CC during follow-up; 3341 (28.1%) had CC in only 1 follow-up year and were excluded from the analysis. Compared with patients without PCC, patients with PCC were noted to have significantly increased adjusted risk ratios for the following baseline features: (1) demographic characteristics (elderly, females, and less educated); (2) comorbidities (chronic obstructive pulmonary disease, chronic sinusitis, bronchiectasis, pulmonary fibrosis, hypertension, depression, and cough complications); (3) medication dispensed (inhaled corticosteroids/long-acting beta-agonists, leukotriene modifiers, nasal corticosteroids, nasal short-acting muscarinic antagonists, proton pump inhibitors, antitussives with narcotics, and neuromodulators); and (4) specialist care, particularly with pulmonologists.

CONCLUSIONS

Knowledge of the independent risk factors associated with PCC should aid clinicians in identifying such patients and improve their management.

Cough Characteristics and Healthcare Journeys of Chronic Cough Patients in Community-Based Populations in South Korea and Taiwan

PURPOSE

This study aimed to understand the cough characteristics and health journeys among community-based chronic cough (CC) patients, and their characteristics associated with healthcare visits.

METHODS

A population-based cross-sectional study was conducted in 2020, using the South Korea and Taiwan National Health and Wellness Survey (NHWS) and CC surveys. Patients with current CC were defined by daily coughing for > 8 weeks in the past 12 months and currently coughing at the time of survey. The survey items pertained to CC patients' treatment journey and cough characteristics.

RESULTS

Patients with current CC in South Korea and Taiwan, respectively, had cough duration for 3.45 ± 5.13 years and 5.75 ± 7.28 years and cough severity visual analogue scale (VAS) scores of 4.50 ± 2.15 and 4.46 ± 1.92 out of 0-10 scale, with 70.3% and 57.9% having spoken with a physician about cough. Compared to CC patients who had not visited healthcare professionals for cough, those who visited reported more severe cough (VAS: 3.89 ± 1.71 vs. 4.6 ± 2.02; p = 0.009), worse cough-specific quality of life (Leicester Cough Questionnaire: 16.20 ± 3.23 vs.13.45 ± 2.68, p < 0.001), greater symptom severity (Hull Airway Reflux Questionnaire: 16.73 ± 15.16 vs. 24.57 ± 13.38; p < 0.001), and more urinary incontinence (13.6 vs. 26.5%, p = 0.027). More than 50% of patients perceived cough medication(s) as not or a little useful and 25% felt their physicians did not well understand how CC impacts their life.

CONCLUSION

Cough is frequently severe and persistent among community-based CC patients. They experience several issues in their health journey, including treatment ineffectiveness and physician's understanding. Further efforts are warranted to reduce CC burden in the community.

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.

Upper airway cough syndrome may be the main cause of chronic cough in Japan: a cohort study

BACKGROUND

Upper airway cough syndrome (UACS) is generally considered a common cause of chronic cough but remains poorly recognised in Japan.

OBJECTIVE

This study aimed to assess whether UACS was a common cause of chronic cough in Japan, as is true in other countries. Interview and examination items were evaluated for their potential use in UACS diagnosis.

METHODS

All patients with chronic cough were preliminarily diagnosed with bronchial asthma, UACS, gastroesophageal reflux disease, or postinfectious prolonged cough, based on interviews and examinations. Treatment centred on nasal steroids was administered to the UACS group and standard treatment to the other groups. The observation period lasted 4 weeks. The subjective cough score at first diagnosis was set at 10, and the final diagnosis was made based on the treatment administered at the time the cough score had decreased to ≤2. The associations between the presence or absence of UACS and interview and examination items were statistically evaluated.

RESULTS

Among 230 patients with chronic cough, 146 were diagnosed with UACS-only. Multivariate logistic regression revealed that the assessment items 'awareness of mucus accumulating in the back of the throat', 'presence of abnormal echography findings', 'absence of associated coughing when exercising' and 'presence of coughing persisting after onset' were significantly correlated with the presence or absence of UACS (p < 0.05).

CONCLUSIONS

UACS may be the most common cause of chronic cough in Japan and may be effectively treated with nasal corticosteroids. Diagnosing UACS might be possible by selecting appropriate interview and examination items.

Irritant-Induced Chronic Cough Triggers: A Scoping Review and Clinical Checklist

Purpose The primary aim of this review was to identify environmental irritants known to trigger chronic cough through the life span and develop a comprehensive clinically useful irritant checklist. Method A scoping review was conducted using the Preferred Reporting Items for Systematic Review and Meta-Analysis Extension for Scoping Reviews, checklist, and explanation. English-language, full-text resources were identified through Medline, PsycINFO, SPORTDiscus, Web of Science, and ProQuest Dissertations and Theses Global. Results A total of 1,072 sources were retrieved; of these, 109 were duplicates. Titles of abstracts of 963 articles were screened, with 295 selected for full-text review. Using the exclusion and inclusion criteria listed, 236 articles were considered eligible and 214 different triggers were identified. Triggers were identified from North America, Europe, Africa, Asia, and Australia. Occupational exposures were also delineated. Conclusions A clinically useful checklist of both frequently encountered triggers and idiosyncratic or rare triggers was developed. The clinical checklist provides a unique contribution to streamline and standardize clinical assessment of irritant-induced chronic cough. The international scope of this review extends the usefulness of the clinical checklist to clinicians on most continents.

Differential features of chronic cough according to etiology and the simple decision tree for predicting causes

Finding etiology of chronic cough is an essential part of treatment. Although guidelines include many laboratory tests for diagnosis, these are not possible in many primary care centers. We aimed to identify the characteristics and the differences associated with its cause to develop a clinical prediction model. Adult subjects with chronic cough who completed both Korean version of the Leicester Cough Questionnaire (K-LCQ) and COugh Assessment Test (COAT) were enrolled. Clinical characteristics of each etiology were compared using features included in questionnaires. Decision tree models were built to classify the causes. A total of 246 subjects were included for analysis. Subjects with asthma including cough variant asthma (CVA) suffered from more severe cough in physical and psychological domains. Subjects with eosinophilic bronchitis (EB) presented less severe cough in physical domain. Those with gastro-esophageal reflux disease (GERD) displayed less severe cough in all 3 domains. In logistic regression, voice hoarseness was an independent feature of upper airway cough syndrome (UACS), whereas female sex, tiredness, and hypersensitivity to irritants were predictors of asthma/CVA; less hoarseness was a significant feature of EB, and feeling fed-up and hoarseness were less common characteristics of GERD. The decision tree was built to classify the causes and the accuracy was relatively high for both K-LCQ and COAT, except for UACS. Voice hoarseness, degree of tiredness, hypersensitivity to irritants and feeling fed-up are important features in determining the etiologies. The decision tree may further assists classifying the causes of chronic cough.

Gender Differences in Chronic Obstructive Pulmonary Disease Symptom Clusters

Purpose

Previous research has indicated that female and male patients may experience different levels of symptoms. However, no studies of chronic obstructive pulmonary disease (COPD) patients have compared the number and types of symptom clusters identified in male and female patients. Therefore, the purpose of this study was to investigate gender differences in symptom clusters among COPD patients.

Patients and Methods

A total of 371 eligible patients were enrolled in the study. We assessed nine COPD symptoms, namely, dyspnea, cough, sputum, chest tightness, sleep quality, fatigue, frailty, anxiety, and depression. Exploratory factor analyses were used to explore the underlying clusters of the COPD symptoms.

Results

Underlying the nine symptoms, female patients had 2 clusters, and male patients had 3 clusters. Specifically, the three general symptoms poor sleep, fatigue, and frailty loaded on the same symptom cluster with anxiety and depression in female patients, while the same 3 general symptoms loaded on the same symptom cluster with chest tightness and dyspnea in male patients. Moreover, cough and sputum not only were more common in male patients but also loaded together on a separate symptom cluster.

Conclusion

Our findings suggest that in order to improve fatigue, frailty, and poor sleep quality, symptom management strategies should more closely address anxiety and depression in female patients as well as chest tightness and dyspnea in male patients. Smoking cessation is particularly important in male COPD patients because they account for a much higher proportion of smokers and are more likely to have cough and sputum. These findings signify the importance of identifying and implementing gender-tailored symptom management strategies to relieve symptom burden in COPD patients to enhance their quality of life.

Patient-Reported Burden of Chronic Cough in a Managed Care Organization

BACKGROUND

The burden of chronic cough (CC) requires better understanding.

OBJECTIVE

To determine the severity, health status, and health care resource utilization among patients with CC identified by electronic health records on 2 visits separated by ≥1 year.

METHODS

Information on cough-related burden was collected through survey from patients with CC, including validated questionnaires (the cough health status Leicester Cough Questionnaire [LCQ], the cough hypersensitivity Hull Airway Reflux Questionnaire [HARQ], and the Cough Quality of Life Questionnaire [CQLQ]), CC-associated respiratory and gastrointestinal comorbidities, and treatment responses. Spearman correlation coefficients were reported to examine the associations among the LCQ, HARQ, and CQLQ. Patient demographics and patient-reported CC features were compared between males and females, and among ethnic groups using Robust Poisson regression models.

RESULTS

The survey was completed by 565 patients who were 64.8 ± 12.6 years, 75.8% female, and 60.4% white. CC duration was 8.6 ± 10.5 years with an average weekly severity of 5.3 ± 2.3 (maximum 10). The LCQ score was 11.3 ± 3.9 (maximum 21). The HARQ score was 33.3 ± 13.6 (normal ≤13). The CQLQ score was 56.9 ± 17.5 (maximum 112, worse with higher scores). The Spearman rank correlations were high between the LCQ and HARQ (-0.65), the LCQ and CQLQ (-0.80), and the HARQ and CQLQ (0.69). Patients with CC-associated respiratory and gastrointestinal comorbidities generally showed similar results regarding the above questionnaires. Treatment responses were suboptimal. Women compared with men and non-whites compared with whites reported significantly worse cough severity and poorer LCQ, HARQ, and CQLQ scores.

CONCLUSIONS

CC is self-reported as a burdensome condition, particularly in women and non-white minorities, which markedly affects daily living with inadequate response to treatments.

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

Chronic cough is a common complaint in the general population but there are no precise data on the incidence of, and prospectively examined risk factors for chronic cough in a population-based setting. Therefore, we investigated the period prevalence, incidence and risk factors for chronic cough in adult subjects. In a prospective population-based cohort study among subjects aged ≥45 years, data on chronic cough were collected on two separate occasions using a standardised questionnaire. Chronic cough was defined as daily coughing for at least 3 months duration during the preceding 2 years. Potential risk factors were gathered by interview, physical examination and several investigations. Of the 9824 participants in this study, 1073 (10.9%) subjects had chronic cough at baseline. The prevalence of chronic cough increased with age and peaked in the eighth decade. In subjects aged <70 years, chronic cough was more common in women. During an average follow-up of 6 years, 439 incident cases of chronic cough occurred with an overall incidence rate of 11.6 per 1000 person-years (95% CI 10.6-12.8). In current smokers, the incidence of chronic cough was higher in men. In the multivariable analysis, current smoking, gastro-oesophageal reflux disease (GORD), asthma and COPD were identified as risk factors for chronic cough. Chronic cough is common among adults and highly prevalent in the older population. Current smoking, GORD, asthma and COPD are independent risk factors for chronic cough. Individuals at risk of developing chronic cough may benefit from smoking cessation and control of the underlying disease.

Burden of Specialist-Diagnosed Chronic Cough in Adults

BACKGROUND

The burden of chronic cough (CC) in patients seeking specialist care is infrequently researched.

OBJECTIVE

To describe patient characteristics and disease burden associated with specialist-diagnosed CC.

METHODS

Using administrative pharmacy and medical data, we identified patients aged 18 to 85 years with CC diagnosed by pulmonologists, allergists, otolaryngologists, or gastroenterologists. Patients were stratified into 4 subgroups on the basis of the presence or absence of common respiratory diseases or gastroesophageal reflux disease (GERD). Clinical features and health care resource utilization (HCRU) in the baseline and outcome years were compared between the CC subgroups. The baseline factors associated with persistence of CC and a comparison of the CC cohort to a matched noncough cohort were also determined.

RESULTS

The 11,290 patients with specialist-diagnosed CC were aged about 61 years and 66.7% were females. The CC cohort experienced frequent GERD (44.1%), asthma (31.2%), obesity (24.3%), upper airway cough syndrome (20.4%), common cough complications (19.4%), and hospitalizations (9.8%). The patients with CC with both respiratory disease and GERD exhibited at baseline and follow-up the most common cough comorbidities, higher HCRU, specialist care, and dispensed respiratory and nonrespiratory medications including proton pump inhibitors, antitussives, psychotherapeutics, oral corticosteroids, and antibiotics compared with the other subgroups. A 40.6% persistence of CC occurred similarly between CC subgroups. In addition, patients with CC in the matched analysis experienced significantly more comorbidities, laboratory evaluations, HCRU, and antitussives than patients without cough.

CONCLUSIONS

Specialist-diagnosed CC was associated with considerable disease burden, particularly among those with both respiratory disease and GERD. In addition, CC burden was more pronounced than in matched patients without cough.

Clinical Characteristics of Chronic Cough in Korea

BACKGROUND

Chronic cough is defined as a cough lasting more than 8 weeks and socio-economic burden of chronic cough is enormous. The characteristics of chronic cough in Korea are not well understood. The Korean Academy of Tuberculosis and Respiratory Diseases (KATRD) published guidelines on cough management in 2014. The current study evaluated the clinical characteristics of chronic cough in Korea and the efficacy of the KATRD guidelines.

METHODS

This was a multi-center, retrospective observational study conducted in Korea. The participants were over 18 years of age. They had coughs lasting more than 8 weeks. Subjects with current pulmonary diseases, smokers, ex-smokers with more than 10 pack-years or who quit within the past 1 year, pregnant women, and users of cough-inducing medications were excluded. Evaluation and management of cough followed the KATRD cough-management guidelines.

RESULTS

Participants with chronic cough in Korea showed age in the late forties and cough duration of more than 1 year. Upper airway cough syndrome was the most common cause of cough, followed by cough-variant asthma (CVA). Gastro-esophageal reflux diseases and eosinophilic bronchitis were less frequently observed. Following the KATRD cough-management guidelines, 91.2% of the subjects improved after 4 weeks of treatment. Responders were younger, had a longer duration of cough, and an initial impression of CVA. In univariate and multivariate analyses, an initial impression of CVA was the only factor related to better treatment response.

CONCLUSION

The causes of chronic cough in Korea differed from those reported in other countries. The current Korean guidelines proved efficient for treating Korean patients with chronic cough.

Prevalence and Characteristics of Chronic Cough in Adults Identified by Administrative Data

CONTEXT

International Classification of Diseases-9/10 codes for chronic cough (CC) do not exist, limiting investigation.

OBJECTIVE

To develop a computerized algorithm to determine CC prevalence and its characteristics.

DESIGN

This observational study using administrative data identified hierarchically patients aged 18 to 85 years with CC from 2013 to 2016. First, a specialist-diagnosed CC group was identified using an internal CC encounter code during an outpatient visit to a pulmonologist, allergist, otolaryngologist, or gastroenterologist. Subsequently, an event-diagnosed CC group was identified based on clinical notes through natural language processing, ICD-9/ICD-10 cough codes, and dispensed antitussives.

MAIN OUTCOME MEASURES

Prevalence of CC and comparison of clinical characteristics between specialist-diagnosed and event-diagnosed CC subgroups.

RESULTS

A total of 50,163 patients with CC of more than 8 weeks were identified. Of these, 11,290 (22.5%) were specialist diagnosed, and 38,873 (77.5%) were event diagnosed. The CC cohort was 57.4 ± 16.5 years of age; 67.6% were female. The overall prevalence was 1.04% (95% confidence interval = 1.03-1.06) in 2016. Prevalence in 2016 was higher in female patients (1.21%) than in male patients (0.81%), higher in patients aged 65 to 85 years (2.2%) than in patients aged 18 to 44 years (0.43%), and higher in Blacks (1.38%) than in Whites (1.21%). Compared with patients with event-diagnosed CC, patients with specialist-diagnosed CC exhibited significantly higher frequencies of laboratory tests and respiratory and nonrespiratory comorbidities and dispensed medication and lower frequency of pneumonia, all-cause and respiratory-cause emergency department visits and hospitalizations, and dispensed antitussives.

CONCLUSIONS

We identified a CC cohort using electronic data in a managed care organization. Prevalences varied by sex, age, and ethnicity. Clinical characteristics varied between specialist-diagnosed and event-diagnosed CC.

Bronchiectasis and cough: An old relationship in need of renewed attention

Bronchiectasis is an increasingly recognised respiratory condition with limited therapeutic options and a complex spectrum of clinical manifestations that invariably includes chronic cough. As the primary presentation of bronchiectasis in most cases, chronic cough and its mechanistic underpinnings are of central importance but remain poorly understood in this setting. Bronchiectasis is also increasingly identified as an underlying cause of chronic cough highlighting the interrelationship between the two conditions that share overlapping clinical features. Several therapeutic approaches have illustrated positive effects on bronchiectasis-associated cough, however, more focused treatment of heterogeneous cough subtypes may yield better outcomes for patients. A current challenge is the identification of bronchiectasis and cough endophenotypes that may allow improved patient stratification and more targeted therapeutic matching of the right treatment to the right patient. Here we discuss the complex disease phenotypes of bronchiectasis and their interrelationship with cough while considering current and emerging treatment options. We discuss some key cough promoters in bronchiectasis including infection, allergy and immune dysfunction.

Chronic cough as a novel phenotype of chronic obstructive pulmonary disease

Background and purpose

Chronic cough can be a dominant symptom of chronic obstructive pulmonary disease (COPD), although its clinical impact remains unclear. The aim of our study was to identify phenotypic differences according to the presence of chronic cough or sputum and evaluate the impact of chronic cough on the risk of acute exacerbation of COPD (AECOPD).

Methods

In a nationwide COPD cohort including 1,613 COPD patients, patients with chronic cough only, those with sputum only, those with chronic bronchitis (CB), and those without cough and sputum were compared with regard to dyspnea, lung function, quality of life (QoL), and risk of AECOPD.

Results

The rates of chronic cough, chronic sputum, and both were 23.4%, 32.4%, and 18.2%, respectively. Compared with patients without chronic cough, those with chronic cough exhibited a lower forced expiratory volume in 1 second (% predicted) and diffusing capacity of the lungs for carbon monoxide (% predicted), more frequent AECOPD, more severe dyspnea, and worse QoL. Pulmonary function, dyspnea severity, and QoL worsened in the following order: without cough or sputum, with sputum only, with cough only, and with CB. Multivariate analyses revealed chronic cough as an independent risk factor for a lower lung function, more severe dyspnea, and a poor QoL. Moreover, the risk of future AECOPD was significantly associated with chronic cough (odds ratio 1.56, 95% CI 1.08-2.24), but not with chronic sputum.

Conclusion

Our results suggest that chronic cough should be considered as an important phenotype during the determination of high-risk groups of COPD patients.