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

Current opinion in refractory and/or unexplained chronic cough

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Multidisciplinary team discussion based on etiological treatment improves refractory chronic cough outcomes

BACKGROUND

Refractory chronic cough (RCC) causes significant impairments in the life quality of patients. Further research into the identification of etiologies and development of the treatment schedules for RCC is needed.

PATIENTS AND METHODS

We established an multidisciplinary team (MDT) clinic, by integrating respiratory medicine, otorhinolaryngology, and gastroenterology departments, to investigate cough etiologies and the effectiveness of treatment. The therapeutic effect was assessed quantitatively using the Cough Visual Analog Scales (VAS), Leicester Cough Questionnaire (LCQ), and Reflux Symptoms Index (RSI) scores.

RESULTS

In total, 213 patients attending the MDT outpatient clinic were examined, and 115 patients with RCC were included for analysis. The RCC diagnosis rate among the outpatient was 88.7%. Common causes of RCC included gastroesophageal reflux cough (63.5%), upper airway cough syndrome (UACS) (43.5%), and cough variant asthma (CVA) (14.8%). After an average treatment period of 2.17 ± 1.06 weeks (wk), 73.9% of the patients had partial cough remission, and 6.1% had complete cough remission. The cough VAS score before and after treatment was 6.11 ± 2.02 vs. 3.66 ± 2.22 (P < 0.05), respectively; LCQ total score before and after treatment was 10.24 ± 3.11 vs. 13.16 ± 3.59 (P < 0.05), respectively; and RSI score before and after treatment was 15.82 ± 7.01 vs. 10.71 ± 6.64 (P < 0.05), respectively.

CONCLUSION

The etiologies of most patients with RCC could be identified in the MDT clinic, and the cough-related symptoms of a significant number of patients with RCC improved in a short period.

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.

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.

Relevant factors associated with the development of chronic cough after recovery from COVID-19

BACKGROUND

Cough is one of the symptoms of the post-COVID-19 condition. However, the factors associated with its development remain unclear. We evaluated the factors associated with chronic cough in the post-COVID-19 condition.

METHODS

In this survey, 170 individuals who previously had COVID-19 and were admitted to Aichi Hospital between October 2020 and October 2021 were included. Using self-developed questionnaires and visual analog scales, 19 symptoms, including cough, were assessed. Cough-specific quality of life (QoL), reflux-related symptoms, and abnormal laryngeal sensations were also evaluated. The patients' clinical characteristics and indices, including cough-specific QoL, at admission were extracted from their medical records. Multivariate regression analyses were conducted to determine the factors associated with cough-related outcomes, such as prevalence, QoL, and severity, in the post-COVID-19 condition.

RESULTS

The median length (range) of the survey after recovery from COVID-19 was 158 (95-467) days. Cough was prevalent (n = 41, 24 %) and often accompanied by other symptoms, including gastrointestinal symptoms. Cough-specific QoL after recovery was correlated with reflux-related symptoms and abnormal laryngeal sensations. Multivariate analyses revealed that gastrointestinal symptoms, sputum, and chronic cough before contracting COVID-19 are significant predictors of cough-related outcomes in the post-COVID-19 condition. Meanwhile, other indices including cough-specific QoL on the acute phase were not reliable predictors in the post-COVID-19 condition.

CONCLUSIONS

Cough during the post-COVID-19 condition had a negative impact on daily life activities. Gastrointestinal symptoms could play a significant role in the pathophysiology of cough in such a condition.

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.

Association of novel adult cough subclasses with clinical characteristics and lung function across six decades of life in a prospective, community-based cohort in Australia: an analysis of the Tasmanian Longitudinal Health Study (TAHS)

BACKGROUND

Cough is a common yet heterogeneous condition. Little is known about the characteristics and course of cough in general populations. We aimed to investigate cough subclasses, their characteristics from childhood across six decades of life, and potential treatable traits in a community-based cohort.

METHODS

For our analysis of the Tasmanian Longitudinal Health Study (TAHS), a prospective, community-based cohort study that began on Feb 23, 1968, and has so far followed up participants in Tasmania, Australia, at intervals of 10 years from a mean age of 7 years to a mean age of 53 years, we used data collected as part of the TAHS to distinguish cough subclasses among current coughers at age 53 years. For this analysis, participants who answered Yes to at least one cough-related question via self-report questionnaire were defined as current coughers and included in a latent class analysis of cough symptoms; participants who answered No to all nine cough-related questions were defined as non-coughers and excluded from this analysis. Two groups of longitudinal features were assessed from age 7 years to age 53 years: previously established longitudinal trajectories of FEV1, forced vital capacity [FVC], FEV1/FVC ratio, asthma, and allergies-identified via group-based trajectory analysis or latent class analysis-and symptoms at different timepoints, including asthma, current productive cough, ever chronic productive cough, current smoking, and second-hand smoking.

FINDINGS

Of 8583 participants included at baseline in the TAHS, 6128 (71·4%) were traced and invited to participate in a follow-up between Sept 3, 2012, and Nov 8, 2016; 3609 (58·9%) of these 6128 returned the cough questionnaire. The mean age of participants in this analysis was 53 years (SD 1·0). 2213 (61·3%) of 3609 participants were defined as current coughers and 1396 (38·7%) were categorised as non-coughers and excluded from the latent class analysis. 1148 (51·9%) of 2213 participants in this analysis were female and 1065 (48·1%) were male. Six distinct cough subclasses were identified: 206 (9·3%) of 2213 participants had minimal cough, 1189 (53·7%) had cough with colds only, 305 (13·8%) had cough with allergies, 213 (9·6%) had intermittent productive cough, 147 (6·6%) had chronic dry cough, and 153 (6·9%) had chronic productive cough. Compared with people with minimal cough, and in contrast to other cough subclasses, people in the chronic productive cough and intermittent productive cough subclasses had worse lung function trajectories (FEV1 persistent low trajectory 2·9%, 6·4%, and 16·1%; p=0·0011, p<0·0001; FEV1/FVC early low-rapid decline trajectory 2·9%, 12·1%, and 13·0%; p=0·012, p=0·0007) and a higher prevalence of cough (age 53 years 0·0%, 32·4% [26·1-38·7], and 50·3% [42·5-58·2]) and asthma (age 53 years 6·3% [3·7-10·6], 26·9% [21·3-33·3], and 41·7% [24·1-49·7]) from age 7 years to age 53 years.

INTERPRETATION

We identified potential treatable traits for six cough subclasses (eg, asthma, allergies, and active and passive smoking for productive cough). The required management of productive cough in primary care (eg, routine spirometry) might differ from that of dry cough if our findings are supported by other studies. Future population-based studies could apply our framework to address the heterogeneity and complexity of cough in the community.

FUNDING

The National Health and Medical Research Council of Australia, The University of Melbourne, Clifford Craig Medical Research Trust of Tasmania, Victorian Asthma Foundation, Queensland Asthma Foundation, Tasmanian Asthma Foundation, The Royal Hobart Hospital Research Foundation, the Helen MacPherson Smith Trust, GlaxoSmithKline, and the China Scholarship Council.

Gender Differences in Antitussive Prescriptions for Chronic Cough in Korea

Background: We investigated the differences in the characteristics and prognoses between the sexes of patients with chronic cough who were prescribed antitussive agents, using a Korean population-based database. Methods: Claims data from South Korea's Health Insurance Review and Assessment (HIRA) service were analyzed. This retrospective observational cohort study considered chronic cough patients aged 18 years and older who were consistently prescribed antitussive agents for more than 2 months between 1 January 2017 and 30 June 2019. Results: Among the 207,989 patients treated for chronic cough, the prevalence of unexplained cough was higher in women (men: 6.2% vs. women: 9.7%) and the prevalence of persistent cough was higher in men (men: 16.8% vs. women: 14.3%). The gap in the proportion of COPD, lung cancer, ILD, GERD, and TB between women and men were largest around the age range of 60-70 years. With the exception of those in their 60s and 70s, women were more likely to have chronic cough and persistent cough than men. Women were more likely to discontinue medication after treatment completion than men. Only 53.9% of patients discontinued cough medication for more than 6 months after treatment completion. Within 12 and 18 months, respectively, 8.9% and 11.9% of them revisited the hospital for chronic cough. Via Cox regression analysis, an age in the 60s or 70s and explained cough were independently associated with a higher risk of revisit for treatment. Conclusions: Among patients treated for chronic cough, there were distinct differences in cough characteristics and prescription status between men and women. Our data highlight the need for a new personalized treatment approach to chronic cough, taking into account the gender, age, and underlying diseases of patients. Further research is needed to determine whether appropriate underlying disease control and gender-specific treatment are effective for managing chronic cough.

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.

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.

Incidence and Prevalence of Cough in a Rural Health System: A 20‐Year Study

OBJECTIVE

Understanding the cough population is critical to addressing clinical needs and gaps in best practice. We sought to characterize and stratify cough patients with the hypothesis that there are opportunities to improve access to care in our health system and characterize the population.

METHODS

Following institutional review board exempt status, a retrospective electronic record review was performed on all patients coded with ICD-9 786.2 or ICD-10 is R05 from January 1, 2001 through December 31, 2020 at our health system. Inclusion criteria were one or more visits for cough. The subgroup with more than one visit in each of 2 years was classified as multiple encounters. Patients were characterized by sex, age at first cough encounter, number of cough encounters, smoking status, and insurance status. Results were stratified by year, calculating frequencies, and percentages.

RESULTS

There were 302,284 unique patients diagnosed with cough, among 1,764,387 patients seen in our health system, representing an average incidence of 3.0% (2.7%-3.7%) and prevalence of 4.9% (3.1%-5.6%). New single encounter cough patients totaled 179,963, and new multiple encounter cough patients totaled 122,321. Of the 39,828,073 total encounters, there were 469,802 for new or existing cough (1.17%-1.73% annually). The age at initial presentation demonstrated 36.5% seen <10 years old, with an even distribution over the remaining decades of life. The majority were seen for cough once, but 23.8% of group two patients had two or more visits for cough in a year.

CONCLUSION

We demonstrate a lower-than-expected incidence and prevalence of cough in our health population, suggesting challenges with access to care when compared to 10% prevalence and 3% of encounters previously documented in the literature. The study also provides a platform to explore the importance of pediatric cough, as well as population health and the longitudinal journey of cough patients in underserved areas.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:1191-1196, 2023.

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.