Classification of Cough as a Symptom in Adults and Management Algorithms: CHEST Guideline and Expert Panel Report

Effect of the treatment of iron deficiency anemia on chronic drug-resistant cough: a rare case report

BACKGROUND

A persistent difficult-to-treat cough can be exhausting. Iron is an essential element that plays an important role in regulating the production of pro-inflammatory cytokines, and its deficiency may potentiate airway inflammation and dysfunction. There is a paucity of data regarding a link between iron deficiency (ID) and idiopathic cough.

OBJECTIVES

In this study, a case of persistent non-productive cough, which was unresponsive to targeted treatment approaches but responsive to iron therapy, is reported.

METHODS

A 53-year-old woman came to a medical clinic with complaints of a chronic and progressive non-productive cough. She underwent a complete clinical and paraclinical evaluation.

RESULTS

Her vital signs were stable and no abnormalities were found on the physical examination. The results of the spirometry and chest radiography were unremarkable. The laboratory test indicated hypochromic microcytic anemia, with a hemoglobin value of 9.6 g/dL. Her cough was resolved after treatment of iron-deficiency anemia with an oral nutraceutical capsule containing 28 mg of elemental iron (as ferrous bis-glycinate) plus folic acid, vitamin B12, and vitamin C, once daily for six months.

CONCLUSION

In the case of unexplained chronic cough, resistant to targeted therapies, investigation and treatment of ID may contribute to the resolution of cough.

Efficacy and safety of gefapixant in women with chronic cough and cough-induced stress urinary incontinence: a phase 3b, randomised, multicentre, double-blind, placebo-controlled trial

BACKGROUND

Approximately two-thirds of women with chronic cough have cough-induced stress urinary incontinence (CSUI). We aimed to evaluate the efficacy and safety of gefapixant in reducing CSUI episodes in women with refractory or unexplained chronic cough.

METHODS

This phase 3b, double-blind, randomised, placebo-controlled trial done at 90 sites in 12 countries enrolled women aged 18 years or older who had chronic cough for at least 1 year, a diagnosis of refractory or unexplained chronic cough, a cough severity visual analogue scale score of 40 mm or more (100 mm maximum), and CSUI for 3 months or more. Participants were randomised 1:1 to oral gefapixant or placebo for 12 weeks. The primary outcome was percentage change from baseline in daily CSUI episodes (7-day average) at week 12. This study is registered with ClinicalTrials.gov (NCT04193176).

FINDINGS

From May 10, 2020, to Sept 2, 2022, 375 participants were randomised to and treated with gefapixant 45 mg twice daily (n=185) or placebo (n=190). Mean age was 56·4 years (SD 11·4), with mean chronic cough duration of 5·2 years (SD 6·6) and SUI duration of 4·0 years (SD 5·9). Least-squares mean percentage change from baseline in daily CSUI episodes was -52·8% (95% CI -58·4 to -47·1%) for gefapixant and -41·1% (-46·7 to -35·4%) for placebo (estimated treatment difference: -11·7% [95% CI -19·7 to -3·7]; p=0·004). 129 (70%) of 185 participants who received gefapixant and 71 (37%) of 190 participants who received placebo had at least one adverse event. Safety and tolerability were consistent with previous trials of gefapixant; the most frequent adverse events were taste related.

INTERPRETATION

Gefapixant 45 mg twice daily is the first treatment to show efficacy versus placebo in reducing CSUI episodes in participants with refractory or unexplained chronic cough.

FUNDING

Merck Sharp & Dohme, a subsidiary of Merck & Co.

The discovery and development of gefapixant as a novel antitussive therapy

INTRODUCTION

Gefapixant, a P2X 3 receptor antagonist, shows considerable potential in managing refractory or unexplained chronic cough. Clinical trials have consistently demonstrated its efficacy in significantly reducing cough frequency and alleviating associated symptoms. However, its adverse effect profile, particularly taste disturbances such as dysgeusia and hypogeusia, the incidence of which is dose-dependent, poses a significant challenge to patient compliance and overall treatment satisfaction.

AREAS COVERED

The authors review the mechanism of action of gefapixant, the dose-dependent nature of its adverse effects and the findings from various clinical trials, including Phase 1, Phase 2, and Phase 3 studies. The authors also cover its regulatory status, post-marketing data, and its main competitors.

EXPERT OPINION

Gefapixant represents a significant advancement in treating chronic cough. However, balancing efficacy and tolerability is crucial. Lower effective doses and potential combination therapies may mitigate taste disturbances. Patient education and close monitoring during treatment are also important for optimal outcomes. Further research is needed to refine dosing strategies to minimize side effects while maintaining therapeutic efficacy. This research and personalized treatment approaches are key to optimizing gefapixant therapy, ensuring improved management of chronic cough while reducing adverse effects. However, pharmaceutical trials and proposals must be adapted to align with each regulatory body's specific requirements and concerns.

Development of a rapid method for the simultaneous determination of aminophylline, doxofylline, bromhexine, and ambroxol by HPLC

Introduction: Antitussive and expectorant drugs such as aminophylline (APL), doxofylline (DXL), bromhexine hydrochloride (BXH), and ambroxol hydrochloride (AXH), either individually or in combination, are widely used in the prevention and treatment of respiratory diseases. The study aimed to establish a high-performance liquid chromatography (HPLC) method for the simultaneous determination of these four drugs and to investigate their stability in 0.9% sodium chloride injection or 5% glucose injection over 48 hours. Methods: An InertSustain C18 column (150 mm × 4.6 mm, 5 μm) was used. The mobile phase consisted of acetonitrile and 50 mmol·L-1 potassium dihydrogen phosphate solution (pH 4.0) with gradient elution. The flow rate was 0.8 mL·min-1, and the column temperature was maintained at 30°C. The stability of APL, DXL, BXH, and AXH in 0.9% sodium chloride and 5% glucose injections over 48 h was determined using HPLC. Results: APL, DXL, BXH, and AXH showed good linearity within the ranges of 0.01 to 0.20, 0.003-0.06, 0.015-0.30, and 0.016-0.16 mg·mL-1, respectively (r > 0.999). The intraday and interday relative standard deviations were <2%, with recovery rates between 98.4% and 102.2%. The four drugs remained colorless and clear in infusion mixtures. The pH value fluctuated within ±0.3 over 48 hours, and the relative percentage content of the drugs ranged from 95.0% to 105.0%. Conclusion: The established HPLC method is simple, reliable, and stable, allowing for the simultaneous determination of the four antitussive and expectorant drugs. APL, DXL, BXH, and AXH were stable within 48 hours when mixed with 0.9% sodium chloride and 5% glucose injections.

Prescription patterns and symptom relief of antitussives and expectorants in patients with cough: a nationwide study in Korea

Background

Limited data are available on the prescription patterns and efficacy of antitussives and expectorants for patients with acute and chronic cough. This study examined the use and efficacy of these medications in a nationally representative sample of Korean patients.

Methods

We examined 4,206,016 individuals from the National Health Insurance Service (NHIS)-National Health Information Database (NHID) between 2015 and 2017. Among them, a sample of 10% (n=420,602) was retrieved for the diagnosis of respiratory diseases using the International Classification of Diseases, 10th edition (ICD-10; J00-J99), or the prescription of antitussives and expectorants for cough (ICD-10; R05). The acute cough group included those who were prescribed medications within 4 weeks of initial diagnosis (prescription within 14 days), whereas the chronic cough group included patients who were prescribed medications within 16 weeks of initial diagnosis (prescription within 56 days). If the prescription was discontinued or not changed to an alternative drug after the initial prescription, these cases were considered to have achieved symptom relief.

Results

This study included 288,460 patients (971,065 cases) with acute cough and 5,888 patients (15,399 cases) with chronic cough. 'Expectorants, excluding combinations with cough suppressants' had the highest prescription rates in both groups (acute cough, 63.8%; chronic cough, 61.7%), and showed the highest symptom relief regardless of the number of medications prescribed (acute cough, 84.3%; chronic cough, 70.4%).

Conclusions

'Expectorants, excluding combinations with cough suppressants' were the most prescribed and effective medications for relieving cough symptoms in Korea patients. Further studies are needed to determine the optimal duration for using antitussives and expectorants in cough management.

Are Otolaryngologists Seeing More Cough? Longitudinal Trends and Patterns

OBJECTIVE

Otolaryngologists play an increasing role in managing cough, but little data exists examining the demographics of this patient population and the referral patterns that influence their access to care. This study sought to elucidate these factors using a longitudinal, nationwide database to minimize sampling bias and identify trends representative of the national population.

STUDY DESIGN

Nationally representative survey.

SETTING

National Ambulatory Medical Care Survey (NAMCS).

METHODS

Visits with a diagnosis and chief complaint of cough between 2005 and 2019 in NAMCS were examined. Univariable and multivariable analyses were performed to compare patient demographics between visits to surgical specialists, medical specialists, and primary care physicians.

RESULTS

Otolaryngologists made up more than 84% of surgical specialist visits. There was a 0.52% [0.20%-0.84%] increase per year in the proportion of visits attributed to surgical specialists. Based on a sensitivity analysis of the multivariable model, Hispanic patients (adjusted odds ratio, aOR: 0.88 [0.78-0.99] vs White) and patients living outside of metropolitan areas (aOR: 0.77 [0.61-0.99] vs living within) were less likely to see surgical specialists than primary care doctors for their cough. Patients who were referred (aOR: 1.47 [1.28-1.72] vs not referred) and with chronic cough (aOR: 1.47 [1.23-1.75] vs acute/subacute) were more likely to see a surgical specialist.

CONCLUSION

Otolaryngologists are increasingly called upon to evaluate and consider treatment for cough. Identifying patient groups with limited access underscores the need for enhanced education about otolaryngologists' roles and integrated care approaches to improve access to specialized cough treatment.

LEVEL OF EVIDENCE

Level 4.

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.

Prevalence and clinical relevance of comorbid pertussis infection in adult patients with asthma: A prospective, cross-sectional study

BACKGROUND

Viral or atypical bacterial respiratory infections are involved in the new development and the pathogenesis of asthma. Though an association between pertussis and asthma has been expected, few studies have reported it consistently. We assessed the prevalence and clinical relevance of pertussis infection in adult patients with asthma.

METHODS

In this prospective, cross-sectional study, newly referred, adult patients with asthma (n = 107) and with non-asthmatic subacute/chronic cough (n = 31) were enrolled. The prevalence of pertussis in patients with asthma and in those with non-asthmatic subacute/chronic cough was assessed. Next, the prevalence of newly diagnosed asthma was compared between asthmatic patients with and without pertussis. Finally, demographic characteristics of patients, blood test results, pulmonary function test results, and questionnaire scores were compared between the two patient groups.

RESULTS

The prevalence of pertussis infection was significantly higher in patients with asthma than in those with non-asthmatic subacute/chronic cough (36% vs 10%; P = 0.004). The prevalence of newly diagnosed asthma was significantly higher in asthmatic patients with pertussis than in those without (74.4% vs 50.0%; P = 0.014). The physical, psychological, and total scores of the Leicester Cough Questionnaire were significantly lower in asthmatic patients with pertussis than in those without (all P < 0.05). The acid-reflux, dyspeptic, and total scores of the Frequency Scale for Symptoms of Gastroesophageal Reflux Disease (GERD) (FSSG) were significantly higher in asthmatic patients with pertussis than in those without (all P ≤ 0.05). The FSSG acid-reflux score was negatively correlated with the cough-specific quality of life (QOL) score only in asthmatic patients with pertussis (rho = -0.68, P = 0.01).

CONCLUSIONS

The prevalence of pertussis infection was significantly higher in adult patients with asthma than in those with non-asthmatic subacute/chronic cough. In patients with asthma, comorbid pertussis infection may play a role in newly diagnosed asthma and may contribute to impaired cough-specific QOL partly due to worsening acid-reflux symptoms of GERD.

Prevalence of refractory and unexplained chronic cough in adults treated in cough centre

Background

Refractory chronic cough and unexplained chronic cough pose significant clinical challenges, impairing patients' quality of life. However, a precise definition of refractory chronic cough remains elusive. This study aimed to assess the prevalence of refractory and unexplained chronic cough among patients referred to our cough centre and to analyse the prevalence of refractory chronic cough relative to its definition.

Methods

This prospective cohort study included all patients who were diagnosed at a cough clinic between 2018 and 2022. The response to therapy was measured based on reduction in cough severity (via a visual analogue scale) and improvement in cough-related quality of life (via the Leicester Cough Questionnaire). Refractory chronic cough was defined as persistent cough severity, with no or minimal improvement (change in visual analogue scale <30 mm) after two or more treatment attempts and cough severity ≥40 out of 100 mm on the visual analogue scale.

Results

Of 201 patients treated for chronic cough, only three (1.5%) were diagnosed with unexplained chronic cough. Among 166 patients monitored for therapy response, 71 (42.8%) experienced a cough severity reduction of ≥30 mm on the visual analogue scale, while 100 (60.2%) showed an improvement of ≥1.5 points on the Leicester Cough Questionnaire. Based on the basic refractory chronic cough definition, 51 of 166 patients (30.7%) were diagnosed with refractory chronic cough. If applying stricter criteria (persistent severe cough (≥40 mm on the visual analogue scale), insufficient therapy response (<30 mm reduction on the visual analogue scale) and <1.5-point improvement on the Leicester Cough Questionnaire), 45 of 166 patients (27.1%) would be diagnosed with refractory chronic cough.

Conclusions

Refractory chronic cough is common in patients referred to cough clinics. The prevalence of refractory chronic cough differs slightly depending on the diagnostic criteria. Therefore, the definition of refractory chronic cough used in routine practice needs to be clarified.

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).

Gastroesophageal reflux disease in chronic obstructive pulmonary disease

Gastroesophageal reflux disease (GERD) is one of the most common comorbidities of chronic obstructive pulmonary disease (COPD). Decreased lower and upper esophageal sphincter pressures, esophageal dysmotility, high transdiaphragmatic pressure, and decreased saliva secretion have been implicated as mechanisms leading to the development of GERD in COPD. Clinically, comorbid GERD in COPD is reportedly associated with worse symptoms, quality of life, and lung function, as well as a high risk of exacerbations. Aspiration of regurgitation and the cholinergic-mediated esophagobronchial reflex play a significant role in the pathophysiology. Abnormal swallowing reflexes and discoordination of swallowing can worsen aspiration. The diagnosis of GERD is not based on a single criterion; however, various approaches, including questionnaires and endoscopic evaluations, can be widely applied in clinical settings. Due to the increased risk of esophageal and gastric cancers in patients with COPD, the threshold for endoscopic examination should be low. Acid inhibitory agents, such as proton pump inhibitors and histamine H2 receptor antagonists, and prokinetic agents, including mosapride and itopride, are clinically used to treat GERD. Endoscopic fundoplication can be performed in patients with GERD refractory to medical treatment. There is still insufficient evidence, but an increasing number of studies have suggested the clinical efficacy of treatment in patients with COPD and GERD. As GERD is an evaluative and treatable common disease, and access to evaluation and treatment is relatively easy, clinicians should provide adequate care for GERD in the management of COPD.

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.

Medication adherence and associated factors among chronic heart failure patients on follow-up in north Shewa public hospitals, Oromia region, Ethiopia

BACKGROUND

Chronic heart failure affects approximately 26 million people globally. World Health Organization data show that only approximately half of chronically ill patients in developed countries adhere to recommended medication, with even lower rates in developing countries. Medication adherence is critical for managing chronic heart failure symptoms, delaying disease progression, and preventing hospitalizations. However, poor adherence increases rehospitalization, morbidity, mortality, and healthcare costs.

OBJECTIVE

To assess medication adherence and associated factors among chronic heart failure patients on follow-up at North Shewa Public Hospitals, Oromia Region, Ethiopia, in 2023.

METHODS

This institutional-based cross-sectional study was conducted from March 1 to April 30, 2023, G.C. A total of 603 individuals were selected consecutively among those who underwent chronic OPD after being proportionally allocated to five hospitals in the zone. The data were collected using an interviewer-administered questionnaire and a medical chart review. The data were entered into Epi-data version 3.1 and then exported to SPSS version 26 for analysis. The multivariable logistic regression model included variables with a P value < 0.25 in the bivariate analysis. The degree of association was expressed using an adjusted odds ratio (AOR) with a 95% confidence interval (CI) at a P value < 0.05.

RESULTS

Among the 603 patients, 56% had optimal medication adherence, with a 95% CI of 52.1 to 60. Being able to read and write (AOR: 2.20; 95% CI: 1.34, 3.61), having a secondary education (AOR: 1.97; 95% CI: 1.06, 3.67), having community-based health insurance (AOR: 1.82; 95% CI: 1.22, 2.71), not having comorbidities (AOR: 1.82; 95% CI: 1.18, 2.52), taking several drugs < 2 (AOR: 2.11; 95% CI: 1.20, 2.45), not adding salt when cooking (AOR: 1.72; 95% CI: 1.20, 2.45), and asking a doctor or nurse without fear (AOR: 1.87; 95% CI: 1.03, 3.40) were factors associated with medication adherence among CHF patients.

CONCLUSION

This study revealed that 56% of chronic heart failure patients had optimal medication adherence. Factors associated with higher adherence included higher education, community health insurance, lack of comorbidities, fewer medications, avoiding added salt, and comfortable communication with providers. Health professionals should provide education to strengthen medication adherence.

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.

Awareness and practices of Speech Language Pathologists (SLPs) working with chronic cough in India: a call for action

OBJECTIVE

A cough persisting beyond eight weeks is referred as chronic cough (CC) and is a common symptom of many respiratory conditions and non-respiratory conditions. The role of a speech language pathologist (SLP) in CC is emerging and this study aimed to profile the awareness and practice patterns of SLPs practicing in India.

STUDY DESIGN

Cross-sectional study.

METHOD

An online survey was used to profile the assessment, treatment and counselling practices in CC among SLPs working in India. It sought to identify the awareness levels among SLPs regarding their role and availability of behavioural interventions for CC. Only SLPs who dealt with CC could complete the entire survey while other SLPs, filled regarding awareness and availability of behavioural interventions.

RESULTS

127 eligible responses obtained from SLPs working across clinical settings in India were analysed. 75.59% (n=96) of them had not seen patients with CC in their career. 47.24% (n=60) of them were aware that behavioural interventions were available for CC. Thirty-one SLPs completed the entire survey and their practice patterns indicated that few clinicians used cough-specific protocols while largely relying on voice and swallowing related assessment and treatment for CC.

CONCLUSION

This survey the lack of awareness of SLPs' role in CC and that their practices are dominated by existing procedures for voice and swallowing disorders. Increasing the awareness of SLP's role in CC may increase the caseload of patients referred and expand the SLP's scope of practice. Development of guidelines in CC practice and inclusion in coursework/curriculum are future considerations.

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.

The status and influencing factors of COVID-19 vaccination in patients with COPD

In this study, we investigated the status and influencing factors of coronavirus disease 2019 (COVID-19) vaccination in patients with chronic obstructive pulmonary disease (COPD). A questionnaire on COVID-19 vaccination in patients with COPD was developed. The clinical characteristics, COVID-19 vaccination status, other relevant vaccinations, and vaccination status of the patients with COPD were collected anonymously. Logistic regression analysis was used to analyze the factors influencing COVID-19 vaccination in patients with COPD. There were 1898 returned questionnaires, of which 1874 were valid. The proportion of patients who completed the COVID-19 vaccination program was 78.60%. Factors influencing the COVID-19 vaccination rate were: the age of individuals who were 75-85 years old and > 85 years old, acute exacerbation 3-4 times in the previous year, comorbid cardiovascular and endocrine system diseases, failure to take regular medication for COPD, application of non-invasive ventilation machines, believing that their current health condition has deteriorated, believing that the current COVID-19 vaccine is not safe, medical staff not specifying whether they would recommend vaccination against COVID-19, medical staff not recommending the COVID-19 vaccine, and fear of adverse reactions and aggravation of COPD. Patients with COPD had a high COVID-19 vaccination rate in China, whereas patients with pneumonia, influenza, and herpes zoster had a low vaccination rate. Improving the patients' understanding of the safety and effectiveness of the vaccine and promoting effective communication between medical staff and patients would help increase the vaccination rate of patients with COPD.

Associations of proton pump inhibitors with susceptibility to influenza, pneumonia, and COVID-19: Evidence from a large population-based cohort study

Background

Adverse effects of proton pump inhibitors (PPIs) have raised wide concerns. The association of PPIs with influenza is unexplored, while that with pneumonia or COVID-19 remains controversial. Our study aims to evaluate whether PPI use increases the risks of these respiratory infections.

Methods

The current study included 160,923 eligible participants at baseline who completed questionnaires on medication use, which included PPI or histamine-2 receptor antagonist (H2RA), from the UK Biobank. Cox proportional hazards regression and propensity score-matching analyses were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs).

Results

Comparisons with H2RA users were tested. PPI use was associated with increased risks of developing influenza (HR 1.32, 95% CI 1.12-1.56) and pneumonia (hazard ratio [HR] 1.42, 95% confidence interval [CI] 1.26-1.59). In contrast, the risk of COVID-19 infection was not significant with regular PPI use (HR 1.08, 95% CI 0.99-1.17), while the risks of severe COVID-19 (HR 1.19. 95% CI 1.11-1.27) and mortality (HR 1.37. 95% CI 1.29-1.46) were increased. However, when compared with H2RA users, PPI users were associated with a higher risk of influenza (HR 1.74, 95% CI 1.19-2.54), but the risks with pneumonia or COVID-19-related outcomes were not evident.

Conclusions

PPI users are associated with increased risks of influenza, pneumonia, as well as COVID-19 severity and mortality compared to non-users, while the effects on pneumonia or COVID-19-related outcomes under PPI use were attenuated when compared to the use of H2RAs. Appropriate use of PPIs based on comprehensive evaluation is required.

Funding

This work is supported by the National Natural Science Foundation of China (82171698, 82170561, 81300279, 81741067, 82100238), the Program for High-level Foreign Expert Introduction of China (G2022030047L), the Natural Science Foundation for Distinguished Young Scholars of Guangdong Province (2021B1515020003), the Guangdong Basic and Applied Basic Research Foundation (2022A1515012081), the Foreign Distinguished Teacher Program of Guangdong Science and Technology Department (KD0120220129), the Climbing Program of Introduced Talents and High-level Hospital Construction Project of Guangdong Provincial People's Hospital (DFJH201923, DFJH201803, KJ012019099, KJ012021143, KY012021183), and in part by VA Clinical Merit and ASGE clinical research funds (FWL).

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.

Chronic cough diagnosis, treatment, and referral practices among family physicians in the United States: a survey study

BACKGROUND

Cough is one of the most common presenting problems for patients in primary care and is largely managed in primary care clinical settings. Family physicians' familiarity with chronic cough guidelines and the extent to which these guidelines translate into everyday practice have not been well described. The objective of this study was to characterize current diagnosis, treatment, and referral practices among family physicians and to identify potentially impactful strategies to optimize chronic cough management in primary care.

METHODS

We conducted a cross-sectional survey of 5,000 family physicians to explore diagnosis, treatment, and referral practices related to chronic cough management in adults in primary care. Respondents completed the survey via paper or online. The outcome measures were self-reported numeric ratings and responses related to the survey elements.

RESULTS

588 surveys were completed (11.8% response rate). About half (49.6%) of respondents defined chronic cough in a manner consistent with the American College of Chest Physicians (ACCP) chronic cough guidelines, with the rest differing in opinion primarily regarding duration of symptom presentation. Respondents reported trying to rule out most common causes of chronic cough themselves before referring (mean 3.41 on a 4-point scale where 4 is "describes me completely") and indicated a desire for more resources to help them manage and treat chronic cough. Years in practice and rural/urban setting influenced diagnosis and referral practices.

CONCLUSIONS

Family physicians see chronic cough as a complicated condition that can be and is often diagnosed and treated entirely in a primary care setting. They also value the ability to refer in complex cases. Our results support that family physicians provide evidence-based management of chronic cough.

Quality of Life in Adults with Chronic Cough: A Mixed Methods Study Informing the Development of a Quantitative Patient Preference Study

OBJECTIVES

This study aimed to describe quality of life for patients with chronic cough (CC) and identify meaningful attributes that affect patient treatment preferences to inform the design of a quantitative preference study.

METHODS

Eligible patients (≥ 18 years) with a CC (> 8 weeks) participated in qualitative interviews with two defined steps. Step one: concept elicitation and bidding games were used to collect descriptions of patient experiences with CC and identify important CC-related attributes. Step two: attributes were confirmed using concept elicitation and bidding games and prioritized using structured card sort activities. Purposive sampling ensured diversity of patient experiences. Qualitative content analysis was used to analyze participant narratives, and descriptive statistics were used to summarize card sort results. This study follows a fully mixed concurrent dominant status design, with qualitative (dominant) and quantitative components.

RESULTS

A total of 20 participants were interviewed with a mean age of 61.4 years (range 24-79 years). Coughing episodes, described as intense consecutive coughs that made catching breath difficult, were important to most participants (n = 17). Participants emphasized the emotional impact of episodes including feelings of uncertainty, loss of control, self-consciousness, and fear. Severity of CC was most often judged by frequency (n = 11) and intensity (n = 12) of cough. Daily, physical, or social activities were impacted for most participants. Impact on sleep (n = 14) included waking during the night, difficulty falling asleep, and daytime fatigue. Medication-related taste disturbances were an important consideration for what participants were willing to accept in exchange for cough relief.

CONCLUSIONS

This study emphasizes the importance of coughing episodes for adults with CC and provides initial evidence that taste alterations are an important component of patient treatment decisions for CC.

Clinical Parameters of the Speech-Language Pathology Assessment of the Chronic Cough: A Scoping Review

OBJECTIVE

to map the clinical parameters used in the speech-language pathology assessment of the chronic cough.

METHODS

a scoping review was performed to answer the clinical question: "What are the clinical parameters included in the speech-language pathology assessment of patients with chronic cough?" Evidence was searched by electronic and manual search. The electronic search included: MEDLINE, Cochrane Library, EMBASE, Web of Science, SCOPUS, and LILACS. Each database had a specific search strategy. The manual search included Journal of Voice, Chest, and Thorax, Brazilian Library of Theses and Dissertations, Open Grey, and Clinical Trials, in addition to scanning the references of the included studies. The extracted data considered information regarding the publication, sample, assessment, and measures used when assessing chronic cough.

RESULTS

the electronic search found 289 studies; the manual search found 1036 studies; 12 were selected for the present study. The most used assessments were: self-assessment (75%), aerodynamic analysis (66.67%), the perceptual auditory judgment of the voice quality (58.33%), acoustic analysis of the voice (41.67%), cough frequency, and cough threshold (41.67%) and electroglottography (25%).

CONCLUSIONS

the subjective instruments were used more frequently, while specific objective instruments, which are recent, were used less frequently. Complementary assessments such as vocal assessment, have been frequently used, also, with no other parameter. A lack of homogeneity was identified in the speech-language pathology assessment and measures of patients with chronic cough, thus, the comparison among studies and clinical analysis is difficult.

The diagnostic impact of fractional exhaled nitric oxide for asthmatic cough in nontuberculous mycobacterial pulmonary disease

BACKGROUND

Measurement of exhaled nitric oxide (FeNO) is a potentially useful diagnostic test for asthma. However, no study has explored the relationship between FeNO and respiratory symptoms of nontuberculous mycobacterial pulmonary disease (NTM-PD) complicated with asthma. The objective of this study was to assess the utility of measuring FeNO levels in patients with NTM-PD complicated by asthma.

METHODS

In this single-center retrospective cohort study, 140 NTM-PD patients with FeNO measured were enrolled. We selected NTM-PD patients who complicated with asthma as the NTM+BA group, defined using the following criteria: NTM patients with symptoms consistent with asthma, and NTM patients with symptomatic improvement after diagnostic therapy with ICS ± a long-acting beta 2-agonist (LABA). We then calculated a diagnostic cutoff point to distinguish between the NTM+BA groups and the NTM groups (all others). High-resolution computed tomography (HRCT) images were evaluated using the CT scoring system and their association with FeNO was examined.

RESULTS

A total of 89 patients were included in the study. (31 in the NTM+BA group and 58 in the NTM group). Compared with the NTM group, the NTM+BA group had higher rates of allergic disease (51.6% vs. 22.4%; p=0.0085) and higher FeNO values (median, 23 [interquartile range {IQR}, 15.0-43.0] ppb vs. median, 17 [IQR, 11.8-23.0] ppb; p=0.015). With diagnostic asthma care using mainly ICS/LABA with reference to the FeNO, most patients (91.0%, 20/22) in the NTM-preceding subgroup in the NTM+BA group demonstrated a prompt improvement of their symptoms and AFB culture findings did not worsen (Culture positive rate (%): Pre-treatment: 59.1% vs. Post-treatment: 40.9%, p=0.3660) at 6 months after starting diagnostic therapy. The optimal diagnostic cutoff point of FeNO to distinguish between the two groups was calculated as 21.5 ppb by the ROC curve (sensitivity 75%, specificity 71.93%, p<0.0001; area under the curve: 0.7989). No significant correlation was observed between FeNO and the severity of CT images in the patients.

CONCLUSIONS

A certain number of patients with NTM-PD showed exacerbated respiratory symptoms due to asthmatic complications. Elevated FeNO levels suggest asthma complications, even in patients with NTM.

Chronic Bronchitis in Children and Adults: Definitions, Pathophysiology, Prevalence, Risk Factors, and Consequences

The complex nature of chronic bronchitis (CB) and changing definitions have contributed to challenges in understanding its aetiology and burden. In children, CB is characterised by persistent airway inflammation often linked to bacterial infections and is therefore termed "protracted bacterial bronchitis" (PBB). Longitudinal studies suggest that CB in childhood persists into adulthood in a subgroup. It can also be associated with future chronic respiratory diseases including asthma, bronchiectasis, and chronic obstructive pulmonary disease (COPD). Adult CB is traditionally associated with smoking, occupational exposures, and lower socioeconomic status. The interplay between risk factors, childhood CB, adult CB, and other chronic respiratory diseases is intricate, requiring comprehensive longitudinal studies for a clearer understanding of the natural history of CB across the lifespan. Such longitudinal studies have been scarce to date given the logistic challenges of maintaining them over time. In this review, we summarise current evidence on the evolution of the definitions, pathophysiology, risk factors, and consequences of childhood and adulthood chronic bronchitis.

Characterization of Codeine Treatment Responders Among Patients with Refractory or Unexplained Chronic Cough: A Prospective Real-World Cohort Study

PURPOSE

Codeine is a narcotic antitussive often considered for managing patients with refractory or unexplained chronic cough. This study aimed to evaluate the proportion and characteristics of patients who responded to codeine treatment in real-world practice.

METHODS

Data from the Korean Chronic Cough Registry, a multicenter prospective cohort study, were analyzed. Physicians assessed the response to codeine based on the timing and degree of improvement after treatment initiation. Follow-up assessments included the Leicester Cough Questionnaire and cough severity visual analog scale at six months. In a subset of subjects, objective cough frequency was evaluated following the initiation of codeine treatment.

RESULTS

Of 305 patients, 124 (40.7%) responded to treatments based on anatomic diagnostic protocols, while 181 (59.3%) remained unexplained or refractory to etiological treatments. Fifty-one subjects (16.7%) were classified as codeine treatment responders (those showing a rapid and clear response), 57 (18.7%) as partial responders, and 62 (20.3%) as non-responders. Codeine responders showed rapid improvement in objective cough frequency and severity scores within a week of the treatment. At 6 months, responders showed significantly improved scores in cough scores, compared to non-responders. Several baseline parameters were associated with a more favorable treatment response, including older age, non-productive cough, and the absence of heartburn.

CONCLUSIONS

Approximately 60% of chronic cough patients in specialist clinics may require antitussive drugs. While codeine benefits some, only a limited proportion (about 20%) of patients may experience rapid and significant improvement. This underscores the urgent need for new antitussive drugs to address these unmet clinical needs.

Explainable artificial intelligence for cough-related quality of life impairment prediction in asthmatic patients

Explainable Artificial Intelligence (XAI) is becoming a disruptive trend in healthcare, allowing for transparency and interpretability of autonomous decision-making. In this study, we present an innovative application of a rule-based classification model to identify the main causes of chronic cough-related quality of life (QoL) impairment in a cohort of asthmatic patients. The proposed approach first involves the design of a suitable symptoms questionnaire and the subsequent analyses via XAI. Specifically, feature ranking, derived from statistically validated decision rules, helped in automatically identifying the main factors influencing an impaired QoL: pharynx/larynx and upper airways when asthma is under control, and asthma itself and digestive trait when asthma is not controlled. Moreover, the obtained if-then rules identified specific thresholds on the symptoms associated to the impaired QoL. These results, by finding priorities among symptoms, may prove helpful in supporting physicians in the choice of the most adequate diagnostic/therapeutic plan.

[Chronic cough in adult patients-evidence-based approach]

Approximately 10% of the population suffer from a cough lasting longer than 8 weeks. Compared to acute cough, which usually occurs in the context of banal respiratory tract infections, the differential diagnoses of chronic cough require an increased use of diagnostic tests and thus a structured, evidence-based approach according to current international guidelines. A targeted history (smoking status, medication, previous diseases) and ENT status are always followed by chest x‑ray and pulmonary function tests before extended diagnostics. In the case of angiotensin-converting enzyme (ACE) inhibitor use and unremarkable physical examination, a drug discontinuation test can be carried out first. In case of inconspicuous findings, a disease entity that can be treated empirically such as upper airway cough syndrome is most likely. If the cough remains unexplained, cough suppression techniques, physiotherapy or speech therapy should be sought before off-label-use of medication.

Potassium-Competitive Acid Blocker Versus Proton Pump Inhibitor: A Pilot Study on Comparable Efficacy in the Treatment of Gastroesophageal Reflux-Related Cough

Acid inhibitors have been considered in treating gastroesophageal reflux-related cough (GERC). Compared to proton pump inhibitors (PPIs), potassium-competitive acid blockers (P-CABs) have more potent and durable effects on anti-acid secretion. However, whether vonoprazan and esomeprazole have different therapeutic effects on GERC remains unknown. Patients diagnosed with GERC were enrolled in our study and randomly treated with vonoprazan (20 mg, once daily, P-CAB) or esomeprazole (20 mg, twice daily, PPI) for two months. A prokinetic agent was also administered. Patients were followed up once a month. Cough severity visual analogue scale (VAS) was measured as the primary outcome, while cough symptom score (CSS) and scores for cough-related quality-of-life or reflux-related symptoms were the secondary endpoints. A total of 50 patients completed the study, with 25 patients in each group. P-CAB and PPI groups showed similar decreases in cough severity VAS and CSS scores after the 2-month treatment (all P < 0.001). For quality-of-life, the Leicester Cough Questionnaire (LCQ) score increased significantly from baseline in both groups, but the P-CAB group had greater improvement and a higher LCQ score in month 2 (all P ≤ 0.05). For reflux-related symptoms, the Hull Airway Reflux Questionnaire (HARQ) score declined substantially over time in the P-CAB group, while the reflux symptom index (RSI) score decreased in both groups. The P-CAB group tended to have a lower HARQ (P = 0.051) and RSI (P = 0.069) scores in month 2. In conclusion, vonoprazan may be comparable to esomeprazole in cough symptom relief in GERC during the 2-month treatment period, but possibly provides better gains on classic reflux symptoms and quality-of-life. The long-term efficacy of P-CABs on GERC may be worth further exploration. Trial Registration: Chinese Clinical Trial Registry Identifier: ChiCTR2200067089.

Chronic Cough: Characterizing and Quantifying Burden in Adults Using a Nationwide Electronic Health Records Database

Chronic cough is a common condition; until recently, no International Classification of Diseases (ICD) code for chronic cough existed; therefore, the true scope and burden of chronic cough is unclear. Using established algorithms, we examined chronic cough patients and their risk profiles, recurrent cough episodes, and subsequent 1-year health care utilization in the nationwide Cerner EHR data resource, compared with those with acute cough. An ICD-based algorithm was applied to the Cerner Health Facts EHR database to derive a phenotype of chronic cough defined as three ICD-based "cough" encounters 14-days apart over a 56-to-120-day period from 2015 to 2017. Demographics, comorbidities, and outcomes (1-year outpatient, emergency, and inpatient encounters) were collected for the chronic cough cohort and acute cough cohort. The chronic cough cohort was 61.5% female, 70.4% white, and 15.2% African American, with 13.7% being of Asian, Native American, or unknown race. Compared with the acute cough cohort, chronic cough patients were more likely to be older, female, and have chronic pulmonary disease, obesity, and depression. Predictors of recurrent chronic cough were older age and race. Those with chronic cough had more outpatient (2.48 ± 2.10 vs. 1.48 ± 0.99; SMD = 0.94), emergency (1.90 ± 2.26 vs. 1.23 ± 0.68; SMD = 0.82), and inpatient (1.11 ± 0.36 vs. 1.05 ± 0.24, SMD = 0.24) encounters compared with acute cough. While EHR-based data may provide a useful resource to identify chronic cough phenotypes, supplementary data approaches and screening methods for chronic cough can further identify the scope of the problem.

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.

Patient preferences for the treatment of chronic cough: a discrete choice experiment

BACKGROUND

Chronic cough is common, negatively affects quality of life and has limited treatment options. Inhibition of purinergic signalling is a promising therapeutic approach but is associated with taste-related adverse effects. Little is known about treatment preferences from the perspective of patients with chronic cough, such as trade-offs between efficacy and side effect.

METHODS

Patients with chronic cough completed an online discrete choice experiment survey in which they answered a series of questions requiring a choice between two constructed treatment options characterised by varying attribute levels. Selection of cough and taste-related attributes was informed by qualitative interviews and clinical trial data. Logit-based models were used to analyse resulting choice data.

RESULTS

The discrete choice experiment survey was completed by 472 participants with chronic cough. Among study attributes, frequency of intense cough attacks was the most important to participants, followed by taste change, frequency of night-time coughing and frequency of daytime coughing. To accept the least preferred taste disturbance of a bitter, metallic, chalky or oily taste change, participants required either: (1) elimination of night-time cough along with a slight reduction in daytime cough; (2) elimination of daytime cough along with a pronounced reduction in night-time or (3) reduction in intense cough attacks from 7 to 2 times per week. Two distinct preference patterns were identified, each placing different importance on efficacy versus side effect trade-offs.

CONCLUSIONS

Participants with chronic cough were willing to accept some taste disturbances in exchange for improved efficacy of chronic cough treatments. Knowledge of patient preferences can facilitate shared decision-making.

Cough in Children and Adults: Diagnosis, Assessment and Management (CICADA). Summary of an updated position statement on chronic cough in Australia

INTRODUCTION

Cough is the most common symptom leading to medical consultation. Chronic cough results in significant health care costs, impairs quality of life, and may indicate the presence of a serious underlying condition. Here, we present a summary of an updated position statement on cough management in the clinical consultation.

MAIN RECOMMENDATIONS

Assessment of children and adults requires a focused history of chronic cough to identify any red flag cough pointers that may indicate an underlying disease. Further assessment with examination should include a chest x-ray and spirometry (when age > 6 years). Separate paediatric and adult diagnostic management algorithms should be followed. Management of the underlying condition(s) should follow specific disease guidelines, as well as address adverse environmental exposures and patient/carer concerns. First Nations adults and children should be considered a high risk group. The full statement from the Thoracic Society of Australia and New Zealand and Lung Foundation Australia for managing chronic cough is available at https://lungfoundation.com.au/resources/cicada-full-position-statement.

CHANGES IN MANAGEMENT AS A RESULT OF THIS STATEMENT

Algorithms for assessment and diagnosis of adult and paediatric chronic cough are recommended. High quality evidence supports the use of child-specific chronic cough management algorithms to improve clinical outcomes, but none exist in adults. Red flags that indicate serious underlying conditions requiring investigation or referral should be identified. Early and effective treatment of chronic wet/productive cough in children is critical. Culturally specific strategies for facilitating the management of chronic cough in First Nations populations should be adopted. If the chronic cough does not resolve or is unexplained, the patient should be referred to a respiratory specialist or cough clinic.

Systematic literature review of treatments used for refractory or unexplained chronic cough in adults

BACKGROUND

Refractory or unexplained chronic cough (RCC or UCC) is difficult to manage and is usually treated by the off-label use of drugs approved for other indications.

OBJECTIVE

The objectives of this systematic literature review (SLR) were to identify and characterize the current published body of evidence for the efficacy and safety of treatments for RCC or UCC.

METHODS

The SLR was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The SLRs pre-defined population included patients ≥18 years of age who were diagnosed with chronic cough. The review was not restricted to any intervention type or study comparator, nor by timeframe.

RESULTS

A total of 20 eligible publications from 19 unique trials were included. Seventeen of these trials were randomized controlled trials and most (14/17) were placebo-controlled. There was considerable variability between trials in the definition of RCC or UCC, participant exclusion and inclusion criteria, outcome measurement timepoints, and the safety and efficacy outcomes assessed. Several trials identified significant improvements in cough frequency, severity, or health-related quality of life measures while participants were on treatment, although these improvements did not persist in any of the studies that included a post-treatment follow-up timepoint.

CONCLUSIONS

In the absence of an approved therapy, placebo remains the most common comparator in trials of potential RCC or UCC treatments. The between-study comparability of the published evidence is limited by heterogeneity of study design, study populations, and outcomes measures, as well as by concerns regarding study size and risk of bias.

A 39-Year-Old Man With Refractory Chronic Cough Accompanied by Regurgitation and Belching

CASE PRESENTATION

A 39-year-old man who did not smoke was admitted to the hospital with recurrent cough for 1 year, accompanied by sputum expectoration (with a small amount of white phlegm), acid regurgitation, and belching. Nasal symptoms or other cough-related contributing factors were denied. The patient reported that his cough mainly occurred at nighttime and was aggravated in the supine position. Vomiting could occur when the cough was violent. He denied fever, dysphonia, chest tightness, wheezing, chest pain and hemoptysis, abdominal pain, and bloating. The patient had initially presented to the local hospital and underwent a chest CT scan. The chest CT scan showed slight and scattered patchy infiltration in bilateral lung fields and without other significant pulmonary lesions. Anti-infective treatment was administered but was not effective for ameliorating the cough symptoms. He then received an inhaled corticosteroid, antihistamines, antileukotriene agents, or proton pump inhibitors for 6 months. However, all these treatments failed to alleviate the patient's cough. He had a history of hypertension and hyperlipidemia for > 10 years and was treated with valsartan (an angiotensin II receptor blocker) and atorvastatin. In the past year, the patient had lost 10 kg of weight, and his current BMI was 27.72 kg/m2.

Chronic cough associated with COPD exacerbation, pneumonia and death in the general population

Background

Chronic cough affects up to 10% of the general population and was previously perceived as a comorbidity of underlying conditions, but is nowadays classified as a disease in its own entity that could confer increased risk of morbidity and mortality. We tested the hypothesis that chronic cough is associated with increased risk of COPD exacerbation, pneumonia and all-cause mortality in the general population.

Methods

We identified 2801 individuals with chronic cough, defined as cough lasting >8 weeks, among 44 756 randomly selected individuals from the Copenhagen General Population Study, and recorded COPD exacerbations, pneumonia and all-cause mortality during follow-up.

Results

During up to 5.9 years of follow-up (median 3.4 years), 173 individuals experienced COPD exacerbation, 767 experienced pneumonia and 894 individuals died. Individuals with chronic cough versus those without had cumulative incidences at age 80 years of 12% versus 3% for COPD exacerbation, 30% versus 15% for pneumonia, and 25% versus 13% for death from all causes. After adjustment for age, sex and smoking, individuals with chronic cough versus those without had adjusted hazard ratios of 4.6 (95% CI 2.9-7.2) for COPD exacerbation, 2.2 (1.7-2.7) for pneumonia and 1.7 (1.4-2.0) for all-cause mortality. Among current smokers aged >60 years with airflow limitation, those with versus without chronic cough had an absolute 5-year risk of 10% versus 4% for COPD exacerbation, 16% versus 8% for pneumonia and 19% versus 12% for all-cause mortality.

Conclusion

Chronic cough is associated with higher risks of COPD exacerbation, pneumonia and death, independent of airflow limitation and smoking.

Assessment and Management of Cough in Idiopathic Pulmonary Fibrosis: A Narrative Review

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fatal disease with an unknown cause. It is characterized by symptoms such as cough and breathlessness, which significantly impact patients' quality of life. Cough, in particular, has emerged as a burdensome symptom for individuals with IPF. The etiology of cough in IPF patients is believed to be complex, involving factors related to the disease itself, such as increased sensitivity of cough nerves, lung structural changes, inflammation, and genetic factors, as well as comorbidities and medication effects. Unfortunately, effective treatment options for cough in IPF remain limited, often relying on empirical approaches based on studies involving chronic cough patients in general and the personal experience of physicians. Medications such as opioids and neuromodulators are commonly prescribed but have shown suboptimal efficacy, imposing significant physical, psychological, and economic burdens on patients. However, there is hope on the horizon, as specific purinergic P2 receptor ligand-gated ion channel (P2X3) inhibitors have demonstrated promising antitussive effects in ongoing clinical trials. This review aims to provide a comprehensive overview of the evaluation and management of cough in IPF patients, as well as highlight emerging pharmacological and non-pharmacological approaches that target the cough reflex and are currently being investigated in clinical settings.

Safety and efficacy of P2X3 receptor antagonist for the treatment of refractory or unexplained chronic cough: A systematic review and meta-analysis of 11 randomized controlled trials

BACKGROUND AND OBJECTIVES

Chronic refractory cough is a challenging condition that requires a thorough evaluation and management approach. P2X3 receptors that are ATP-dependent play an important part in nerve fiber sensitization and pathological pain pathways. We conducted this systematic review and meta-analysis to determine the long-term safety and efficacy of P2X3 receptor antagonist drugs in chronic cough.

METHODS

We systematically searched PubMed, Scopus, Web of Science, and Embase to identify all relevant published studies through January 15, 2023 that assessed P2X3 antagonists in chronic cough. The protocol was registered in the PROSPERO database with ID: CRD42023422408. Efficacy outcomes were awake (daytime) cough frequency, night cough frequency, 24-h cough frequency, Cough Severity Diary, and total Leicester Cough Questionnaire score. We used the random-effect model to pool the data using RStudio and CMA software.

RESULTS

A total of 11 randomized controlled trials comprising 1350 patients receiving a p2x3 antagonist compared to the placebo group were included in this meta-analysis. A significant decrease in 24-h cough frequency (MD = -4.99, 95% CI [-7.15 to -2.82], P < 0.01), awake (daytime) cough frequency (MD = -7.18, 95% CI [-9.98 to 4.37], P < 0.01), and total Leicester Cough Questionnaire score (MD = 1.74, 95% CI [1.02 to 2.46], P < 0.01) exhibited between the P2X3 antagonist and placebo groups. The frequency of the night cough showed an insignificant difference between the two groups. According to the safety, drug-related adverse events, dysgeusia, hypogeusia, and ageusia significantly increased between the P2X3 antagonist and placebo groups.

CONCLUSION

P2X3 receptor antagonists are promising drugs for treating chronic cough by significantly reducing the frequency, severity, and quality. Some potential side effects may include drug-related adverse events such as hypogeusia, ageusia, and dysgeusia.

Diagnostic Criteria and the Decision to Treat Nontuberculous Mycobacterial Pulmonary Disease

The diagnosis of nontuberculous mycobacterial (NTM) pulmonary disease is based on three criteria: patient's symptoms, radiographic findings, and microbiologic results. The microbiologic criterion is the most complicated because it requires more than one positive sputum acid-fast bacilli culture. Clinicians are challenged to apply the diagnostic criteria in the context of variable patient symptoms, NTM pathogenicity, and host susceptibility. The decision to treat NTM pulmonary disease entails assessment of the risks and benefits of therapy and the patient's wishes and ability to receive treatment.

Recurrent Cough in the Elderly: A Forgotten Entity

INTRODUCTION

Recurrent cough is little researched in adults. We investigated the prevalence, risk factors, and consequences of recurrent cough, and compared the results to those of isolated chronic cough.

METHODS

Cross-sectional email survey in an elderly community-based population. Recurrent cough was defined as ≥ 3 cough episodes within one year (each lasting ≥ 1 week) and no current chronic cough. Isolated chronic cough was defined as current cough lasting ≥ 8 weeks and no recurrent cough.

RESULTS

The prevalence of recurrent cough was 3.8% among all respondents (n = 5983). Recurrent cough was associated with asthma (aOR 3.32 (95% CI 2.13-5.18)), chronic rhinosinusitis (2.91 (1.89-4.46)), family history of chronic cough (2.59 (1.88-3.56)), analgesic intolerance (2.13 (1.27-3.57)), male gender (1.92 (1.39-2.66)), gastro-esophageal reflux disease (1.73 (1.21-2.47)), obstructive sleep apnoea (1.69 (1.23-2.32)), symptom sum (1.12 per symptom (1.03-1.22)), and younger age (0.96 per year (0.93-1.00)). Isolated chronic cough was associated with chronic rhinosinusitis (3.45 (2.39-4.97)), asthma (2.17 (1.38-3.41), gastro-esophageal reflux disease (1.80 (1.32-2.47)), family history of chronic cough (1.80 (1.35-2.41)), obstructive sleep apnoea (1.49 (1.12-2.00)), symptom sum (1.18 per symptom (1.10-1.27)), and body mass index (0.96 per unit (0.93-1.00)). Among subjects with recurrent and isolated chronic cough, the prevalence of depressive symptoms were 7.7% and 4.2%, p = 0.11, the Leicester Cough Questionnaire total scores 15.2 (14.6-15.8) and 16.3 (16.0-16.6), P = 0.001, and the mean number of yearly cough-related doctor`s visits 0.58 (0.45-0.71) and 0.36 (0.19-0.53), P = 0.007, respectively.

CONCLUSION

The risk factors and consequences of recurrent and isolated chronic cough were comparable. Recurrent cough seems beneficial to address in cough evaluation.

Predictors of treatment response to pregabalin in unexplained or refractory chronic cough

BACKGROUND

Patients with chronic cough (>8 weeks) often remain symptomatic after appropriate investigations and therapeutic trials. Prior research has shown a benefit in certain individuals from pregabalin, but clinical improvement is quite unpredictable and variable.

OBJECTIVE

The main objective of this study was to identify the demographic and clinical characteristics associated with a higher likelihood of cough improvement with a trial of pregabalin therapy.

METHODS

50 consecutive patients with chronic cough were enrolled in this prospective cohort study. Subjects were prescribed pregabalin 75 mg oral qhs for 4 weeks followed by 75 mg oral bid. Leicester Cough Questionnaire (LCQ) was completed at treatment initiation and after 3 months of therapy. A comparison was performed between treatment responders (LCQ total score improvement ≥1.3) and non-responders.

RESULTS

56% of patients reported a LCQ total score improvement ≥1.3 (minimal clinically important difference). Responders to pregabalin therapy were more likely to have refractory (with underlying pulmonary disease) versus unexplained chronic cough (p = 0.01). Patients with significant improvement were also on average more symptomatic at baseline (mean LCQ total score 10.2 versus 13.0, p < 0.01). No significant relationship was identified with age, gender, body mass index, history of anxiety and/or depression, cigarette smoking history, or cough duration (p > 0.05). The unexplained chronic cough group had a strong female predominance (85.7% versus 40.9% for refractory cough, p < 0.01).

CONCLUSION

This is the first study that has investigated clinical predictors of treatment response to pregabalin in chronic cough patients. Further research is needed to develop therapies for subjects who do not improve with currently available neuromodulating medications.