Prevalence, pathogenesis, and causes of chronic cough

As a rare cause of drug-induced cough: topiramate

The most common causes of chronic cough in nonsmokers are postnasal drip syndrome, asthma, and gastroesophageal reflux disease. Drugs are also important in the etiology of resistant cough. Most common drugs inducing cough are the ACE inhibitors. Many drugs other than ACE inhibitors can also cause dry cough and one among them is topiramate. It is a new generation, efficacy-proved antiepileptic drug that is used widely for migraine prophylaxis in many countries. Most common adverse events of topiramate are paresthesia, cognitive symptoms, fatigue, insomnia, nausea, loss of apetite, anxiety, and dizziness. There is only one case report about topiramate associated cough in the literature. The present report refers to a patient, presenting with cough who is on topiramate treatment for migraine prophylaxis.

[Managements of chronic cough in general medicine and requirements of general practitioners]

Chronic cough represents a persistent dilemma, for general practitioner (GP), inducing a lot of medical investigations. Few data are available about French GP practice and their expectancy from cough specialists. We studied management in primary care and impressions of GP of patients with chronic cough. Thirty-four patients were studied. They were mostly women, mean age was above 50 years-old, and the waste majority of patients were non-smokers. Halftime, the symptom was persistent (more than 6 months), had promoted numerous medical consultations (more than five). Drugs were prescribed since the first visit for the majority of patients, principally cough-sedation drugs, steroids and bronchodilatators. A chest radiography was realized in almost all patients. Advices were asked (with a decreasing frequency) to physicians specialized in: ear-nose-throat or respiratory, gastroenterology, allergy, or cardiology. The majority of patients were satisfied of their GP, despite persistent symptoms. From the point of the GP, chronic cough remains a relentless dilemma. Their main purpose, when they addressed their patient to a specialized physician, was to obtain an etiologic diagnosis. When they were asked "which tool will be more adequate for you in the next future?", the preferred response was "a simple etiologic algorithm". Despite persistent symptoms, inducing furthers medical consultations, the main ask from GP was to promote a simple etiologic algorithm.

Chronic cough and OSA: a new association?

Chronic cough is defined as cough lasting more than 2 months. Common causes for chronic cough in nonsmokers with normal chest radiographs and pulmonary functions include gastroesophageal reflux disease (GERD), cough-variant asthma (CVA), and upper airway cough syndrome (UACS). Current guidelines recommend diagnosing the etiology of chronic cough based upon the results of therapy for suspected GERD, CVA, and UACS. Despite following current recommendations for diagnosis and treatment, the cause for a significant proportion of chronic cough remains unexplained.Recent reports indicate the resolution of chronic cough following treatment of concomitantly diagnosed obstructive sleep apnea (OSA). Whether this represents a co-occurrence of two commonly prevalent disorders or a pathophysiologic relationship between OSA and cough remains unknown. This review offers insights into a pathophysiologic link between OSA and the commonly purported etiologies for cough, namely, GERD, UACS, and CVA. In addition, evidence for a relationship between airway inflammation that can trigger or perpetuate cough and OSA is discussed. This review explores mechanisms by which nocturnal continuous positive airway therapy resolves cough by improving underlying airway inflammation secondary to OSA and impacts upon GERD, CVA, and UACS.

The validity and precision of the Leicester Cough Questionnaire in COPD patients with chronic cough

Background

A validated instrument to assess the effects of chronic cough on health status in patients with chronic obstructive pulmonary disease (COPD) is currently not available. The Leicester Cough Questionnaire (LCQ) is a cough-specific health status questionnaire which is originally validated for a population of general patients presenting with chronic cough. We examined the psychometric performance of the LCQ in patients with COPD and chronic productive cough.

Methods

Concurrent validity, internal consistency, reproducibility and responsiveness were determined. The St. George's Respiratory Questionnaire (SGRQ) and the Short Form-36 (SF-36) were used as external criteria. Questionnaires were completed at the start of the study. After 2 and 12 weeks the LCQ was repeated, together with a global rating of change.

Results

In total 54 patients were included. Concurrent validity analysis showed significant correlations between corresponding domains of the LCQ and the SGRQ (r_s -0.31 to -0.60). Corresponding domains of the LCQ and the SF-36 showed weaker correlations (r_s 0.04 to 0.41). Internal consistency was adequate for two of the three domains (Cronbach's α 0.74 - 0.86). Test-retest reliability in stable patients was high (intraclass correlation coefficients 0.79 - 0.93). The mean difference after two weeks was 0.73 (± 1.75). Responsiveness analysis indicated that the LCQ was able to detect changes after 12 weeks.

Conclusion

The LCQ is a valid, reliable, responsive instrument to measure health status in COPD patients with chronic productive cough.

Trial Registration

ClinicalTrials.gov: NCT01071161

Effect of cigarette smoking on cough reflex induced by TRPV1 and TRPA1 stimulations

BACKGROUND

Recent studies have shown that neurogenic inflammation induced by cigarette smoke is inhibited by TRPA1 antagonist, but not by TRPV1 antagonist. Since cough reflex sensitivity is known to be modified by smoking status, we investigated the effects of cigarette smoking on TRPA1- and TRPV1-induced cough and urge-to-cough in healthy males.

METHODS

Twenty-six healthy never-smokers and 30 healthy current smokers were recruited via public postings. Cough reflex thresholds and urge-to-cough were evaluated by inhalation of capsaicin, a TRPV1 agonist, and cinnamaldehyde, a TRPA1 agonist. The cough reflex thresholds were defined as the lowest concentrations of capsaicin and cinnamaldehyde that elicited two or more coughs (C(2)) and five or more coughs (C(5)), respectively. The urge-to-cough was evaluated using the modified Borg scale.

RESULTS

In capsaicin-induced cough, the cough reflex thresholds, as expressed by C(2) and C(5), in current smokers were significantly higher than those in never-smokers (p<0.01 and p<0.001, respectively). The urge-to-cough log-log slopes in current smokers were significantly lower than those of never-smokers (p<0.001). There were no significant differences in the thresholds of the urge-to-cough between never-smokers and current smokers. In cinnamaldehyde-induced cough, there were no significant differences in cough reflex thresholds in C(2) and C(5) between never-smokers and current smokers, nor were there any significant differences in urge-to-cough log-log slope between never-smokers and current smokers. There were no significant differences in the thresholds of the urge-to-cough between never-smokers and current smokers.

CONCLUSION

The study suggests that smoking has a differential effect on cough responses between TRPV1 and TRPA1 stimulations.

Therapy for cough: where does it fall short?

Studies on cough have come a long way but many shortfalls still exist. These shortfalls can be attributed to: the lack of randomized controlled studies with a focus on cough; studies not using robust cough outcome measures, poor definition of target groups in studies and guidelines, the lack of safe and efficacious treatments; difficulty in defining etiological factors, and the lack of data on the predictors of response to therapies for cough dominant etiologies. Addressing shortfalls in cough therapy that focuses on improving the lives of people with cough requires a systematic approach that includes better medications, high quality studies, improved multidisciplinary guidelines and education (of both health professionals and patients). To achieve new cough therapeutics requires an improved understanding of cough in humans (i.e., not just in animals). Development of new medications without substantial adverse events is long awaited for cough.

On the psychology of cough

Neurobiological research is increasingly documenting the role of higher brain areas in cough, but little systematic behavioral research on the role of psychological factors exists. In this article we discuss the role of perceptual, attentional, cognitive, and emotional factors, learning mechanisms, self-regulation, and the role of social context. We also describe how interactions among these mechanisms can help to shed light on idiopathic cough and on placebo/nocebo effects on cough. This functional-behavioral perspective may lay the groundwork for a structured research program on the role of psychological factors in cough.

Cough management: a practical approach

Cough is one of the most common symptoms for which patients seek medical attention from primary care physicians and pulmonologists. Cough is an important defensive reflex that enhances the clearance of secretions and particles from the airways and protects the lower airways from the aspiration of foreign materials. Therapeutic suppression of cough may be either disease-specific or symptom related. The potential benefits of an early treatment of cough could include the prevention of the vicious cycle of cough. There has been a long tradition in acute cough, which is frequently due to upper respiratory tract infections, to use symptom-related anti-tussives. Suppression of cough (during chronic cough) may be achieved by disease-specific therapies, but in many patients it is often necessary to use symptomatic anti-tussives, too. According to the current guidelines of the American College of Chest Physician on "Cough Suppressants and Pharmacologic Protussive Therapy" and additional clinical trials on the most frequent anti-tussive drugs, it should be possible to diagnose and treat cough successfully in a majority of cases. Among drugs used for the symptomatic treatment of cough, peripherally acting anti-tussives such as levodropropizine and moguisteine show the highest level of benefit and should be recommended especially in children. By improving our understanding of the specific effects of these anti-tussive agents, the therapeutic use of these drugs may be refined. The present review provides a summary of the most clinically relevant anti-tussive drugs in addition to their potential mechanism of action.

Pediatric cough: what the otolaryngologist needs to know

PURPOSE OF REVIEW

Pediatric cough is a common complaint in 35% of preschool children and 9% of 7-11-year-olds. The cause of the cough is often elusive. This review article presents a framework from which to approach the pediatric patient with chronic cough.

RECENT FINDINGS

The cause of cough in the pediatric patient is often allergy, postnasal drip, asthma, or infection. The existence of cough-variant asthma has been brought into question and evidence is detailed in this article.

SUMMARY

The treatment of chronic cough in a pediatric population should be approached from a multidisciplinary team consisting of pulmonologists, gastroenterologists, allergists, immunologists and otolaryngologists. Once a specific diagnosis is determined, treatment should be specific to that diagnosis.

Chronic cough and tachycardia-induced cardiomyopathy in a patient with idiopathic frequent, monomorphic premature ventricular contractions

A 70-year-old woman presented with a 1-year history of dry cough. Extensive work-up ruled out common causes of chronic cough. She was found to have very frequent, monomorphic premature ventricular contractions (PVCs) and mild-to-moderate left ventricular systolic dysfunction. Propafenone 450 mg/day resulted in complete resolution of her cough and disappearance of PVCs within 24 hours of initiation. One month after the initiation of propafenone therapy, left ventricular ejection fraction normalized and her chronic cough resolved completely.

Supportive and palliative care of advanced nonmalignant lung disease

Supportive and palliative care is an interdisciplinary challenge with the aims of symptom relief and improvement of quality of life in end-stage patients. Main complaints of patients with advanced nonmalignant lung disease are depression and anxiety, dyspnea, pain, and coughing. The discomfort of many physicians, caregivers, and family members with discussions about end-of-life care is one obstacle for the timely initiation of palliative care and the uncertainty of the short-term prognosis in most advanced nonmalignant respiratory diseases. Early dialog about supportive care already at the onset of the patient's first symptoms and contemporaneous to life-prolonging therapy may overcome these barriers. Furthermore, continuing education for health professionals in palliative care ensures adequate palliative support. Here, we review insights into symptom control and palliative care in patients with advanced nonmalignant respiratory disease.

Should chronic catarrh patients seen in primary care be referred for further investigations?

BACKGROUND

Chronic catarrh is commonly encountered in primary care, but often presents a quandary to the clinician because the history of postnasal or pharyngeal mucus build-up is frequently at odds with the absence of physical findings. As with certain other medically mysterious syndromes, the value of often costly investigation remains unclear in both the primary and the secondary care settings. Indeed, investigation may reassure the physician more than the patient (1) and could even prove counter-productive through reinforcement of the patient's belief about the presence of significant pathology (2).

AIM

To establish the benefit of referral of chronic catarrh patients for specialist investigation.

DESIGN

A cross-sectional survey.

SETTING

A total of 138 patients referred to secondary care with chronic catarrh, postnasal drip or throat clearing in the north of England.

METHODS

Subjects completed three disease-specific symptom-scoring questionnaires (RSI, SNOT-20 and GETS). Investigations performed were saccharin clearance time, nasendoscopy, skinprick allergy testing and CT of sinuses. Results were compared with published values.

RESULTS

Catarrh patients scored highly on all three symptom questionnaires. Nasendoscopy was normal in 70% of patients, with the remainder demonstrating mostly simple mucus (20%), lymphoid tissue (6%) or mucopus (2%). Only 6 of the 136 patients tested had a prolonged saccharin clearance time greater than 30 min. The mean score of the 63 sinus CT scans obtained was 2.6 (normal range = 0-5). Of patients undergoing skinprick testing (n = 45), 30% reacted to one or more inhaled allergen. No rhinological investigation yielded results above that expected in the general population.

CONCLUSION

Chronic catarrh appears to be related more to pharyngeal symptom awareness than to pathological postnasal drip or mucus over-production. Rhinological investigations have a limited role in the management of chronic catarrh patients. The principal outcome of ENT referral is likely to be reassurance and direction towards patient self-help information.

Unusual asthma syndromes and their management

Asthma usually presents with symptoms of wheeze, dyspnoea and cough. However, clinicians should be aware of atypical presentation of this disorder when cough is the main or only symptom in conditions such as cough-variant asthma, nonasthmatic eosinophilic bronchitis and atopic cough. Early diagnosis and treatment of these conditions with inhaled corticosteroids improves symptoms in the majority of patients. Up to 10% of patients with asthma remain poorly controlled in spite of optimal standard therapy. These patients have been encompassed under the term 'treatment-refractory asthma' (TRA), have the greatest morbidity and are responsible for more than 50% of healthcare costs. In this review we discuss investigations, management and pathophysiology of the various phenotypes of atypical presentations of asthma as well as novel biological agents licensed and those that have been reported in clinical trials in terms of their efficacy and safety in TRA.

Aging deteriorated perception of urge-to-cough without changing cough reflex threshold to citric acid in female never-smokers

Background

The effect of aging on the cognitive aspect of cough has not been studied yet. The purpose of this study is to investigate the aging effect on the perception of urge-to-cough in healthy individuals.

Methods

Fourteen young, female, healthy never-smokers were recruited via public postings. Twelve elderly female healthy never-smokers were recruited from a nursing home residence. The cough reflex threshold and the urge-to-cough were evaluated by inhalation of citric acid. The cough reflex sensitivities were defined as the lowest concentration of citric acid that elicited two or more coughs (C₂) and five or more coughs (C₅). The urge-to-cough was evaluated using a modified the Borg scale.

Results

There was no significant difference in the cough reflex threshold to citric acid between young and elderly subjects. The urge-to-cough scores at the concentration of C₂ and C₅ were significantly smaller in the elderly than young subjects. The urge-to-cough log-log slope in elderly subjects (0.73 ± 0.71 point · L/g) was significantly gentler than those of young subjects (1.35 ± 0.53 point · L/g, p < 0.01). There were no significant differences in the urge-to-cough threshold estimated between young and elderly subjects.

Conclusions

The cough reflex threshold did not differ between young and elderly subjects whereas cognition of urge-to-cough was significantly decreased in elderly subjects in female never-smokers. Objective monitoring of cough might be important in the elderly people.

Prolonged bedtime bottle feeding and respiratory symptoms in infants

Background

Infants with chronic respiratory symptoms should be evaluated thoroughly because there are various causes which are different from those of children and adolescents.

Objective

This study was designed to investigate the relationship between chronic respiratory symptoms and bedtime bottle feeding in infants after the age of 6 months.

Methods

We conducted a prospective study that included 44 infants who presented with respiratory symptoms for more than 8 weeks and also had been bottle-fed during bedtime even after 6 months of age. The infants were divided into 2 groups; infants who discontinued bedtime bottle feeding and those who did not. Respiratory symptom scores were graded with a four-point scale at 0, 1, 2 and 3 months, and were compared between the 2 groups.

Results

Twenty eight infants (63.6%) stopped being bottle-fed during bedtime and 16 infants (36.4%) were still bottle-fed. The respiratory symptom scores were significantly decreased in infants who stopped bedtime bottle feeding (p = 0.0003).

Conclusion

It is suggested that prolonged bedtime bottle feeding might be one of the causes of chronic respiratory symptoms in infants.

Japanese guideline for adult asthma

Adult bronchial asthma (hereinafter, asthma) is characterized by chronic airway inflammation, reversible airway narrowing, and airway hyperresponsiveness. Long-standing asthma induces airway remodeling to cause an intractable asthma. The number of patients with asthma has increased, while the number of patients who die from asthma has decreased (1.7 per 100,000 patients in 2009). The aim of asthma treatment is to enable patients with asthma to lead a healthy life without any symptoms. A partnership between physicians and patients is indispensable for appropriate treatment. Long-term management with agents and elimination of causes and risk factors are fundamental to asthma treatment. Four steps in pharmacotherapy differentiate mild to intensive treatments; each step includes an appropriate daily dose of an inhaled corticosteroid (ICS), varying from low to high doses. Long-acting β(2) agonists (LABA), leukotriene receptor antagonists, and theophylline sustained-release preparation are recommended as concomitant drugs, while anti-IgE antibody therapy is a new choice for the most severe and persistent asthma. Inhaled β(2) agonists, aminophylline, corticosteroids, adrenaline, oxygen therapy, etc., are used as needed against acute exacerbations. Allergic rhinitis, chronic obstructive pulmonary disease (COPD), aspirin induced asthma, pregnancy, and cough variant asthma are also important factors that need to be considered.

Provision of primary care to patients with chronic cough in the community pharmacy setting

BACKGROUND

Community pharmacies are at the forefront of primary care providers and have an important role in the referral of patients to a medical practitioner for review when necessary. Chronic cough is a common disorder in the community and requires medical assessment. The proficiency of community pharmacy staff to refer patients with chronic cough is currently unknown.

OBJECTIVE

To assess the ability of community pharmacy staff to recognize and medically refer patients with a chronic nonproductive cough.

METHODS

Following ethics approval, a simulated patient study of 156 community pharmacies in Perth, Western Australia, was conducted over a 3-month period. Simulated patients presented to the pharmacy requesting treatment for a cough. The simulated patient required a referral based on a designated scenario. Demographic details, assessment questions, and advice provided were recorded by the simulated patient immediately postvisit. A logistic regression analysis was performed, with referral for medical assessment as the dependent variable.

RESULTS

Of the 155 community pharmacies included in the analysis, 38% provided appropriate medical referral. Cough suppressants were provided as therapy in 72% of all visits. Predictors of medical referral were assessment of symptom duration, medical history, current medications being taken, frequency of reliever use, and the position of the pharmacy staff member conducting the consultation. A third of community pharmacies provided appropriate primary care by recommending medical referral advice to patients with chronic cough. The majority of pharmacy staff members acquired information from the patient that suggested a need for medical referral, yet did not provide referral advice.

CONCLUSIONS

Appropriate medical referral is more likely when adequate assessment is undertaken and when a pharmacist is directly involved in the consultation. This highlights the need for pharmacies to ensure that processes are in place for patients to access the pharmacist.

Factors associated with computed tomography status in patients presenting with a history of chronic rhinosinusitis

BACKGROUND

The diagnosis of chronic rhinosinusitis (CRS) is based upon symptomatic criteria and objective measures. However, patients suspected to have CRS based on a positive history but negative endoscopies remain a diagnostic challenge. We investigated the utility of point of care computed tomography (POC-CT) in resolving this issue.

METHODS

The study group consisted of a simple random sample of 100 patients presenting with active CRS symptoms and negative endoscopies who underwent POC-CT at initial presentation. Presenting symptoms and comorbidities were correlated with CT scan results (positive/negative) using univariate and multivariate logistic regression models.

RESULTS

POC-CT was considered positive in 49% of patients. Univariate analysis revealed that patients complaining nasal obstruction were significantly more likely to have a positive scan (odds ratio [OR], 2.74; p = 0.047), while those with postnasal drip (OR, 0.44; p = 0.047) or cough (OR, 0.17; p = 0.03) were less likely to have positive scan results. In the multivariate model, these trends persisted without reaching statistical significance. Under univariate analysis, patients who were prescribed antibiotics, oral steroids, or nasal steroids at this initial visit were more likely to have had a positive CT. These trends also persisted in the multivariate model, with significance observed for the association between antibiotic prescription and a positive scan (p = 0.001).

CONCLUSION

Less than 50% of patients with active CRS symptoms had radiographic manifestations of sinus disease. Other etiologies must be considered higher in the differential for those presenting primarily with complaints referable to the throat. POC-CT averted unnecessary antibiotics in these patients.

Cough and Asthma

Cough is the most common complaint for which patients seek medical attention. Cough variant asthma (CVA) is a form of asthma, which presents solely with cough. CVA is one of the most common causes of chronic cough. More importantly, 30 to 40% of adult patients with CVA, unless adequately treated, may progress to classic asthma. CVA shares a number of pathophysiological features with classic asthma such as atopy, airway hyper-responsiveness, eosinophilic airway inflammation and various features of airway remodeling. Inhaled corticosteroids remain the most important form of treatment of CVA as they improve cough and reduce the risk of progression to classic asthma most likely through their prevention of airway remodeling and chronic airflow obstruction.

Chronic 'cough hypersensitivity syndrome': a more precise label for chronic cough

Chronic cough remains a challenge to many clinicians because there is often no diagnostic link to causation, and because indirect antitussives are largely ineffective. Chronic cough can also be a predominant symptom associated with many chronic respiratory diseases such as COPD, asthma and pulmonary fibrosis. Chronic cough itself does impair the quality of life and is associated with psychological impairment. The symptoms associated with chronic cough include persistent tickling or irritating sensation in the chest or throat, hoarse voice, dysphonia or vocal cord dysfunction. Currently, the clinical diagnosis of cough is associated with chronic cough caused by airway eosinophilic conditions such as asthma, gastrooesophageal reflux disease or post-nasal drip (or upper airway syndrome), which implies cause and effect, or with chronic cough associated with other diseases such as COPD, cancer or heart failure, that does not necessarily imply cause and effect. A recently-recognised category is idiopathic cough, with no associated or causative diagnosis. We suggest that there is a better label needed for chronic cough, that includes the common association with a hypersensitive cough response to tussive stimuli such as capsaicin or citric acid. This would invoke a hypersensitive syndrome, and there are good reasons to use a new label that would encompass the problem of chronic cough: the chronic 'cough hypersensitivity syndrome'. This would focus the problem on the cough symptomatology and lead to greater focus on understanding the mechanisms of cough sensitisation, with the ultimate aim of obtaining more effective antitussives.

Workshop: tuning the 'cough center'

The Workshop considered the mechanisms whereby the 'cough center' could be tuned by various afferent inputs. There were particular presentations on the effects of inputs from the nose, mouth, respiratory tract and lungs, cerebral cortex, somatic tissues and the pharynx. From all these sites cough induced from the lungs could be increased or decreased in its strength or modified in its pattern. Thus 'tuning' of cough could be due to the interaction of afferent inputs, or to the sensitization or desensitization of brainstem neural pathways. The pattern of response depended on the 'type' of cough being studied and, in some instances, on the timing of the sensory input into the brainstem. Cough inputs could also affect various 'non-cough' motor outputs from the brain, although this was not the main theme of the Workshop. The main conclusion was that cough is not a stereotyped output from the medullary 'cough center', but that its pattern and strength depend on many afferent inputs acting on the 'cough center'.

Theobromine and the pharmacology of cocoa

The effects of theobromine in man are underresearched, possibly owing to the assumption that it is behaviourally inert. Toxicology research in animals may appear to provide alarming results, but these cannot be extrapolated to humans for a number of reasons. Domestic animals and animals used for racing competitions need to be guarded from chocolate and cocoa-containing foods, including foods containing cocoa husks. Research ought to include caffeine as a comparative agent, and underlying mechanisms need to be further explored. Of all constituents proposed to play a role in our liking for chocolate, caffeine is the most convincing, though a role for theobromine cannot be ruled out. Most other substances are unlikely to exude a psychopharmacological effect owing to extremely low concentrations or the inability to reach the blood-brain barrier, whilst chocolate craving and addiction need to be explained by means of a culturally determined ambivalence towards chocolate.

Chronic cough and irritable larynx

BACKGROUND

Perennial rhinitis (PR), chronic rhinosinusitis (CRS), or both, asthma, and gastroesophageal reflux disease (GERD) are the most frequent triggers of chronic cough (CC). Extrathoracic airway receptors might be involved in all 3 conditions because asthma is often associated with PR/CRS and gastroesophageal refluxate might reach the upper airway. We previously found that most patients with rhinosinusitis, postnasal drip, and pharyngolaryngitis show laryngeal hyperresponsiveness (LHR; ie, vocal cord adduction on histamine challenge) that is consistent with an irritable larynx.

OBJECTIVE

We sought to evaluate the role of LHR in patients with CC.

METHODS

LHR and bronchial hyperresponsiveness (BHR) to histamine were assessed in 372 patients with CC and in 52 asthmatic control subjects without cough (asthma/CC-). In 172 patients the challenge was repeated after treatment for the underlying cause of cough.

RESULTS

The primary trigger of CC was PR/CRS in 208 (56%) patients, asthma in 41 (11%) patients (asthma/CC+), GERD in 62 (17%) patients, and unexplained chronic cough (UNEX) in 61 (16%) patients. LHR prevalence was 76% in patients with PR/CRS, 77% in patients with GERD, 66% in patients with UNEX, 93% in asthma/CC+ patients, and 11% in asthma/CC- patients. Upper airway disease was found in most (95%) asthma/CC+ patients and in 6% of asthma/CC- patients. BHR discriminated asthmatic patients and atopy discriminated patients with PR/CRS from patients with GERD and UNEX. Absence of LHR discriminated asthmatic patients without cough. After treatment, LHR resolved in 63% of the patients and improved in 11%, and BHR resolved in 57% and improved in 18%.

CONCLUSIONS

An irritable larynx is common in patients with CC and indicates upper airway involvement, whether from rhinitis/sinusitis, gastric reflux, or idiopathic sensory neuropathy.

The epidemiology of cough

Cough is a common symptom that affects a large proportion of the general population, but has been somewhat neglected in the epidemiological literature in the recent years. Various types of coughs are described based on life-long epidemiological surveys. Using published and unpublished data from three epidemiological studies (the European Community Respiratory Health survey, the French Epidemiological study on the Genetics and environment of asthma (EGEA) and the French E3N study), some specific aspects are discussed in detail. Phenotypic heterogeneity according to chronicity, or its productive nature, or its daytime or nocturnal characteristics are discussed. The association of cough with asthma and gender is described, together with its evolution over a 12-year period. The potential for genetic studies of cough is discussed.

Systematic review of clinical trials assessing the effectiveness of ivy leaf (hedera helix) for acute upper respiratory tract infections

Introduction. Among nonantibiotic cough remedies, herbal preparations containing extracts from leaves of ivy (Hedera helix) enjoy great popularity. Objective. A systematic review to assess the effectiveness and tolerability of ivy for acute upper respiratory tract infections (URTIs). Methods. We searched for randomized controlled trials (RCTs), nonrandomized controlled clinical trials and observational studies evaluating the efficacy of ivy preparations for acute URTIs. Study quality was assessed by the Jadad score or the EPHPP tool. Results. 10 eligible studies were identified reporting on 17463 subjects. Studies were heterogeneous in design and conduct; 2 were RCTs. Three studies evaluated a combination of ivy and thyme, 7 studies investigated monopreparations of ivy. Only one RCT (n = 360) investigating an ivy/thyme combination used a placebo control and showed statistically significant superiority in reducing the frequency and duration of cough. All other studies lack a placebo control and show serious methodological flaws. They all conclude that ivy extracts are effective for reducing symptoms of URTI. Conclusion. Although all studies report that ivy extracts are effective to reduce symptoms of URTI, there is no convincing evidence due to serious methodological flaws and lack of placebo controls. The combination of ivy and thyme might be more effective but needs confirmation.

Acoustic cough-reflux associations in chronic cough: potential triggers and mechanisms

BACKGROUND & AIMS

Central sensitization is thought to play a role in chronic cough and might explain the temporal association between cough and gastroesophageal reflux (GOR) in patients in whom non-GOR causes have been excluded. Using our novel simultaneous acoustic cough recording and impedance/pH monitoring technique, we aimed to explore this further by assessing such temporal associations and their relationship to the acidity, duration, and proximal extent of reflux and the presence of erosive disease and cough reflex sensitivity in unselected patients (ie, including non-GOR causes) with chronic cough.

METHODS

Twenty-four hour ambulatory acoustic cough monitoring with simultaneous impedance/pH recording was carried out in 71 unselected patients with chronic cough, aged 51-64 years (47 female). In addition, all patients underwent cough reflex sensitivity testing to citric acid, and 66 patients underwent gastroscopy. Temporal associations between cough and reflux were expressed using the symptom association probability.

RESULTS

Seventy percent of patients exhibited temporal associations, with 48% having a positive symptom association probability (SAP(R-C)) for cough preceded by reflux (mainly distal), 56% a positive symptom association probability (SAP(C-R (2 min))) for reflux preceded by cough, and 32% both. Moreover, SAP(R-C) positive patients had a more sensitive cough reflex (P = .03) but similar esophageal reflux exposure and erosive disease, together with similar prevalence of extraesophageal causes of cough compared with SAP(R-C) negative patients. Reflux immediately following cough was rare.

CONCLUSIONS

Cough temporally associates with reflux irrespective of proposed diagnoses, may be self-perpetuating in some patients, and is likely to be driven by central processes.

Cigarette smoking and self-assessed upper airway health

Habitual smoking represents a chronic insult to the airway. However, the effects of smoking on upper airway health remains poorly described. Our objective was to examine the relationship between cigarette smoking and self-assessed upper airway health and evaluate dose-response relationships between exposure and complaints in a sample of 2,523 patients. Eligible subjects were adults referred to ENT specialist for evaluation of chronic nasal or sleep-related complaints. Thirteen specific symptoms and conditions, mainly related to the upper airway, were graded based on visual analog scales (VAS). Smokers, representing 33% of the sample, were more likely to report severe upper airway complaints compared to non-smokers (odds ratio 1.31-2.08) and exhibited significantly higher visual analog scale scores than non-smokers for 9 out of 13 outcome variables (p < 0.001-0.007). Further, significant associations were found between cigarette consumption and severity of complaints (p < 0.001-0.01), heavy smokers generally being more likely to exhibit high VAS scores than light smokers. In several cases smoking status and self-reported asthma/allergy had similar impact on subjective outcomes. Cigarette smoking was clearly associated with impaired upper airway health and seemed to be an important determinant in subjects seeking medical attention due to chronic nasal or sleep-related complaints. Both threshold and dose-response like relationships were evident between cigarette consumption and the outcome measures.

Validation of an ambulatory cough detection and counting application using voluntary cough under different conditions

Background

While cough is an important defence mechanism of the respiratory system, its chronic presence is bothersome and may indicate the presence of a serious disease. We hereby describe the validation process of a novel cough detection and counting technology (PulmoTrack-CC™, KarmelSonix, Haifa, Israel).

Methods

Tracheal and chest wall sounds, ambient sounds and chest motion were digitally recorded, using the PulmoTrack^® hardware, from healthy volunteers coughing voluntarily while (a) laying supine, (b) sitting, (c) sitting with strong ambient noise, (d) walking, and (e) climbing stairs, a total of 25 minutes per subject. The cough monitoring algorithm was applied to the recorded data to detect and count coughs.

The detection algorithm first searches for cough 'candidates' by identifying loud sounds with a cough pattern, followed by a secondary verification process based on detection of specific characteristics of cough. The recorded data were independently and blindly evaluated by trained experts who listened to the sounds and visually reviewed them on a sonogram display.

The validation process was based on two methods: (i) Referring to an expert consensus as gold standard, and comparing each cough detected by the algorithm to the expert marking, we marked True and False, positive and negative detections.These values were used to evaluate the specificity and sensitivity of the cough monitoring system. (ii) Counting the number of coughs in longer segments (t = 60 sec, n = 300) and plotting the cough count vs. the corresponding experts' count whereby the linear regression equation, the regression coefficient (R²) and the joint-distribution density Bland-Altman plots could be determined.

Results

Data were recorded from 12 volunteers undergoing the complete protocol. The overall Specificity for cough events was 94% and the Sensitivity was 96%, with similar values found for all conditions, except for the stair climbing stage where the Specificity was 87% with Sensitivity of 97%. The regression equation between the PulmoTrack-CC™ cough event counts and the Experts' determination was with R² of 0.94.

Discussion

This validation scheme provides an objective and quantitative assessment method of a cough counting algorithm in a range of realistic situations that simulate ambulatory monitoring of cough. The ability to detect voluntary coughs under acoustically challenging ambient conditions may represent a useful step towards a clinically applicable automatic cough detector.

Cough: a worldwide problem

Cough is a common and important respiratory symptom that can produce significant complications for patients and be a diagnostic challenge for physicians. An organized approach to evaluating cough begins with classifying it as acute, subacute, or chronic in duration. Acute cough lasting less than 3 weeks may indicate an acute underlying cardiorespiratory disorder but is most commonly caused by a self-limited viral upper respiratory tract infection (eg, common cold). Subacute cough lasting 3 to 8 weeks commonly has a postinfectious origin; among the causes, Bordetella pertussis infection should be included in the differential diagnosis. Chronic cough lasts longer than 8 weeks. When a patient is a nonsmoker, is not taking an angiotensin-converting enzyme inhibitor, and has a normal or near-normal chest radiograph, chronic cough is most commonly caused by upper airway cough syndrome, asthma, nonasthmatic eosinophilic bronchitis, or gastroesophageal reflux disease alone or in combination.

Future directions in treating cough

Cough is a common and troublesome symptom that can be difficult to treat. New therapeutic options that are safe and more effective than those currently available are needed. In this article, the authors offer opinion on future directions in the treatment of cough, with a particular emphasis on the clinical syndrome associated with cough reflex hypersensitivity. In addition, the article provides an overview of some of the diagnostic technologies and promising drug targets likely to emerge from current clinical and scientific endeavor.

Cough variant asthma and atopic cough

Chronic cough has been reported to be the fifth most common complaint seen by primary care physicians in the world, the third in Italy. Chronic cough in non-smoking, non-treated with ACE-inhibitor adults with normal chest radiogram could be a symptom of asthma and can be sub-classified into: cough-variant asthma, atopic cough, and eosinophilic bronchitis. This review discusses the differential diagnosis of these three disorders.

Activations of TRPA1 and P2X receptors are important in ROS-mediated stimulation of capsaicin-sensitive lung vagal afferents by cigarette smoke in rats

Capsaicin-sensitive lung vagal afferents (CSLVAs) are important in detecting pulmonary reactive oxygen species (ROS). We investigated the mechanisms underlying the stimulation of CSLVAs by inhaled cigarette smoke (CS) in 216 anesthetized rats. In spontaneously breathing rats, CS evoked a CSLVA-mediated reflex bradypnea that was prevented by N-acetyl-L-cysteine (NAC; an antioxidant), HC-030031 [a transient receptor potential ankyrin 1 (TRPA1) receptor antagonist], and iso-pyridoxalphosphate-6-azophenyl-2',5'-disulfonate (iso-PPADS; a P2X receptor antagonist). In paralyzed, artificially ventilated rats, CS evoked an increase in CSLVA fiber activity (DeltaFA) that was abolished by NAC and was attenuated by HC-030031, iso-PPADS, indomethacin (Indo; a cyclooxygenase inhibitor), and a combination of apyrase and adenosine deaminase (ADA) (ATP scavengers); the response to CS was reduced to 11.7+/-4.0%, 39.5+/-10.0%, 52.9+/-14.4%, 68.7+/-10.1%, and 47.2+/-12.9% of control, respectively. The suppressive effect on this afferent response was not improved by a combination of HC-030031 and Indo (DeltaFA=39.5+/-10.1% of control) compared with that induced by HC-030031 alone. In contrast, the suppressive effect was enhanced by a combination of HC-030031 and apyrase+ADA (DeltaFA=5.3+/-4.9% of control) or a combination of iso-PPADS and Indo (DeltaFA=23.3+/-7.7% of control) compared with that induced by HC-030031 alone or iso-PPADS alone. This afferent response was not altered by the vehicles for these drugs. These results suggest that activations of TRPA1 receptors by cyclooxygenase metabolites and P2X receptors by ATP are both necessary for the ROS-mediated stimulation of CSLVA fibers by CS in rats.

Perception of urge-to-cough and dyspnea in healthy smokers with decreased cough reflex sensitivity

Background

Although cigarette smoking has been implicated as an important risk factor for the development of respiratory symptoms, the perceptional aspects of two symptoms in smokers have not been fully elucidated. Therefore, we simultaneously evaluated the cough reflex sensitivity, the cognition of urge-to-cough and perception of dyspnea in both healthy smokers and non-smokers.

Methods

Fourteen male healthy never-smokers and 14 age-matched male healthy current-smokers were recruited via public postings. The cough reflex sensitivity and the urge-to-cough were evaluated by the inhalation of citric acid. The perception of dyspnea was evaluated by Borg scores during applications of external inspiratory resistive loads.

Results

The cough reflex threshold to citric acid, as expressed by the lowest concentration of citric acid that elicited two or more coughs (C₂) and the lowest concentration of citric acid that elicited five or more coughs (C₅) in smokers was significantly higher than in non-smokers. The urge-to-cough log-log slope in smokers was significantly milder than that of non-smokers. There were no significant differences in the urge-to-cough threshold between non-smokers and smokers. There were no significant differences in perceptions of dyspnea between non-smokers and smokers.

Conclusions

The study showed that decreased cough reflex sensitivity in healthy smokers was accompanied by a decreased cognition of urge-to-cough whereas it was not accompanied by the alternation of perception of dyspnea. Physicians should pay attention to the perceptual alterations of cough in smokers.

Associations of physical and mental health problems with chronic cough in a representative population cohort

BACKGROUND

Although chronic cough is a common problem in clinical practice, data on the prevalence and characteristics of cough in the general population are scarce. Our aim was to determine the prevalence of chronic cough that is not associated with diagnosed respiratory conditions and examine the impact on health status and psychological health, in a representative adult population cohort

METHODS

North West Adelaide Health Study (n stage 1 = 4060, stage 2 = 3160) is a representative population adult cohort. Clinical assessment included spirometry, anthropometry and skin tests. Questionnaires assessed demographics, lifestyle risk factors, quality of life, mental health and respiratory symptoms, doctor diagnosed conditions and medication use.

RESULTS

Of the 3355 people without identified lung disease at baseline, 18.2% reported chronic cough. In multiple logistic regression models, at follow-up, dry chronic cough without sputum production was significantly more common in males (OR 1.5, 95% CI 1.1, 1.9), current smokers (OR 4.9, 95% CI 3.4, 7.2), obesity (OR 1.9, 95% CI 1.3, 2.9), use of ACE inhibitors (OR 1.8, 95% CI 1.1, 2.9), severe mental health disturbance (OR 2.1, 95% CI 1.4, 3.1) and older age (40-59 years OR 1.7 95% CI 1.2, 2.4; > or = 60 years OR 2.1 95% CI 1.3, 3.5). Among non-smokers only, all cough was significantly more common in men, those with severe mental health disturbance and obesity.

CONCLUSIONS

Chronic cough is a major cause of morbidity. Attention to cough is indicated in patients with obesity, psychological symptoms or smokers. Inquiring about cough in those with mental health problems may identify reversible morbidity.

Does gastroesophageal reflux scintigraphy correlate with clinical findings in children with chronic cough?

OBJECTIVE

Gastroesophageal reflux (GER), a common problem during childhood, leads to chronic troublesome symptoms including chronic respiratory symptoms. Therefore, timely diagnostic work-up for GER is essential in children when GER is suspected. In this study, we aimed to establish whether scintigraphic parameters have clinical importance in investigating the reflux in children.

METHODS

A total of 72 children older than 7 years with chronic cough of unknown etiology were enrolled for this study. The scintigraphic procedure was performed by using technetium-99m tin colloid (37-74 MBq). Cough and GER scores were used for children who were positive for GER both before and after GER treatment.

RESULTS

Of 72 children, 65 children with a mean age of 10.3+/-2.3 (7-19) years had GER on gastroesophageal scintigraphy. Median reflux episode number was 7 (1-14). There was a significantly positive correlation between reflux episode number and cough (r = 0.446, P<0.001) and GER score (r = 0.432, P<0.001). The significant decrease was observed in cough (from 3.5+/-1.9 to 1.6+/-1.3) and GER scores (from 4.1+/-2.5 to 1.3+/-1.1) with GER treatment (P<0.001 for each).

CONCLUSION

Scintigraphy should be used for the detection of GER in children who present with chronic cough. Increasing episode number in gastroesophageal scintigraphy might be a predictor for reflux-related symptom severity.

The cough hypersensitivity syndrome: a novel paradigm for understanding cough

For many years patients with chronic cough have been investigated in an attempt to diagnose the cause of the cough. Here I suggest that the overwhelming majority of patients with chronic cough have a single diagnosis: cough hypersensitivity syndrome. This is demonstrated by the homogeneous nature of the clinical history and investigational results of patients attending cough clinics. The hypersensitivity facet of the syndrome is demonstrated by objective testing with capsaicin and other protussive agents. Within the cough hypersensitivity syndrome there are different phenotypes. Those patients with a predominantly Th2-type immune response will develop eosinophilic inflammation and either cough-variant asthma or eosinophilic bronchitis. Those with predominantly heartburn symptoms will have a phenotype that reflects GERD and cough. However, the similarities between the different phenotypes far outweigh differences in a unifying diagnosis of the cough hypersensitivity syndrome, providing a more rational understanding of chronic cough.

Cough reflex is additively potentiated by inputs from the laryngeal and tracheobronchial [corrected] receptors and enhanced by stimulation of the central respiratory neurons

The cough is an essential airway defense reflex. In this study we investigated the coordination of inputs from the laryngeal and tracheobronchial receptors in the cough reflex. In 15 beagle dogs (7-9 kg) lightly anesthetized with intravenous profobol (20-30 mg/kg/h), the cough response was elicited with mechanical stimulation of either the vocal chord or tracheal bifurcation. Simultaneous stimulation of both sites increased all the parameters of cough strength, that is, mean pleural pressure (P (pl)), mean expiratory flow, number of cough bouts, and cough duration, in comparison with stimulation of the sites individually. The increases in mean P (pl) and cough duration reached statistical significance (13.3 vs. 18.4 cmH(2)O and 13.3 vs. 18.2 s, respectively). When the anesthetic level became deeper, the prolongation of cough duration almost disappeared, but the augmentation of mean P (pl) was much less affected. During stimulation of the central respiratory neurons by intravenous dimorphoramine or acute hyperoxic hypercapnia, the cough strength increased significantly. We concluded that inputs from the laryngeal and tracheobonchial cough receptors acted in concert and potentiated the cough reflex. Furthermore, stimulation of the central respiratory neurons may increase the intensity of a cough response.

Prostanoid receptor antagonists: development strategies and therapeutic applications

Identification of the primary products of cyclo-oxygenase (COX)/prostaglandin synthase(s), which occurred between 1958 and 1976, was followed by a classification system for prostanoid receptors (DP, EP(1), EP(2) ...) based mainly on the pharmacological actions of natural and synthetic agonists and a few antagonists. The design of potent selective antagonists was rapid for certain prostanoid receptors (EP(1), TP), slow for others (FP, IP) and has yet to be achieved in certain cases (EP(2)). While some antagonists are structurally related to the natural agonist, most recent compounds are 'non-prostanoid' (often acyl-sulphonamides) and have emerged from high-throughput screening of compound libraries, made possible by the development of (functional) assays involving single recombinant prostanoid receptors. Selective antagonists have been crucial to defining the roles of PGD(2) (acting on DP(1) and DP(2) receptors) and PGE(2) (on EP(1) and EP(4) receptors) in various inflammatory conditions; there are clear opportunities for therapeutic intervention. The vast endeavour on TP (thromboxane) antagonists is considered in relation to their limited pharmaceutical success in the cardiovascular area. Correspondingly, the clinical utility of IP (prostacyclin) antagonists is assessed in relation to the cloud hanging over the long-term safety of selective COX-2 inhibitors. Aspirin apart, COX inhibitors broadly suppress all prostanoid pathways, while high selectivity has been a major goal in receptor antagonist development; more targeted therapy may require an intermediate position with defined antagonist selectivity profiles. This review is intended to provide overviews of each antagonist class (including prostamide antagonists), covering major development strategies and current and potential clinical usage.

The management of cough: a clinical year in review

As the number of published articles in the field of cough increases year on year, it is sometimes helpful to pause and review what might have passed us by. This "Clinical Year in Review" provides an opportunity to reflect on a number of important studies reported in the area of both adult and pediatric cough. It would be impossible to cover all the important published literature; therefore, this effort has been confined to selected topics published in the last 12 months with direct relevance to the clinical management, measurement, and treatment of cough. While this article reflects a personal commentary of the literature, it is hoped that it will contribute to improving "evidence-based" care for the many individuals burdened with a troublesome cough.

Rhinosinusitis, laryngopharyngeal reflux and cough: an ENT viewpoint

Chronic cough is a common presentation. Postnasal drip (PND) and gastro-oesophageal reflux are mostly implicated in the aetiology. Directly examining the larynx can often help to demonstrate laryngitis or inter-arytenoid oedema that is mostly attributed to reflux. Although "the syndrome of postnasal drip" is considered as a major cause for chronic cough, evidence of its existence is mostly difficult to elicit on examination. Furthermore, the majority of patients with "postnasal drip" seen in ENT outpatients do not complain of cough. Evidence does suggest there is a link between postnasal drip and cough. The fact that some patients present with cough in association with this syndrome and others do not is still not well understood.

Cough and viruses in airways disease: mechanisms

Acute cough is a major symptom of viral respiratory tract infection and causes excessive morbidity in human populations across the world. A wide variety of viruses play a role in the development of cough after acute infection and all of these manifest a similar clinical picture across different age groups. Despite the large disease burden surprisingly little is known about the mechanism of acute cough following viral infection. Both in vitro and in vivo experiments show that increased production of neuropeptides and leukotrienes mediate cough after viral infection, along with altered expression of neural receptors. Increased airway mucus production is also likely to play a significant role. This work is reviewed in this article.

Following the recent development of a mouse model for rhinovirus infection and the establishment of experimental models of rhinovirus challenge in human subjects with both asthma and COPD the field is expanding to translate in vitro research into clinical studies and hopefully eventually into clinical practice. Developing a clearer understanding of the mechanisms underlying virus induced cough may lead to more specific and effective therapies.

Postnasal drip and chronic cough: An open interventional study

BACKGROUND

The postnasal drip (PND) syndrome is often linked as a cause of chronic cough although this is disputed.

OBJECTIVES

We examined the effect of specific topical treatment of rhinosinusitis on cough in patients presenting with a chronic cough associated with a postnasal drip or 'nasal catarrh'.

METHODS

Patients presenting with a chronic cough and who complained of PND were enrolled and symptoms of PND and cough were assessed by questionnaire and by a capsaicin cough response. Rhinosinusitis was assessed by questionnaires, direct examination of the nose and by high-resolution computed tomography. In an open study, they were treated with fluticasone nasules, ipratropium bromide and azelastine nasal sprays for 28 days, after which they were re-assessed.

RESULTS

Eighteen out of 21 patients completed the study. All patients reported having the presence of mucus in the throat. Mean cough score improved post-treatment (p<0.05), but there was no significant change in capsaicin cough sensitivity or nasal catarrh questionnaire score. There was improvement in anterior nasal discharge symptom scores (p=0.005) and in endoscopic nasal scores post-treatment (p<0.01), with a tendency to improved PND scores.

CONCLUSION

In a pilot open 'real-life' study treatment targeted towards rhinosinusitis accompanying PND syndrome and chronic cough led to an improvement in cough. A randomised controlled study is now needed to confirm or refute these findings.

Expression of transforming growth factor-beta (TGF-beta) in chronic idiopathic cough

In patients with chronic idiopathic cough, there is a chronic inflammatory response together with evidence of airway wall remodelling and an increase in airway epithelial nerves expressing TRPV-1. We hypothesised that these changes could result from an increase in growth factors such as TGFbeta and neurotrophins. We recruited 13 patients with persistent non-asthmatic cough despite specific treatment of associated primary cause(s), or without associated primary cause, and 19 normal non-coughing volunteers without cough as controls, who underwent fiberoptic bronchoscopy with bronchoalveolar lavage (BAL) and bronchial biopsies. There was a significant increase in the levels of TGFbeta in BAL fluid, but not of nerve growth factor(NGF) and brain-derived nerve growth factor(BDNF) compared to normal volunteers. Levels of TFGbeta gene and protein expression were assessed in bronchial biopsies. mRNA expression for TGFbeta was observed in laser-captured airway smooth muscle and epithelial cells, and protein expression by immunohistochemistry was increased in ASM cells in chronic cough patients, associated with an increase in nuclear expression of the transcription factor, smad 2/3. Subbasement membrane thickness was significantly higher in cough patients compared to normal subjects and there was a positive correlation between TGF-beta levels in BAL and basement membrane thickening. TGFbeta in the airways may be important in the airway remodelling changes observed in chronic idiopathic cough patients, that could in turn lead to activation of the cough reflex.

Effect of the management of patients with chronic cough by pulmonologists and certified respiratory educators on quality of life: a randomized trial

BACKGROUND

The role of certified respiratory educators (CREs) is to educate, assess, and help to manage patients with asthma and COPD in Canada. This study was undertaken to see whether CREs could assist pulmonologists (MDs) in managing patients with chronic cough.

METHODS

An 8-week prospective, parallel design, randomized, controlled trial to determine whether CREs using a protocol-driven algorithmic approach could assist in the management of patients referred to a university tertiary care medical center for the assessment and treatment of chronic cough. Patients were randomly assigned to a CRE-led or MD study arm for the management of chronic cough. Patients were screened to exclude those patients whose cough was due to life-threatening conditions. The primary outcome was measured with the cough-specific quality-of-life questionnaire (CQLQ).

RESULTS

A total of 198 patients were randomized, and 8-week results were available on 151 patients (mean [+/- SD] age, 49.8 +/- 13.4 years; female gender, 70%; median cough duration, 16 months). At 8 weeks, total CQLQ scores improved in the CRE-led patients (score [+/- SD] range, 58.1 +/- 14.9 to 50.0 +/- 15.8; p = 0.0003). CQLQ scores improved in four of six domains but not in the physical or emotional domains. Improvements in CRE-led patients were similar to those in MD-managed patients (initial CQLQ score, p = 0.261 [CRE vs MD]; CQLQ score at 8 weeks, p = 0.42 [CRE vs MD]). In a composite analysis of both CRE and MD patient data, CQLQ scores improved in patients whose cough resolved (56.3 +/- 13.6 to 41.5 +/- 13.6; p < 0.0001), in those whose cough improved but did not disappear (60.9 +/- 14.2 to 50.5 +/- 13.9; p < 0.0001), but did not improve in those whose cough did not improve (58.1 +/- 13.3 to 58.6 +/- 12.7; difference not significant).

CONCLUSIONS

CREs can help to safely, economically, and effectively manage properly screened patients with chronic cough. The use of CREs may shorten wait times for specialist consultation for these patients.