Management of patients with chronic cough using a clinical protocol: a prospective observational study

Efficacy and Safety of Ojeok-San Plus Saengmaek-San for Gastroesophageal Reflux-Induced Chronic Cough: A Pilot, Randomized, Double-Blind, Placebo-Controlled Trial

Introduction: Gastroesophageal reflux-induced chronic cough (GERC) is one of the most common etiologies of chronic cough. Despite the growing prevalence and interest in GERC, no effective treatment is currently available. In our study, we used a combination of herbal medicines, Ojeok-san (OJS) plus Saengmaek-san (SMS), for the treatment of GERC. Methods: We conducted a pilot, randomized, placebo-controlled, parallel-arm, single-center clinical trial to assess the feasibility of our study protocol, as our study is the first herbal medicine trial for GERC. All enrolled participants were randomly assigned to either the intervention or placebo group in a 1:1 ratio and were administered trial drugs three times a day for 6 weeks, with an evaluation visit performed every 2 weeks for their efficacy and safety assessment until the follow-up visit (week 8). We evaluated the severity and frequency of cough, cough-specific quality of life, airway hypersensitivity, and reflux-related gastrointestinal symptoms, as well as pattern identification, to investigate the complex mechanisms of reflux cough syndrome. Results: A total of 30 participants were enrolled, and 25 completed the study at Kyung Hee University Korean Medicine Hospital from 26 December 2018 to 31 May 2021. OJS plus SMS significantly improved the cough diary score (CDS), cough visual analog scale, Korean version of the Leicester Cough Questionnaire, Hull Airway Reflux Questionnaire, and Gastrointestinal Symptom Rating Scale after the treatment compared to the baseline. Notably, OJS plus SMS showed significant efficacy in the daytime and total CDS compared with the placebo. Only one adverse event was observed during the trial, and no serious adverse events occurred. Additionally, we achieved successful results in feasibility outcomes by exceeding the ratio of 80%. Conclusion: We confirmed the feasibility of our trial design and demonstrated the potential of OJS plus SMS in relieving the severity of cough and GI symptoms in GERC patients with safe and successful feasibility results. We anticipate that our study results will be used as the basis for further large-scale, well-designed, confirmatory trials to evaluate the safety and efficacy of OJS plus SMS in GERC. Clinical Trial Registration: [https://cris.nih.go.kr], identifier WHO International Clinical Trials Registry Platform, Clinical Research Information Service [KCT0003115].

Cough detection using a non-contact microphone: A nocturnal cough study

An automatic non-contact cough detector designed especially for night audio recordings that can distinguish coughs from snores and other sounds is presented. Two different classifiers were implemented and tested: a Gaussian Mixture Model (GMM) and a Deep Neural Network (DNN). The detected coughs were analyzed and compared in different sleep stages and in terms of severity of Obstructive Sleep Apnea (OSA), along with age, Body Mass Index (BMI), and gender. The database was composed of nocturnal audio signals from 89 subjects recorded during a polysomnography study. The DNN-based system outperformed the GMM-based system, at 99.8% accuracy, with a sensitivity and specificity of 86.1% and 99.9%, respectively (Positive Predictive Value (PPV) of 78.4%). Cough events were significantly more frequent during wakefulness than in the sleep stages (p < 0.0001) and were significantly less frequent during deep sleep than in other sleep stages (p < 0.0001). A positive correlation was found between BMI and the number of nocturnal coughs (R = 0.232, p < 0.05), and between the number of nocturnal coughs and OSA severity in men (R = 0.278, p < 0.05). This non-contact cough detection system may thus be implemented to track the progression of respiratory illnesses and test reactions to different medications even at night when a contact sensor is uncomfortable or infeasible.

ACR Appropriateness Criteria® Chronic Cough

Chronic cough is defined by a duration lasting at least 8 weeks. The most common causes of chronic cough include smoking-related lung disease, upper airway cough syndrome, asthma, gastroesophageal reflux disease, and nonasthmatic eosinophilic bronchitis. The etiology of chronic cough in some patients may be difficult to localize to an isolated source and is often multifactorial. The complex pathophysiology, clinical presentation, and variable manifestations of chronic cough underscore the challenges faced by clinicians in the evaluation and management of these patients. Imaging plays a role in the initial evaluation, although there is a lack of high-quality evidence guiding which modalities are useful and at what point in time the clinical evaluation should be performed. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Cough symptom severity in patients with refractory or unexplained chronic cough: a systematic survey and conceptual framework

BACKGROUND

Cough severity represents an important subjective endpoint in assessing the effectiveness of therapies for patients with chronic cough. Although cough-specific quality of life questionnaires exist, a widely available cough severity instrument with established measurement properties remains unavailable.

AIMS

To identify and summarise the results of studies reporting on the experience of patients with chronic cough and, in the process, develop a conceptual framework to inform development of a patient-reported outcome measurement (PROM) addressing cough severity.

RESULTS

We identified 61 eligible studies reporting on patient experience with chronic cough. Studies provided 82 potential items, of which 43 proved unique and relevant to cough severity. The urge-to-cough sensation and the cough symptom itself represented broad domains of cough severity. Two subdomains under urge-to-cough included frequency (1 item) and intensity (1 item). Five subdomains under cough symptoms included control (2 items), frequency (6 items), bout duration (1 item), intensity (8 items), and associated features/sequelae (24 items).

CONCLUSIONS

Our systematic survey and conceptual framework identified items and domains of cough severity in patients with refractory or unexplained chronic cough. The results support item generation and content validity for a PROM assessing cough severity.

Cough: A Practical and Multifaceted Approach to Diagnosis and Management

Cough is a common symptom often confronted in the clinical setting. Time and resources attributed to cough place an undue burden on patients and the health care system. One characteristic of cough that likely contributes to this is the multifactorial nature of cough. Physicians are trained to find a single diagnosis to explain symptoms. With cough, if all factors contributing are not identified and treated together, the cough often remains unresolved. This article provides a practical approach to treatment and management of cough, emphasizing causes and potentiators.

Surgical Treatment of Extraesophageal Manifestations of Gastroesophageal Reflux Disease

OBJECTIVE

To review the current literature on the role of antireflux surgery (ARS) for the treatment of extraesophageal manifestations of GERD. The extraesophageal manifestations of gastroesophageal reflux disease (GERD) include chronic cough, laryngopharyngeal reflux, and asthma. They are responsible for significant morbidity in affected patients and a high economic burden on healthcare resources. We recently published a larger review on the symptoms, diagnosis, medical, and surgical treatment of the extraesophageal manifestations of GERD. Through our investigation, we found that the role of ARS for respiratory symptoms was unclear. Hence, we resorted through the data of our previous meta-analysis to compile a comprehensive and focused review on the role of ARS for respiratory symptoms.

METHODS

Using the archive of our previous meta-analysis, we selected studies extracted from the MEDLINE, Cochran, PubMed, Google Scholar, and Embase databases pertaining to the surgical treatment of extraesophageal manifestations of reflux (cough laryngopharyngeal reflux, and asthma). We applied a similar reporting methodology as was used in our previous manuscript and then hand searched the bibliographies of included studies yielding a total of 27 articles for review. We graded the level of evidence and classified recommendations by size of treatment effect per the American Heart Association Task Force on Practice Guidelines.

RESULTS

Observational data indicated that syndromes of chronic cough, laryngopharyngeal reflux and asthma might improve after antireflux surgery only in highly selected patients-likely those with non-acid reflux-while those patients with objective markers of asthma severity do not. Because of the varied methods of diagnosis and surgical technique, non-comparative observational data may be unreliable. Additionally, our search found no randomized controlled trials (RCTs) comparing antireflux surgery to medical therapy in the treatment of cough or laryngopharyngeal reflux. One RCT compared medical treatment to antireflux surgery in patients with asthma, but medical treatment included high-dose H₂ blockers instead of PPIs.

CONCLUSIONS

Extraesophageal manifestations of GERD are common, costly, and difficult to treat. ARS might be effective in highly selected patients, especially in those whose extraesophageal manifestations are caused by non-acid reflux. The available data to date are generally of poor quality or outdated. Well-designed randomized controlled trials or large-scale observational cohort studies are urgently needed.

Efficacy of sequential three-step empirical therapy for chronic cough

Background:

Empirical three-step therapy has been proved in just one hospital. This study aimed to demonstrate applicability of the sequential empirical three-step therapy for chronic cough in different clinical settings.

Methods:

Sequential empirical three-step therapy was given to patients with chronic cough in one tertiary and three secondary care respiratory clinics. Recruiters were initially treated with methoxyphenamine compound as the first-step therapy, followed by corticosteroids as the second-step therapy and the combination of a proton-pump inhibitor and a prokinetic agent as the third-step therapy. The efficacy of the therapy was verified according to the changes in cough symptom score between pre- and post-treatment, and compared among the different clinics.

Results:

In total 155 patients in one tertiary clinic and 193 patients in secondary care clinics were recruited. The total dropout ratio is significantly higher in the secondary care clinics than that in the tertiary clinic (9.3% versus 3.2%, p = 0.023). The therapeutic success rate for cough was 38.7% at first-step therapy, 32.3% at second-step therapy and 20.0% at third-step therapy in the tertiary clinic, and comparable to corresponding 49.7%, 31.1% and 4.1% in secondary care clinics. Furthermore, the overall cough resolution rate was not significantly different (91.0% versus 85.0%, p = 0.091). However, the efficacy of the third-step therapy is much higher (20.0% versus 4.1%, p = 0.001) in the tertiary clinic than in the secondary care clinics.

Conclusions:

Sequential empirical three-step therapy is universally efficacious and useful for management of chronic cough in different clinical settings.

Diagnosis and Treatment of the Extraesophageal Manifestations of Gastroesophageal Reflux Disease

OBJECTIVE

To review the clinical presentation, diagnosis, and treatment options available for management of extraesophageal manifestations of gastroesophageal reflux disease (GERD) and to compare the most recent technological advances to the existing guidelines.

SUMMARY BACKGROUND DATA

Extraesophageal manifestations of GERD include cough, laryngopharyngeal reflux (LPR), and asthma. Recent advances in diagnostic modalities may have outpaced the existing diagnostic and therapeutic clinical guidelines.

METHODS

We searched the MEDLINE, Cochrane, and Embase databases for articles pertaining to the presentation, diagnosis, and treatment of extraesophageal manifestations of reflux, specifically cough due to reflux, LPR, and asthma due to reflux. Search terms applied to 3 thematic topics: diagnosis, medical treatment, and surgical treatment. We had searched the bibliographies of included studies, yielding a total of 271 articles for full review. We graded the level of evidence and classified recommendations by size of treatment effect, according to the guidelines from the American Heart Association Task Force on Practice Guidelines.

RESULTS

One hundred twenty-eight articles met criteria for analysis. Our findings show that the diagnosis of cough, LPR, or asthma due to gastroesophageal reflux is difficult, as no criterion standard test exits. Also, patients often present without heartburn or regurgitation typical of GERD. Combined multichannel intraluminal impedance, the pH (MII-pH) monitoring system, and the symptom association probability (SAP) test might distinguish extraesophageal manifestations of reflux from idiopathic chronic cough, laryngitis due to other causes, and atopic asthma. In addition, extraesophageal manifestations of reflux are most effectively diagnosed with a stepwise approach incorporating empiric treatment and antisecretory therapy, combined MII-pH monitoring, and surgical intervention in few selected cases.

CONCLUSIONS

Recent studies demonstrate the potential diagnostic role of MII-pH monitoring. Surgical intervention provides resolution of extraesophageal symptoms less reliably than typical symptoms when the patient has GERD.

Chronic Cough Due to Gastroesophageal Reflux in Adults: CHEST Guideline and Expert Panel Report

BACKGROUND

We updated the 2006 ACCP clinical practice guidelines for management of reflux-cough syndrome.

METHODS

Two population, intervention, comparison, outcome (PICO) questions were addressed by systematic review: (1) Can therapy for gastroesophageal reflux improve or eliminate cough in adults with chronic and persistently troublesome cough? and (2) Are there minimal clinical criteria to guide practice in determining that chronic cough is likely to respond to therapy for gastroesophageal reflux?

RESULTS

We found no high-quality studies pertinent to either question. From available randomized controlled trials (RCTs) addressing question #1, we concluded that (1) there was a strong placebo effect for cough improvement; (2) studies including diet modification and weight loss had better cough outcomes; (3) although lifestyle modifications and weight reduction may be beneficial in suspected reflux-cough syndrome, proton pump inhibitors (PPIs) demonstrated no benefit when used in isolation; and (4) because of potential carryover effect, crossover studies using PPIs should be avoided. For question #2, we concluded from the available observational trials that (1) an algorithmic approach to management resolved chronic cough in 82% to 100% of instances; (2) cough variant asthma and upper airway cough syndrome (UACS) (previously referred to as postnasal drip syndrome) from rhinosinus conditions were the most commonly reported causes; and (3) the reported prevalence of reflux-cough syndrome varied widely.

CONCLUSIONS

The panelists (1) endorsed the use of a diagnostic/therapeutic algorithm addressing causes of common cough, including symptomatic reflux; (2) advised that although lifestyle modifications and weight reduction may be beneficial in suspected reflux-cough syndrome, PPIs demonstrated no benefit when used in isolation; and (3) suggested that physiological testing be reserved for refractory patients being considered for antireflux surgery or for those in whom there is strong clinical suspicion warranting diagnostic testing.

Chronic cough and a normal chest X-ray - a simple systematic approach to exclude common causes before referral to secondary care: a retrospective cohort study

Chronic cough is common in the community and can cause significant morbidity. It is not clear how closely treatment guidelines are used in general practice, or how often specialist referral is indicated. We aimed to assess the management of chronic cough in primary care before referral to a cough clinic, and to assess the outcome of managing chronic cough with an approach of simple investigation and empirical treatment trials. Data were extracted from the records of all patients attending a district general hospital respiratory clinic over a two-year period with isolated chronic cough lasting ⩾8 weeks. The clinic assessed symptoms with a cough-severity visual analogue scale and the Leicester Cough Questionnaire. Among 266 patients, the most frequent diagnoses were asthma (29%), gastro-oesophageal reflux (22%) and angiotensin-converting enzyme inhibitor use (14%). In all, 12% had unexplained chronic cough. Common diagnoses had often not been excluded in primary care: only 21% had undergone spirometry, 86% had undergone chest radiography and attempts to exclude asthma with corticosteroids had been made only in 39%. In the clinic few investigations were conducted that were not available in primary care. Substantial improvements in symptoms occurred with a median (interquartile range) total of 2 (2–3) clinic visits. We estimated that 87% of patients could have been managed solely in primary care; we did not identify distinguishing characteristics among this group. Most cases of chronic cough referred to secondary care could be managed with a simple and systematic approach, which is potentially transferrable to a community setting.

Assessment of Intervention Fidelity and Recommendations for Researchers Conducting Studies on the Diagnosis and Treatment of Chronic Cough in the Adult: CHEST Guideline and Expert Panel Report

BACKGROUND

Successful management of chronic cough has varied in the primary research studies in the reported literature. One of the potential reasons relates to a lack of intervention fidelity to the core elements of the diagnostic and/or therapeutic interventions that were meant to be used by the investigators.

METHODS

We conducted a systematic review to summarize the evidence supporting intervention fidelity as an important methodologic consideration in assessing the effectiveness of clinical practice guidelines used for the diagnosis and management of chronic cough. We developed and used a tool to assess for five areas of intervention fidelity. Medline (PubMed), Scopus, and the Cochrane Database of Systematic Reviews were searched from January 1998 to May 2014. Guideline recommendations and suggestions for those conducting research using guidelines or protocols to diagnose and manage chronic cough in the adult were developed and voted upon using CHEST Organization methodology.

RESULTS

A total of 23 studies (17 uncontrolled prospective observational, two randomized controlled, and four retrospective observational) met our inclusion criteria. These articles included 3,636 patients. Data could not be pooled for meta-analysis because of heterogeneity. Findings related to the five areas of intervention fidelity included three areas primarily related to the provider and two primarily related to the patients. In the area of study design, 11 of 23 studies appeared to be underpinned by a single guideline/protocol; for training of providers, two of 23 studies reported training, and zero of 23 reported the use of an intervention manual; and for the area of delivery of treatment, when assessing the treatment of gastroesophageal reflux disease, three of 23 studies appeared consistent with the most recent guideline/protocol referenced by the authors. For receipt of treatment, zero of 23 studies mentioned measuring concordance of patient-interventionist understanding of the treatment recommended, and zero of 23 mentioned measuring enactment of treatment, with three of 23 measuring side effects and two of 23 measuring adherence. The overall average intervention fidelity score for all 23 studies was poor (20.74 out of 48).

CONCLUSIONS

Only low-quality evidence supports that intervention fidelity strategies were used when conducting primary research in diagnosing and managing chronic cough in adults. This supports the contention that some of the variability in the reporting of patients with unexplained or unresolved chronic cough may be due to lack of intervention fidelity. By following the recommendations and suggestions in this article, researchers will likely be better able to incorporate strategies to address intervention fidelity, thereby strengthening the validity and generalizability of their results that provide the basis for the development of trustworthy guidelines.

Therapeutic-diagnostic Evaluation of Chronic Cough Amongst Adults: Causes, Symptoms and Management at the Primary Care Level, Malaysia

Background:

Patients presenting with chronic cough pose a common diagnostic dilemma during routine consultations at public primary care clinics in Malaysia. To date, there has been little attempt at designing a standardized model or algorithm to facilitate an accurate diagnosis of chronic cough. This study proposes a clinical method to detect the causes of chronic cough in a primary care setting in Malaysia.

Materials and Methods:

A total of 117 patients aged above 18 at an urban primary care clinic were tracked over a span of 5 months to diagnose the cause of chronic cough. A therapeutic-diagnostic method was employed to help identify the causes of chronic cough. Subsequently, the demographic details of patients, the prevalence of the different causes of chronic cough and the relationship between history and diagnosis were analyzed statistically.

Results:

Chronic cough had a slightly higher male preponderance (51.3% vs. 48.7%). Patients within the ‘above 60’ age category had the highest frequency of chronic cough. The most common cause of chronic cough was post-infectious cough (n = 42, 35.9%), followed closely by angiotensin-converting enzyme-inhibitor related cough (n = 14, 12%). Majority of patients had the symptom of phlegm production (n = 41, 54%). 33 patients (29.2%) had recent upper respiratory tract infection (<2 weeks ago) prior to the diagnosis of chronic cough. There were poor association between symptoms and the various entities comprising chronic cough. The exceptions were the following associations: (1) Bronchial asthma and itchiness of throat (P = 0021), (2) gastroesophageal reflux disease and heartburn (P < 0.001), (3) upper airway cough syndrome and running nose (P = 0.016) and (4) pulmonary tuberculosis and absence of weight loss (P = 0.004).

Conclusion:

This study demonstrates that the effectiveness of a therapeutic-diagnostic technique in the diagnosis of chronic cough. Consistent with previous studies, there was poor association between most symptoms and the causes of chronic cough. A study involving a larger primary care population is required to confirm the findings found in this analysis.

Mechanisms of cough

PURPOSE OF REVIEW

To review recent developments in the mechanisms of chronic cough.

RECENT FINDINGS

Although cough prevalence is similar across the world, there are significant regional differences in the diseases associated with cough. This may represent regional differences in diet, environmental exposure, and diagnostic assessment and labelling. Cough can be reliably measured using several validated questionnaires and objective tools that monitor cough frequency and cough reflex sensitivity. Cough with eosinophilic bronchitis responds to anti-inflammatory therapy with corticosteroids and montelukast. The absence of airway hyperresponsiveness may be because of the release of a bronchoprotective mediator, prostaglandin E2. Cough with neutrophilic bronchitis is associated with rhinitis and gastroesophageal reflux disease. Laryngeal hypersensitivity (LHS) is an important new concept that explains cough mechanisms, identifies potentially new pharmacotherapies that target neural pathways and also transient receptor channels, and demonstrates how behavioural therapies can be effective in refractory cough. The concept also explains symptoms in a variety of related syndromes such as vocal cord dysfunction.

SUMMARY

New insights into cough mechanisms that focus on LHS help explain cough symptoms and the place of effective therapies including speech pathology intervention and neuromodulators.

Chronic cough: a gastroenterology perspective

PURPOSE OF REVIEW

The purpose of this review is to highlight recent work and provide recommendations on the approach for diagnosis and management of chronic cough in a gastroenterology clinic.

RECENT FINDINGS

Chronic cough is a burdensome symptom affecting a large number of patients and contributes significant cost to the healthcare system. Recent work has shown that select patients may benefit from acid-suppressive therapy and even surgery when there is true pathologic evidence of reflux disease with cough. However, judicious use and proper interpretation of diagnostic testing for gastroesophageal reflux in the setting of cough is important to avoid unnecessary or inappropriate therapy.

SUMMARY

Chronic cough remains a vexing problem for many physicians, including gastroenterologists. It is important that physicians approach refractory cough in a multidisciplinary manner. Future research is needed to better understand the likely central hypersensitivity response mediating reflux-related cough and potential alternative approaches to therapy.

On the definition of chronic cough and current treatment pathways: an international qualitative study

BACKGROUND

The pathogenesis of chronic cough is not well understood and treatment options are limited. In this study we sought to explore the current understanding and management of chronic cough across an international group of specialists.

METHODS

This was an international study of cross sectional qualitative design. In depth interviews were carried out with "Respiratory Specialists" experienced in treating treating Chronic Obstructive Pulmonary Disease (COPD), idiopathic pulmonary fibrosis (IPF), idiopathic chronic cough (ICC) and/or lung cancer patients and with "Disease Experts" in the field of Chronic Cough. Participants in the study were recruited from the USA, UK, Germany, Ireland, Australia and Japan. Interviews with specialists were held at research facilities and with DEs over the telephone. These were preceded by the specialists completing case records of patients recently seen. All interviews were conducted by native speaking trained moderators using a semi-structured interview guide script. This was designed to elicit the definition of chronic cough, explore the unmet needs for each disease state, define therapy goals, identify patient phenotypes and give an overview of the treatment pathway.

RESULTS

76 specialists and 10 experts took part in the study. Over two thirds (70%) of respondents defined chronic cough as "cough lasting more than 8/12 weeks" (range 2 weeks to 2 years). Physicians emphasised three interdependent aspects of clinical assessment: impact on quality of life, type of cough (productive versus non-productive) and the underlying pathology. Specialists emphasised treating the underlying cause rather than the cough, this being most prominent in Japan. Experts as a group focussed on chronic cough independently. Evaluation of the respiratory system, GI tract and upper airway (ENT) for establishing an underlying cause was recommended. Type of cough (productive vs non-productive) and impact on quality of life influenced treatment initiation. 33% of patients with ICC were prescribed anti-tussives. With associated diagnoses of COPD, IPF or lung cancer the emphasis was on treating the underlying condition. Alternatives to pharmacological treatments were frequently considered.

CONCLUSION

There is significant international variation in our understanding and management of chronic cough. Further work is required to bring forth clear guidance and effective medicines for these patients.