An update on measurement and monitoring of cough: what are the important study endpoints?

[New medical technologies in cough therapy: results of a double-blind randomized placebo-controlled multicenter clinical trial]

AIM

To study the efficacy and safety of Eladis® in comparison with placebo in patients with non-productive cough.

MATERIALS AND METHODS

A phase III clinical trial enrolled 250 patients aged 18-65 years with acute respiratory viral infection with upper respiratory tract involvement or acute bronchitis. Patients were randomized into 2 groups of 125 subjects: group 1 received Eladis® (40 mg tablets), group 2 received a matching placebo. The patients received the study drugs 1 tablet BID for 7-14 days. After the treatment, patients were followed up (day 7±2) to assess the effect of therapy on the frequency of coughing attacks, the frequency and severity of daytime and nocturnal cough, the severity of cough, the duration of clinical cough cure, and the effect on the severity of the main acute respiratory viral infection symptoms.

RESULTS AND CONCLUSION

The results of the study demonstrate the overall efficacy and statistically significant superiority of Eladis® over placebo: there were significant differences between the study groups in the proportion of patients who decreased the coughing attack frequency by ≥50% by day 5 (p<0.0001). In addition, the clinical cure of cough in the Eladis® group occurred 2 days earlier: the median time was 6 days, vs 8 days in placebo group. There was a decrease in the frequency of cough attacks and a decrease in its severity by more than 3.5 points by day 5 of treatment. All the effects were associated with high safety of the drug.

Persistent cough after pulmonary resection: Minor issue, major hurdle

Background

Persistent cough is one of the most common complications following pulmonary resection, that impairs patients' quality of life and prolongs recovery time. However, a comprehensive review of persistent cough after pulmonary resection (CAP) has not been performed.

Methods

A literature search of PubMed/MEDLINE, Web of Science, and Embase database was conducted for persistent-CAP up to June 2023. Subsequent qualitative systematic review focused on definition, risk factors, prevention, and treatment of persistent-CAP.

Results

Persistent-CAP stands as a prevalent postoperative complication subsequent to pulmonary resection procedures. with an incidence of 24.4-55.0 %. Although persistent-CAP has a minor impact on survival, this condition is of critical importance because it presents a major hurdle in recovery after surgery. In this review, we proposed a systemic definition for persistent-CAP based on available evidence and our own data. Several assessment tools used to assess severity of persistent-CAP are also introduced. Risk factors associated with persistent-CAP are explored, including surgical approaches, resection extent, surgical site, lymph node dissection, postoperative gastroesophageal acid reflux, tracheal intubation anesthesia, preoperative comorbidity, and sex among others. Surgical and anesthesia preventions targeting risk factors to prevent persistent-CAP are elaborated. A number of studies have shown that a multidisciplinary approach can effectively relieve persistent-CAP.

Conclusions

Although the mechanisms underlying persistent-CAP are still unclear, existing studies demonstrated that persistent-CAP is related to surgical and anesthesia factors. Therefore, in the future, prevention and treatment should be developed based on risk factors to overcome the hurdle of persistent-CAP.

Identifying unique spectral fingerprints in cough sounds for diagnosing respiratory ailments

Coughing, a prevalent symptom of many illnesses, including COVID-19, has led researchers to explore the potential of cough sound signals for cost-effective disease diagnosis. Traditional diagnostic methods, which can be expensive and require specialized personnel, contrast with the more accessible smartphone analysis of coughs. Typically, coughs are classified as wet or dry based on their phase duration. However, the utilization of acoustic analysis for diagnostic purposes is not widespread. Our study examined cough sounds from 1183 COVID-19-positive patients and compared them with 341 non-COVID-19 cough samples, as well as analyzing distinctions between pneumonia and asthma-related coughs. After rigorous optimization across frequency ranges, specific frequency bands were found to correlate with each respiratory ailment. Statistical separability tests validated these findings, and machine learning algorithms, including linear discriminant analysis and k-nearest neighbors classifiers, were employed to confirm the presence of distinct frequency bands in the cough signal power spectrum associated with particular diseases. The identification of these acoustic signatures in cough sounds holds the potential to transform the classification and diagnosis of respiratory diseases, offering an affordable and widely accessible healthcare tool.

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.

Methods of Cough Assessment and Objectivization

Cough is one of the most important airway defensive reflexes aimed at removing foreign particles or endogenously produced materials from the airways and provides protection against aspiration. Generally considered, cough is a vital physiological defensive mechanism for lung health. However, in case of cough dysregulation this reflex can become pathological and leads to an adverse influence on daily life. Therefore, it is necessary to effectively evaluate the severity of cough for its diagnosis and treatment. There are subjective and objective methods for assessing cough. These methods should help describe the heterogeneity of cough phenotypes and may establish better treatment by monitoring response to nonpharmacological or pharmacological therapies. It is important to keep in mind that the clinical assessment of cough should include both tools that measure the amount and severity of the cough. The importance of a combined subjective and objective evaluation for a comprehensive assessment of cough has been advocated in the guidelines of the European Respiratory Society on cough evaluation. This review article provides an overview of subjective and objective methods for assessing and monitoring cough in children and adults comparing to animal models. Key words Cough frequency; Cough intensity; Cough reflex sensitivity; Cough monitors; Cough assessment.

A smartphone-based application for cough counting in patients with acute asthma exacerbation

BACKGROUND

While tools exist for objective cough counting in clinical studies, there is no available tool for objective cough measurement in clinical practice. An artificial intelligence (AI)-based cough count system was recently developed that quantifies cough sounds collected through a smartphone application. In this prospective study, this AI-based cough algorithm was applied among real-world patients with an acute exacerbation of asthma.

METHODS

Patients with an acute asthma exacerbation recorded their cough sounds for 7 days (2 consecutive hours during awake time and 5 consecutive hours during sleep) using CoughyTM smartphone application. During the study period, subjects received systemic corticosteroids and bronchodilator to control asthma. Coughs collected by application were counted by both the AI algorithm and two human experts. Subjects also provided self-measured peak expiratory flow rate (PEFR) and completed other outcome assessments [e.g., cough symptom visual analogue scale (CS-VAS), awake frequency, salbutamol use] to investigate the correlation between cough and other parameters.

RESULTS

A total of 1,417.6 h of cough recordings were obtained from 24 asthmatics (median age =39 years). Cough counts by AI were strongly correlated with manual cough counts during sleep time (rho =0.908, P<0.001) and awake time (rho =0.847, P<0.001). Sleep time cough counts were moderately to strongly correlated with CS-VAS (rho =0.339, P<0.001), the frequency of waking up (rho =0.462, P<0.001), and salbutamol use at night (rho =0.243, P<0.001). Weak-to-moderate correlations were found between awake time cough counts and CS-VAS (rho =0.313, P<0.001), the degree of activity limitation (rho =0.169, P=0.005), and salbutamol use at awake time (rho =0.276, P<0.001). Neither awake time nor sleep time cough counts were significantly correlated with PEFR.

CONCLUSIONS

The strong correlation between cough counts using the AI-based algorithm and human experts, and other indicators of patient health status provides evidence of the validity of this AI algorithm for use in asthma patients experiencing an acute exacerbation. Study findings suggest that CoughyTM could be a novel solution for objectively monitoring cough in a clinical setting.

The P2X3 receptor antagonist filapixant in patients with refractory chronic cough: a randomized controlled trial

BACKGROUND

P2X3 receptor antagonists seem to have a promising potential for treating patients with refractory chronic cough. In this double-blind, randomized, placebo-controlled study, we investigated the efficacy, safety, and tolerability of the novel selective P2X3 receptor antagonist filapixant (BAY1902607) in patients with refractory chronic cough.

METHODS

Following a crossover design, 23 patients with refractory chronic cough (age: 60.4 ± 9.1 years) received ascending doses of filapixant in one period (20, 80, 150, and 250 mg, twice daily, 4-days-on/3-days-off) and placebo in the other. The primary efficacy endpoint was the 24-h cough frequency on Day 4 of each dosing step. Further, subjective cough severity and health-related quality of life were assessed.

RESULTS

Filapixant at doses ≥ 80 mg significantly reduced cough frequency and severity and improved cough health-related quality of life. Reductions in 24-h cough frequency over placebo ranged from 17% (80 mg dose) to 37% (250 mg dose), reductions over baseline from 23% (80 mg) to 41% (250 mg) (placebo: 6%). Reductions in cough severity ratings on a 100-mm visual analog scale ranged from 8 mm (80 mg) to 21 mm (250 mg). No serious or severe adverse events or adverse events leading to discontinuation of treatment were reported. Taste-related adverse events occurred in 4%, 13%, 43%, and 57% of patients treated with filapixant 20, 80, 150, and 250 mg, respectively, and in 12% treated with placebo.

CONCLUSIONS

Filapixant proved to be efficacious, safe, and-apart from the occurrence of taste disturbances, especially at higher dosages-well tolerated during the short therapeutic intervention. Clinical trial registration EudraCT, eudract.ema.europa.eu, 2018-000129-29; ClinicalTrials.gov, NCT03535168.

Efficacy and tolerability of zinc acetate for treatment of chronic refractory cough: pilot randomised futility trial

Background

Cough is the most reported symptom in the United States, with chronic refractory cough representing significant morbidity to patients. Zinc acetate may have beneficial effects in the cough reflex pathway. We sought to assess the safety and efficacy of zinc acetate in the management of chronic refractory cough.

Study design and methods

This was a randomised, placebo-controlled, parallel-design pilot trial of individuals with chronic refractory cough. The effects of 6 weeks of zinc acetate versus placebo on quality of life and symptoms as measured by the Cough Quality-of-Life Questionnaire (CQLQ), Leicester Cough Questionnaire (LCQ), cough visual analogue score (C-VAS) and Global Assessment of Change in Cough (GACC) scores were evaluated. A futility analysis plan with a one-sided 80% confidence interval was used to compare treatment effect to published minimum clinically important differences (MCID) for each outcome.

Results

34 participants, 17 in each group, were enrolled and randomised. Participants were primarily white females with moderate-severe cough. Participants assigned to zinc acetate had a significant increase in serum zinc levels after 6 weeks, while those assigned to placebo did not. Both groups showed improvement in CQLQ, LCQ, C-VAS and GACC scores, but the treatment effects of zinc acetate versus placebo were small with confidence intervals that did not include the MCIDs.

Interpretation

We observed no benefit of zinc therapy over placebo on cough symptoms or quality of life and conclude that larger trials of zinc for chronic cough are not warranted.

Evaluation of noscapine-licorice combination effects on cough relieving in COVID-19 outpatients: A randomized controlled trial

Background: As February 2023, SARS-CoV-2 is still infecting people and children worldwide. Cough and dyspnea are annoying symptoms almost present in a large proportion of COVID-19 outpatients, and the duration of these symptoms might be long enough to affect the patients' quality of life. Studies have shown positive effects for noscapine plus licorice in the previous COVID-19 trials. This study aimed to assess the effects of the combination of noscapine and licorice-for relieving cough in outpatients with COVID-19. Methods: This randomized controlled trial was conducted on 124 patients at the Dr. Masih Daneshvari Hospital. Participants over 18 years of age with confirmed COVID-19 and cough were allowed to enter the study if the onset of symptoms was less than 5 days. The primary outcome was to assess the response to treatment over 5 days using the visual analogue scale. Secondary outcomes included the assessment of cough severity after 5 days using Cough Symptom Score, as well as the cough-related quality of life and dyspnea relieving. Patients in the noscapine plus licorice group received Noscough^® syrup 20 mL every 6 h for 5 days. The control group received diphenhydramine elixir 7 mL every 8 h. Results: By day five, 53 (85.48%) patients in the Noscough^® group and 49 (79.03%) patients in the diphenhydramine group had response to treatment. This difference was not statistically significant (p-value = 0.34). The presence of dyspnea was significantly lower in the Noscough^® group versus diphenhydramine at day five (1.61% in the Noscough^® group vs. 12.9% in the diphenhydramine group; p-value = 0.03). The cough-related quality of life and severity also significantly favored Noscough^® syrup (p-values <0.001). Conclusion: Noscapine plus licorice syrup was slightly superior to diphenhydramine in relieving cough symptoms and dyspnea in the COVID-19 outpatients. The severity of cough and cough-related quality of life were also significantly better in the noscapine plus licorice syrup. Noscapine plus licorice may be a valuable treatment in relieving cough in COVID-19 outpatients.

Chronic cough-the limitation and advances in assessment techniques

Accurate and consistent assessments of cough are essential to advance the understanding of the mechanisms of cough and individualised the management of patients. Considerable progress has been made in this work. Here we reviewed the currently available tools for subjectively and objectively measuring both cough sensitivity and severity. We also provided some opinions on the new techniques and future directions. The simple and practical Visual Analogue Scale (VAS), the Leicester Cough Questionnaire (LCQ), and the Cough Specific Quality of Life Questionnaire (CQLQ) are the most widely used self-reported questionnaires for evaluating and quantifying cough severity. The Hull Airway Reflux Questionnaire (HARQ) is a tool to elucidate the constellation of symptoms underlying the diagnosis of chronic cough. Chemical excitation tests are widely used to explore the pathophysiological mechanisms of the cough reflex, such as capsaicin, citric acid and adenosine triphosphate (ATP) challenge test. Cough frequency is an ideal primary endpoint for clinical research, but the application of cough counters has been limited in clinical practice by the high cost and reliance on aural validation. The ongoing development of cough detection technology for smartphone apps and wearable devices will hopefully simplify cough counting, thus transitioning it from niche research to a widely available clinical application.

The Effect of Softening of Endotracheal Tubes on the Decrement of Postoperative Hoarseness and Sore Throat

Background

Hoarseness, cough, and sore throat are the most prevalent complications after removing patients' endotracheal tube and general anesthesia. Various methods have been proposed to reduce these complications after intubation.

Objectives

The present study aimed to assess the effect of softening the endotracheal tube with normal warm saline on reducing post-intubation complications such as sore throat and hoarseness.

Methods

This double-blind, randomized controlled trial was performed on patients undergoing general anesthesia at Rasoul Akram and Firoozgar hospitals in Tehran, Iran. In the present study, 58 patients were randomly divided into 2 groups of 29 patients. All patients underwent the same premedication with fentanyl and lidocaine. Anesthesia was induced with propofol and atracurium. Three to 5 minutes after atracurium injection, the laryngoscopy test was performed. Randomly, some patients were intubated with a thermally softened endotracheal tube, and some were intubated with a normal tube. At the end of the operation, when the spontaneous breathing was adequate, and the patients could carry out oral instructions, the endotracheal tube was removed immediately after suctioning. All patients were evaluated for sore throat and hoarseness before discharge from recovery and 24 hours after surgery. The obtained data were analyzed using SPSS software package version 25.

Results

The mean incidence of sore throat in recovery in the intervention group (20.7%) decreased compared to the control group (75.8%). Moreover, the mean incidence of hoarseness in the intervention group (17.2%) decreased in comparison to the control group (41.4%, P < 0.029). Based on the data of our study, we observed that 24 hours after surgery, the mean incidence of sore throat among the patients of the intervention group was significantly lower compared to the control group, where patients in the intervention group did not feel any sore throat (P < 0.002). We also observed that 24 hours after surgery, the amount of hoarseness in the intervention group (3.4%) also decreased compared to the control group (24.1%, P < 0.022).

Conclusions

Based on the results, it can be concluded that thermal softening of the endotracheal tubes with normal warm saline before intubation could be significantly effective in decrement of sore throat and hoarseness during recovery and 24 hours after surgery.

Effectiveness and Safety of Codeine and Levodropropizine in Patients With Chronic Cough

BACKGROUND

Recent progress in chronic cough management includes controlling cough triggers and hypersensitivity using antitussives. Therefore, we investigated the effects and safety outcomes of antitussives, codeine and levodropropizine, in patients with chronic cough.

METHODS

We conducted an open-label, randomized comparative trial with newly referred patients with chronic cough. Patients were orally administered codeine (60 mg/day) and levodropropizine (180 mg/day) for 2 weeks. Cough severity, including the visual analog scale (VAS), Cough Symptom Score (CSS), Leicester Cough Questionnaire (LCQ), and safety for each treatment were assessed. The primary outcome was VAS score changes before and after 2 weeks of treatment.

RESULTS

Among the 88 participants, 45 and 43 in the codeine and levodropropizine groups, respectively, were included in the analysis. Changes in the VAS score were higher in the codeine group than in the levodropropizine group (35.11 ± 20.74 vs. 19.77 ± 24.83, P = 0.002). Patients administered codeine also had improved CSS (2.96 ± 2.35 vs. 1.26 ± 1.89, P < 0.001) and LCQ (3.28 ± 3.36 vs. 1.61 ± 3.53, P = 0.025) than those administered levodropropizine. Treatment-related adverse events, including drowsiness, constipation, and headaches, were more frequent in the codeine group than in the levodropropizine group. However, no significant differences existed in the adverse events leading to discontinuation.

CONCLUSION

Codeine is an effective and generally well-tolerated antitussive for chronic cough. However, it may induce side effects in some patients. Individual responses and adverse events should be carefully monitored when codeine is used to treat chronic cough.

Non-pharmacological Management of Non-productive Chronic Cough in Adults: A Systematic Review

Background

Chronic cough is a common reason for medical referral and its prevalence is on the rise. With only one pharmaceutical therapy currently under review for the treatment of refractory chronic cough, exploring non-pharmacological chronic cough management therapies is important. This systematic review summarizes the effectiveness of non-pharmacological chronic cough therapies in adults with non-productive refractory chronic cough or cough due to chronic respiratory diseases.

Methods

We searched Medline, Embase, Cochrane, CINAHL, and Scopus from inception to September 2021. Randomized controlled trials published in English, Portuguese, or French, and examining the effects of non-pharmacological therapies in adults with chronic non-productive cough (>8 weeks; <2 teaspoons sputum) were included. Mean differences, medians, and odds ratios were calculated as appropriate.

Results

16,546 articles were identified and six articles representing five unique studies were included. Studies evaluated 228 individuals with refractory chronic cough or chronic cough due to a chronic respiratory disease [162 women (71%); 52 ± 11 to 61 ± 8 years old]. Obstructive sleep apnea was the only chronic respiratory disease studied. Non-pharmacological therapies included education, cough suppression, breathing techniques, mindfulness, and continuous positive airway pressure. When standing alone, non-pharmacological cough therapies improved cough-specific health related quality of life when not associated with interventions (mean diff MD 1.53 to 4.54), cough frequency (MD 0.59 95%CI 0.36 to 0.95), and voice outcomes (MD 0.3 to 1) when compared to control interventions.

Conclusion

The evidence of non-pharmacological therapies for non-productive chronic cough is limited. Existing studies reflect the heterogeneity in study design, sample size, and outcome measures. Thus, clinical recommendations for using the most effective interventions remain to be confirmed.

A Breathable, Reusable, and Zero-Power Smart Face Mask for Wireless Cough and Mask-Wearing Monitoring

We herein introduce a lightweight and zero-power smart face mask, capable of wirelessly monitoring coughs in real time and identifying proper mask wearing in public places during a pandemic. The smart face mask relies on the compact, battery-free radio frequency (RF) harmonic transponder, which is attached to the inner layer of the mask for detecting its separation from the face. Specifically, the RF transponder composed of miniature antennas and passive frequency multiplier is made of spray-printed silver nanowires (AgNWs) coated with a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) passivation layer and the recently discovered multiscale porous polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) substrate. Unlike conventional on-chip or on-board wireless sensors, the SEBS-AgNWs/PEDOT:PSS-based RF transponder is lightweight, stretchable, breathable, and comfortable. In addition, this wireless device has excellent resilience and robustness in long-term and repeated usages (i.e., repeated placement and removal of the soft transponder on the mask). We foresee that this wireless smart face mask, providing simultaneous cough and mask-wearing monitoring, may mitigate virus-transmissive events by tracking the potential contagious person and identifying mask-wearing conditions. Moreover, the ability to wirelessly assess cough frequencies may improve diagnosis accuracy for dealing with several diseases, such as chronic obstructive pulmonary disease.

Past and Trends in Cough Sound Acquisition, Automatic Detection and Automatic Classification: A Comparative Review

Cough is a very common symptom and the most frequent reason for seeking medical advice. Optimized care goes inevitably through an adapted recording of this symptom and automatic processing. This study provides an updated exhaustive quantitative review of the field of cough sound acquisition, automatic detection in longer audio sequences and automatic classification of the nature or disease. Related studies were analyzed and metrics extracted and processed to create a quantitative characterization of the state-of-the-art and trends. A list of objective criteria was established to select a subset of the most complete detection studies in the perspective of deployment in clinical practice. One hundred and forty-four studies were short-listed, and a picture of the state-of-the-art technology is drawn. The trend shows an increasing number of classification studies, an increase of the dataset size, in part from crowdsourcing, a rapid increase of COVID-19 studies, the prevalence of smartphones and wearable sensors for the acquisition, and a rapid expansion of deep learning. Finally, a subset of 12 detection studies is identified as the most complete ones. An unequaled quantitative overview is presented. The field shows a remarkable dynamic, boosted by the research on COVID-19 diagnosis, and a perfect adaptation to mobile health.

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].

Blood eosinophils as a predictor of treatment response in adults with difficult-to-treat chronic cough

There is lack of evidence on the role of blood eosinophil count (BEC) as a predictor of treatment response in patients with chronic cough. The study aimed to evaluate BEC as a predictor of treatment response in all non-smoking adults with chronic cough and normal chest radiograph referred to cough clinic and in a subgroup of patients with chronic cough due to asthma or non-asthmatic eosinophilic bronchitis (NAEB).

This prospective cohort study included 142 consecutive, non-smoking patients referred to our cough centre due to chronic cough. The management of chronic cough was performed according to the current recommendations. At least a 30-mm decrease of 100-mm visual analogue scale in cough severity and a 1.3 points improvement in Leicester Cough Questionnaire were classified as a good therapeutic response.

There was a predominance of females (72.5%), median age 57.5 years with long-lasting, severe cough (median cough duration 60 months, severity 55/100 mm). Asthma and NAEB were diagnosed in 47.2% and 4.9% of patients, respectively. After 12–16 weeks of therapy, a good response to chronic cough treatment was found in 31.0% of all patients. A weak positive correlation was demonstrated between reduction in cough severity and BEC (r=0.28, p<0.001). Area under the curve for all patients with chronic cough was 0.62 with the optimal BEC cut-off for prediction of treatment response set at 237 cells·µL⁻¹ and for patients with chronic cough due to asthma/NAEB was 0.68 (95% CI 0.55–0.81) with the cut-off at 150 cells·µL⁻¹.

BEC is a poor predictor of treatment response in adults with chronic cough treated in the cough centre.

Evaluation of blood eosinophil count has limited value in prediction of therapeutic response in patients with difficult-to-treat chronic coughhttps://bit.ly/3EjaYsZ

Validation of a visual analog scale for assessing cough severity in patients with chronic cough

Introduction:

Patients with chronic cough experience considerable burden. The cough severity visual analog scale (VAS) records patients’ assessment of cough severity on a 100-mm linear scale ranging from “no cough” (0 mm) to “worst cough” (100 mm). Although cough severity scales are widely used in clinical practice and research, their use in patients with refractory or unexplained chronic cough has not been formally validated.

Methods:

This analysis includes data from a phase 2b randomized controlled trial of the P2X3-receptor antagonist gefapixant for treatment of refractory or unexplained chronic cough (NCT02612610). Cough severity VAS scores were assessed at baseline and Weeks 4, 8, and 12. The cough severity VAS was validated using several outcomes, including the Cough Severity Diary (CSD), Leicester Cough Questionnaire (LCQ), patient global impression of change (PGIC) scale, and objective cough frequency. Validation metrics included test–retest reliability, convergent and known-groups validity, responsiveness, and score interpretation (i.e., clinically meaningful change threshold).

Results:

The analysis included 253 patients (median age, 61.0 years; females, 76%). Test–retest reliability of the cough severity VAS was moderate (intraclass correlation coefficient, 0.51). The cough severity VAS had acceptable convergent validity with other related measures (Pearson r of 0.53 and -0.41 for CSD and LCQ total scores, respectively; p < 0.0001 for each). Known-groups validity was supported by significant differences in mean cough severity VAS scores across severity groups defined using CSD, LCQ, and cough frequency tertiles. A large effect size was observed in patients with the greatest improvements in PGIC (Cohen d = -1.8). A ⩾ 30-mm reduction in the cough severity VAS was estimated as a clinically meaningful change threshold for clinical trials in chronic cough.

Conclusions:

The cough severity VAS is a valid and responsive measure. A cough severity VAS reduction of ⩾ 30 mm can discriminate clinically meaningful changes in chronic cough severity in clinical studies.

Feasibility and clinical utility of ambulatory cough monitoring in an outpatient clinical setting: a real-world retrospective evaluation

RESEARCH QUESTION

Objective quantification of cough is rarely utilised outside of research settings and the role of cough frequency monitoring in clinical practice has not been established. This study examined the clinical utility of cough frequency monitoring in an outpatient clinical setting.

METHODS

The study involved a retrospective review of cough monitor data. Participants included 174 patients referred for treatment of cough and upper airway symptoms (103 chronic cough; 50 inducible laryngeal obstruction; 21 severe asthma) and 15 controls. Measures, taken prior to treatment, included 24-h ambulatory cough frequency using the Leicester Cough Monitor, the Leicester Cough Questionnaire and Laryngeal Hypersensitivity Questionnaire. Post-treatment data were available for 50 participants. Feasibility and clinical utility were also reported.

RESULTS

Analysis time per recording was up to 10 min. 75% of participants could use the monitors correctly, and most (93%) recordings were interpretable. The geometric mean cough frequency in patients was 10.1±2.9 (mean±sd) compared to 2.4±2.0 for healthy controls (p=0.003). There was no significant difference in cough frequency between clinical groups (p=0.080). Cough frequency decreased significantly following treatment (p<0.001). There was a moderate correlation between cough frequency and both cough quality of life and laryngeal hypersensitivity. Cough frequency monitoring was responsive to therapy and able to discriminate differences in cough frequency between diseases.

CONCLUSION

While ambulatory cough frequency monitoring remains a research tool, it provides useful clinical data that can assist in patient management. Logistical issues may preclude use in some clinical settings, and additional time needs to be allocated to the process.

Predictive Value of Cough Frequency in Addition to Aspiration Risk for Increased Risk of Pneumonia in Dysphagic Stroke Survivors: A Clinical Pilot Study

BACKGROUND

Post-stroke dysphagia leads to increased risk of aspiration and subsequent higher risk of pneumonia. It is important to not only diagnose post-stroke dysphagia early but also to evaluate the protective mechanism that counteracts aspiration, i.e., primarily cough. The aim of this study was to investigate the predictive value of cough frequency in addition to aspiration risk for pneumonia outcome.

METHODS

This was a single-center prospective observational study. Patients with first-ever strokes underwent clinical swallowing evaluation, fibreoptic endoscopic evaluation of swallowing (FEES), and overnight cough recording using LEOSound^® (Löwenstein Medical GmbH & Co. KG, Bad Ems, Germany ). Penetration-Aspiration Scale (PAS) ratings and cough frequency measurements were correlated with incidence of pneumonia at discharge.

RESULTS

11 women (37%) and 19 men (63%), mean age 70.3 years (SD ± 10.6), with ischemic stroke and dysphagia were enrolled. Correlation analysis showed statistically significant relationships between pneumonia and PAS (r = 0.521; p < 0.05), hourly cough frequency (r = 0,441; p < 0.05), and categories of cough severity (r = 0.428 p < 0.05), respectively. Logistic regression showed significant predictive effects of PAS (b = 0.687; p = 0.014) and cough frequency (b = 0.239; p = 0.041) for pneumonia outcome.

CONCLUSION

Cough frequency in addition to aspiration risk was an independent predictor of pneumonia in dysphagic stroke survivors.

Symptom Tracking and Experimentation Platform for Covid-19 or Similar Infections

Remote symptom tracking is critical for the prevention of Covid-19 spread. The qualified medical staff working in the call centers of primary health care units have to take critical decisions often based on vague information about the patient condition. The congestion and the medical protocols that are constantly changing often lead to incorrect decisions. The proposed platform allows the remote assessment of symptoms and can be useful for patients, health institutes and researchers. It consists of mobile desktop applications and medical sensors connected to cloud infrastructure. The unique features offered by the proposed solution are: (a) dynamic adaptation of Medical Protocols (MP) is supported (for the definition of alert rules, sensor sampling strategy and questionnaire structure) covering different medical cases (pre- or post-hospitalization, vulnerable population, etc.), (b) anonymous medical data can be statistically processed in the context of the research about an infection such as Covid-19, (c) reliable diagnosis is supported since several factors are taken into consideration, (d) the platform can be used to drastically reduce the congestion in various healthcare units. For the demonstration of (b), new classification methods based on similarity metrics have been tested for cough sound classification with an accuracy in the order of 90%.

Efficacy of broccoli and glucoraphanin in COVID-19: From hypothesis to proof-of-concept with three experimental clinical cases

COVID-19 is described in a clinical case involving a patient who proposed the hypothesis that Nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-interacting nutrients may help to prevent severe COVID-19 symptoms. Capsules of broccoli seeds containing glucoraphanin were being taken before the onset of SARS-CoV-2 infection and were continued daily for over a month after the first COVID-19 symptoms. They were found to reduce many of the symptoms rapidly and for a duration of 6-12 h by repeated dosing. When the patient was stable but still suffering from cough and nasal obstruction when not taking the broccoli capsules, a double-blind induced cough challenge confirmed the speed of onset of the capsules (less than 10 min). A second clinical case with lower broccoli doses carried out during the cytokine storm confirmed the clinical benefits already observed. A third clinical case showed similar effects at the onset of symptoms. In the first clinical trial, we used a dose of under 600 μmol per day of glucoraphanin. However, such a high dose may induce pharmacologic effects that require careful examination before the performance of any study. It is likely that the fast onset of action is mediated through the TRPA1 channel. These experimental clinical cases represent a proof-of-concept confirming the hypothesis that Nrf2-interacting nutrients are effective in COVID-19. However, this cannot be used in practice before the availability of further safety data, and confirmation is necessary through proper trials on efficacy and safety.

Wheeze and cough measurements at night in children with respiratory symptoms

Background

Nocturnal cough and wheeze are important symptoms when diagnosing any respiratory disease in a child, but objective measurements of these symptoms are not performed.

Methods

The aim of our study was to analyze the use of an automated detection system to assess breath sounds objectively in comparison to cough and wheeze questionnaires and to evaluate its feasibility in clinical practice.

Results

Forty-nine recordings of thirty-nine children were processed (asthma n = 13; cystic fibrosis n = 2; pneumonia n = 5; suspicion of habit cough n = 7; prolonged, recurrent or chronic cough n = 13), and cough and asthma scores were compared to the objective nocturnal recordings. Time for audio-validation of recordings took between 2 and 40 min (mean: 14.22 min, (SD): 10.72). Accuracy of the automated measurement was higher for cough than for wheezing sounds. Nocturnal cough readings but not wheeze readings correlated with some of the corresponding scores.

Conclusion

To our knowledge this is the first study using a new device to assess nocturnal cough and obstructive breath sounds objectively in children with a wide variety of respiratory diseases. The assessment proved user friendly. We obtained additional information on nighttime symptoms, which would otherwise have remained obscure. Further studies to assess possible diagnostic and therapeutic benefits of this device are needed.

Characteristics of Asthma-related Nocturnal Cough: A Potential New Digital Biomarker

Introduction

The nature of nocturnal cough is largely unknown. It might be a valid marker for asthma control but very few studies characterized it as a basis for better defining its role and its use as clinical marker. This study investigated prevalence and characteristics of nocturnal cough in asthmatics over the course of four weeks.

Methods

In two centers, 94 adult patients with physician-diagnosed asthma were recruited. Patient-reported outcomes and nocturnal sensor data were collected by a smartphone with a chat-based study app.

Results

Patients coughed in 53% of 2212 nights (range: 0–345 coughs/night). Median coughs per hour were 0 (IQR 0–1). Nocturnal cough rates showed considerable inter-individual variance. The highest counts were measured in the first 30 min in bed (4.5-fold higher than rest of night). Eighty-six percent of coughs were part of a cough cluster. Clusters consisted of a median of two coughs (IQR 2–4). Nocturnal cough was persistent within patient.

Conclusion

To the best of the authors’ knowledge, this study is the first to describe prevalence and characteristics of nocturnal cough in asthma over a period of one month, demonstrating that it was a prevalent symptom with large variance between patients and high persistence within patients. Cough events in asthmatics were 4.5 times more frequent within the first 30 min in bed indicating a potential role of positional change, and not more frequent during the early morning hours. An important next step will investigate the association between nocturnal cough and asthma control.

Oral corticosteroids for post-infectious cough in adults: study protocol for a double-blind randomized placebo-controlled trial in Swiss family practices (OSPIC trial)

BACKGROUND

Cough is a common reason for patients to visit general practices. So-called post-infectious cough is defined as lasting 3 to 8 weeks after an upper respiratory tract infection. It can be disabling in daily activities, with substantial impact on physical and psychosocial health, leading to impaired quality of life and increased health care costs. Recommendations for the management of post-infectious cough in primary care are scarce and incoherent. A systematic review and meta-analysis of randomized clinical trials (RCT) assessing patient-relevant benefits and potential harms of available treatments identified six eligible RCTs assessing different treatment regimens (i.e. inhaled fluticasone propionate, inhaled budesonide, salbutamol plus ipratropium-bromide, montelukast, nociception-opioid-1-receptor agonist, codeine, gelatine). No RCT found clear patient-relevant benefits and most had an unclear or high risk of bias. Post-infectious cough is thought to be mediated by inflammatory processes that are also present in exacerbations of asthma or chronic obstructive pulmonary diseases for which there is strong evidence that oral corticosteroids provide patient-relevant benefit without relevant harm. We therefore plan to conduct the first RCT evaluating the effectiveness of oral corticosteroids for post-infectious cough.

METHODS

We are conducting a triple-blinded randomized-controlled and multicentred superiority trial in primary health care practices in Switzerland. We will include 204 adult patients who consult their general practitioner (GP) for a cough lasting 3 to 8 weeks following an upper respiratory tract infection. Participants will be randomly allocated to either the 5-day treatment with oral corticosteroids or placebo. The primary outcome is cough-related quality of life assessed by the Leicester Cough Questionnaire score 14 days after randomization. Secondary outcomes include cough-related quality of life at several time points, overall cessation of cough and adverse events.

DISCUSSION

This RCT will provide evidence on whether oral corticosteroids are beneficial and safe in patients with post-infectious cough. Results can have a substantial impact on the well-being and management of these patients in Switzerland and beyond. An evidence-based treatment for this condition may reduce re-consultations with GPs and spending for antitussive drugs, thus possibly having an impact on health care spending.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04232449 . Prospectively registered on 18 January 2020.

Design and rationale of two phase 3 randomised controlled trials (COUGH-1 and COUGH-2) of gefapixant, a P2X3 receptor antagonist, in refractory or unexplained chronic cough

Background

We present study designs, dose selection and preliminary patient characteristics from two phase 3 clinical trials of gefapixant, a P2X3 receptor antagonist, in refractory chronic cough (RCC) or unexplained chronic cough (UCC).

Methods

COUGH-1 (NCT03449134) and COUGH-2 (NCT03449147) are randomised, placebo-controlled, double-blind, parallel-group trials in subjects with RCC or UCC (age ≥18 years; cough duration ≥1 year; Cough Severity Visual Analogue Scale score ≥40 mm). The primary efficacy study periods are 12 weeks (40-week extension; COUGH-1) and 24 weeks (28-week extension; COUGH-2). Interventions include placebo, gefapixant 15 mg and gefapixant 45 mg (1:1:1 ratio). The primary efficacy endpoints are average 24-h cough frequency at Week 12 (COUGH-1) and Week 24 (COUGH-2). Awake cough frequency, patient-reported outcomes and responder analyses are secondary endpoints.

Results

The doses of 45 mg (to provide maximal efficacy and acceptable tolerability) and 15 mg (to provide acceptable efficacy and improved tolerability) were selected based on phase 1 and 2 studies. In COUGH-1, 730 participants have been randomised and treated; 74% are female with mean age of 59 years (39% over 65 years), and mean baseline duration of cough of 11.5 years. In COUGH-2, 1314 participants have been randomised and treated; 75% are female with mean age of 58 years (33% over 65 years), and mean baseline duration of cough of 11.1 years.

Conclusions

These global studies include participants with baseline characteristics consistent with previous RCC and UCC studies and will inform the efficacy and safety profile of gefapixant in the treatment of patients with RCC and UCC.

This protocol describes the design of two global, phase 3 studies with >2000 participants with refractory or unexplained chronic cough, designed to confirm efficacy and safety of gefapixant, a P2X3 receptor antagonist, at doses of 45 mg and 15 mghttps://bit.ly/2Xzgu74

Disease control in patients with asthma and respiratory symptoms (wheezing, cough) during sleep

INTRODUCTION

The Global Initiative for Asthma (GINA)-defined criteria for asthma control include questions about daytime symptoms, limitation of activity, nocturnal symptoms, need for reliever treatment and patients' satisfaction. Patients with nocturnal symptoms like wheezing and cough often suffer from lower sleep quality and impaired daytime performance. The lack of an appropriate method for standardized and objective monitoring of respiratory symptoms leads to difficulties in asthma management. The aim of this study is to present a new method for automated wheeze and cough detection during sleep and to assess the actual level of asthma control by the Asthma Control Test (ACT).

METHODS

Respiratory symptoms like wheezing and cough were recorded with the LEOSound-Monitor for one night in 55 asthmatic patients in their individual domestic setting. Patients were asked to assess their level of asthma subjectively with the ACT. The study consisted of 37 women and 18 men, with a mean age of 41 years, and a mean BMI of 27 kg/m2. Most of the patients had been taking an ICS/LABA combination and would resort to a SABA as their rescue medication.

RESULTS

60% of the participants were classed as having controlled, and 40% were classed as having partially- or uncontrolled asthma. During sleep wheezing was found in 8 of the 55 asthma patients (14.5%) and coughing was found in 30 patients (54.5%). The median ACT score in wheezing-patients was 14, while in non-wheezing patients it was 21. Uncontrolled asthma was found in 6 of the 8 wheezing-patients. Coughing versus non-coughing patients did not show a significant difference in the ACT-score (20, 22 respectively).

CONCLUSION

Wheezing is a sign of uncontrolled asthma. The ACT-score in wheezing patients is worse compared to patients without wheezing. LEOSound proofed to be a useful tool in providing an objective evaluation of respiratory symptoms, like coughing and wheezing. In clinical practice, this may allow an improvement in asthma therapy.

The present and future of cough counting tools

The widespread use of cough counting tools has, to date, been limited by a reliance on human input to determine cough frequency. However, over the last two decades advances in digital technology and audio capture have reduced this dependence. As a result, cough frequency is increasingly recognised as a measurable parameter of respiratory disease. Cough frequency is now the gold standard primary endpoint for trials of new treatments for chronic cough, has been investigated as a marker of infectiousness in tuberculosis (TB), and used to demonstrate recovery in exacerbations of chronic obstructive pulmonary disease (COPD). This review discusses the principles of automatic cough detection and summarises key currently and recently used cough counting technology in clinical research. It additionally makes some predictions on future directions in the field based on recent developments. It seems likely that newer approaches to signal processing, the adoption of techniques from automatic speech recognition, and the widespread ownership of mobile devices will help drive forward the development of real-time fully automated ambulatory cough frequency monitoring over the coming years. These changes should allow cough counting systems to transition from their current status as a niche research tool in chronic cough to a much more widely applicable method for assessing, investigating and understanding respiratory disease.

The impact of a heat and moisture exchange mask on respiratory symptoms and airway response to exercise in asthma

Respiratory symptoms, including cough, are prevalent in individuals with asthma when exercising. This study investigates whether a heat and moisture exchanger (HME) face mask is effective in modulating exercise-induced bronchoconstriction (EIB) and post-exercise cough in a cold, dry environment in individuals with asthma.

Twenty-six participants diagnosed with asthma (20 males, 6 females) completed three cycling exercise challenges at 8°C and 24% relative humidity in a randomised order. Participants wore either an HME mask (MASK), sham mask (SHAM), or no mask (CONT). Following a 3-min warm-up, participants completed 6-min cycling at 80% peak power output. Before and after exercise, maximal flow-volume loops were recorded. Post-exercise cough was monitored with a Leicester Cough Monitor (LCM) for 24 h. Results were analysed using repeated-measures ANOVA and Friedman's tests and data were presented as the mean±sd or median (interquartile range (IQR)).

Eleven participants failed to demonstrate EIB (i.e. >10% fall in forced expiratory volume in 1 s after exercise) and were removed from analysis. The percentage fall in forced expiratory volume in 1 s following exercise in CONT was greater than MASK (MASK: −6% (7%), SHAM: −11% (11%), CONT: −13% (9%); p<0.01). No difference was found between exercise in cough count per hour over the 24-h monitoring period or the number of coughs in the first hour after exercise.

HME masks can attenuate EIB when exercising in cold, dry environments. The SHAM mask may not have been entirely inert, demonstrating the challenges of running randomised control trials utilising control and sham conditions.

Heat and moisture exchanger masks can reduce bronchoconstriction in individuals with exercise-induced bronchoconstriction when exercising in cold, dry environmentshttps://bit.ly/2JKeLnX

Comparison of midazolam and low-dose dexmedetomidine in flexible bronchoscopy: A prospective, randomized, double-blinded study

BACKGROUND

Dexmedetomidine is a clinically useful drug for providing sedation, but concern regarding its cardiovascular side effect profile can limit its widespread use during routine diagnostic flexible bronchoscopy (FB).

MATERIALS AND METHODS

Patients between 18 and 65 years of age, who required diagnostic FB, were screened. Eligible patients were randomized to either receive 0.5 μg/kg intravenous dexmedetomidine over 10 min or intravenous midazolam 0.035 mg/kg over 1 min. If required, rescue medication (intravenous midazolam 0.5 mg bolus) was administered. The primary outcome measure was the composite score. Other parameters observed were numerical rating scale, hemodynamic variables, oxygen saturation, number of doses of rescue medication, visual analog scale score for cough, ease of bronchoscopy, Ramsay Sedation Score, and postprocedure patient response after 24 h of bronchoscopy.

RESULTS

A total of 54 patients were enrolled, 27 in each group. Total composite score (mean ± standard deviation) in dexmedetomidine and midazolam group at nasopharynx was 7.04 ± 2.19 and 6.59 ± 1.55 (P = 0.387), respectively. The corresponding values at the level of trachea were 9.22 ± 3.69 and 8.63 ± 2.13 (P = 0.475). In the dexmedetomidine group, patient response after 24 h of bronchoscopy showed the quality of sedation to be excellent in three patients, good in 10, fair in 11, and poor in 3 and discomfort to be nil in 14, mild 7, moderate in 3, and severe in 3. The corresponding values in the midazolam group for the quality of sedation were 0, 9, 18, 0 and for discomfort 10, 16, 1, 0. Other parameters did not reveal any statistically significant difference.

CONCLUSION

Dexmedetomidine at a dose of 0.5 μg/kg may provide clinically useful conscious sedation, comparable to midazolam.

Quantitative measurement properties and score interpretation of the Cough Severity Diary in patients with chronic cough

AIMS

The Cough Severity Diary (CSD) was developed in accordance with the FDA guidance for patient-reported outcome measures and is focused on capturing the patient's perception of cough in terms of frequency, intensity, and disruption due to their cough. The measure includes a series of seven items asking patients to rate the frequency (three items), intensity (two items), and disruptiveness (two items) of their cough. The instrument was designed to be completed daily before bedtime, has a recall period of 'today,' and responses to items are entered on an 11-point numeric rating scale ranging from 0 to 10 with anchors on each end. The objective of this analysis was to confirm the domain structure of the CSD and assess its reliability, validity, and responsiveness in adult patients with refractory or unexplained chronic cough (RCC/UCC). Criteria for defining meaningful changes in mean weekly CSD total and domain scores in the context of a clinical trial were also developed.

METHODS

Pooled data from a phase II randomized controlled trial of an investigational treatment for RCC/UCC were analyzed. Participants were non-smokers, had RCC/UCC for ⩾1 year, and a baseline cough severity visual analogue scale (VAS) ⩾40 mm. CSD scores (baseline, week 4), were analyzed; the Leicester Cough Questionnaire (LCQ), cough severity VAS, Patient Global Impression of Change (PGIC), and objective cough frequency counts were used for validation. CSD domain structure (Total, Frequency, Intensity, Disruption) was assessed for scoring.

RESULTS

A total of 253 participants were included (mean age 60.2; 76% female). Global fit of the three-factor CSD was acceptable. For the CSD total score, internal consistency (α = 0.89) and test-retest reliability (intraclass correlation coefficient = 0.68) were high. CSD total scores were correlated with the LCQ total (r = -0.62) and cough severity VAS (r = 0.84). Participants with a PGIC score of 1 or 2 (most improved groups) had the greatest mean score improvement on the CSD Total (Day 0 to Day 28), supporting responsiveness (similar findings for subscales). A change threshold of ⩾1.3-point reduction on the total and subscale scores is appropriate to define clinically meaningful improvement.

CONCLUSION

The CSD is a reliable, valid, and responsive measure of cough symptom severity in patients with refractory or unexplained chronic cough and fit-for-purpose for assessing changes in cough severity in clinical trials. The reviews of this paper are available via the supplemental material section.

Clinical Characteristics of Chronic Cough in Korea

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Continuous Sound Collection Using Smartphones and Machine Learning to Measure Cough

Background

Despite the efforts of research groups to develop and implement at least partial automation, cough counting remains impractical. Analysis of 24-h cough frequency is an established regulatory endpoint which, if addressed in an automated manner, has the potential to ease cough symptom evaluation over multiple 24-h periods in a patient-centric way, supporting the development of novel treatments for chronic cough, an unmet clinical need.

Objectives

In light of recent technological advancements, we propose a system based on the use of smartphones for objective continuous sound collection, suitable for automated cough detection and analysis. Two capabilities were identified as necessary for naturalistic cough assessment: (1) recording sound in a continuous manner (sound collection), and (2) detection of coughs from the recorded sound (cough detection).

Methods

This work did not involve any human subject testing or trials. For sound collection, we designed, built, and verified technical parameters of a smartphone application for sound collection. Our cough detection work describes the development of a mathematical model for sound analysis and cough identification. Performance of the model was compared to previously published results of commercially available solutions and to human raters. The compared solutions use the following methods to automatically or semi-automatically assess cough: 24-h sound recording with an ambulatory device with multiple microphones, automatic silence removal, and manual recording review for cough count.

Results

Sound collection: the application demonstrated the ability to continuously record sounds using the phone's internal microphone; the technical verification informed the configuration of the technical and user experience parameters. Cough detection: our cough recognition sensitivity to cough as determined by human listeners was 90 at 99.5% specificity preset and 75 at 99.9% specificity preset for a dataset created from publicly available data.

Conclusions

Sound collection: the application reliably collects sound data and uploads them securely to a remote server for subsequent analysis; the developed sound data collection application is a critical first step toward future incorporation in clinical trials. Cough detection: initial experiments with cough detection techniques yielded encouraging results for application to patient-collected data from future studies.

Types and applications of cough-related questionnaires

Cough is a normal protective reflex that can effectively remove foreign bodies and secretions from the airway. However, excessive cough adversely affects a patient's physiological, psychological and social functions. Thus, it is important to effectively evaluate the severity of cough to determine its diagnosis and treatment. Cough severity can be assessed with subjective or objective tools. Herein, we summarize the subjective evaluation of cough severity with questionnaires.

Time course of nocturnal cough and wheezing in children with acute bronchitis monitored by lung sound analysis

Cough and wheezing are the predominant symptoms of acute bronchitis. Hitherto, the evaluation of respiratory symptoms was limited to subjective methods such as questionnaires. The main objective of this study was to objectively determine the time course of cough and wheezing in children with acute bronchitis. The impact of nocturnal cough on parent's quality of life was assessed as secondary outcome. In 36 children (2-8 years), the frequency of nocturnal cough and wheezing was recorded during three nights by automated lung sound monitoring. Additionally, parents completed symptom logs, i.e., the Bronchitis Severity Score (BSS), as well as the Parent-proxy Children's Acute Cough-specific Quality of Life Questionnaire (PAC-QoL). During the first night, patients had 34.4 ± 52.3 (mean ± SD) cough epochs, which were significantly reduced in night 5 (13.5 ± 26.5; p < 0.001) and night 9 (12.8 ± 28.1; p < 0.001). Twenty-two patients had concomitant wheezing, which declined within the observation period as well. All subjective parameters (BSS, Cough log and PAC-QoL) were found to be significantly correlated with the objectively assessed cough parameters.Conclusion: Long-term recording of cough and wheezing offers a useful opportunity to objectively evaluate the time course of respiratory symptoms in children with acute bronchitis. To assess putative effects of pharmacotherapy on nocturnal bronchitis symptoms, future studies in more homogeneous patient groups are needed. What is Known: • Cough and wheezing are the predominant symptoms of acute bronchitis. • There is a diagnostic gap in long-term assessment of these respiratory symptoms, which needs to be closed to optimize individual therapies. What is New: • Long-term recording of nocturnal cough and wheezing allows for objective evaluation of respiratory symptoms in children with acute bronchitis and provides a tool to validate the efficacy of symptomatic bronchitis therapies.

Association between postoperative cough and thyroidectomy: a prospective study

Background

This study sought to determine whether thyroidectomy is associated with self-reported cough through a prospective analysis.

Methods

Patients undergoing unilateral thyroidectomy were prospectively enrolled. The control group was selected to avoid the effect of general anaesthesia. The experimental group consisted of 300 patients (202 females and 98 males) who underwent thyroidectomy, with a mean age of 48.6 years, and the control group consisted of 103 patients (53 females and 50 males) who underwent other head and neck operations, with a mean age of 50.3 years. All patients were required to complete the Leicester Cough Questionnaire (LCQ) preoperatively and 2 weeks postoperatively.

Results

The postoperative mean total LCQ scores in the experimental and control groups were 17.9 ± 5.0 and 19.8 ± 4.2, respectively; the difference was significant (p = 0.014). Adverse event analysis showed that patients in the experimental group scored significantly worse on items for chest or stomach pains, phlegm, feeling in control of coughing, sleep disturbances, coughing bouts, frustration, and feeling fed up with coughing. In the analysis of the three LCQ domains, a significant difference was noted in the physical domain between the two groups (p < 0.001). In the one-way analysis of variance, the factors of sex and anaesthesia time were associated with the postoperative LCQ score; in further multifactor analysis of variance, only the factor of sex was significantly related to the postoperative LCQ score.

Conclusion

Thyroidectomy may be associated with postoperative cough, and a higher number of female patients complained of cough and related symptoms.

Effect of anti-reflux treatment on gastroesophageal reflux-associated chronic cough: Implications of neurogenic and neutrophilic inflammation

Objective: Gastroesophageal reflux disease (GERD) is an important cause of chronic cough. Substance P (SP) has been implicated in the pathophysiology of cough. Proton pump inhibitors (PPIs) and prokinetic agents are the current treatment for GER-associated cough. The aim was to evaluate the effects of anti-reflux treatment and its associations with cellular and neurogenic inflammation.Methods: Thirty-seven patients with GER-associated cough suspected based on characteristic symptoms such as heartburn and worsening of cough by phonation and rising were recruited. A PPI, rabeprazole 20 mg daily, and a prokinetic agent, itopride 50 mg t.i.d., were administered for 4 weeks in a prospective, observational manner. Before and after treatment, subjective cough measures [visual analog scale (VAS) and the Japanese version of the Leicester Cough Questionnaire (J-LCQ)], the modified frequency scale for the symptoms of GERD [FSSG, consisting of 2 domains: acid-reflux (AR) and functional dyspepsia symptoms], sputum and plasma SP levels, and sputum cell differentials were examined. Patients with good response to treatment [Δ (decrease of) VAS >15 mm; n = 21) were compared with poor responders (ΔVAS ≤15 mm).Results: Anti-reflux treatment significantly improved the cough VAS, J-LCQ, and AR symptoms, and ΔVAS and ΔAR were significantly correlated. Decreases of plasma and sputum SP levels and sputum neutrophil counts were significantly greater in responders than in poor responders. Both baseline values and post-treatment changes of plasma SP and sputum neutrophils were significantly correlated for all patients.Conclusions: Successful treatment of GER-associated cough may be associated with the attenuation of neurogenic and neutrophilic inflammation.

[Chronic cough in children]

Coughing is one of the most common patient complaints at physicians' office. The majority of children experience 5 to 8 episodes of cough lasting about a week throughout the year. Episodes of cough which last longer than 4 weeks, defined as a chronic cough, result in serious parental concern, impaired quality of life, increased number of medical consultations and the adverse effects of inappropriately used medications. Overall, a chronic cough is not only a serious health problem, but also a social one. The article presented below summarizes our current knowledge on the pathophysiology of chronic cough, the latest diagnostics and most recent measurement and monitoring methods as well as recommendations for therapeutic proceedings. In order to emphasize the distinct pathophysiology of chronic cough we use a new term: cough hypersensitivity syndrome. We point out the necessity of the concurrent implementation of more than one cough monitoring method for its more adequate evaluation. This article in addition presents the diagnostic and therapeutic algorithms in the treatment of a chronic cough which shorten the time to make a proper diagnosis, enable the introduction of adequate treatment, and ultimately improve the patients' quality of life. We present new therapeutic strategies, which are based on regulating the activity of vagal afferent nerves and modifying the neurotransmiters' transmission in the brainstem and midbrain.

Prevalence of nocturnal cough in asthma and its potential as a marker for asthma control (MAC) in combination with sleep quality: protocol of a smartphone-based, multicentre, longitudinal observational study with two stages

INTRODUCTION

Nocturnal cough is a burdensome asthma symptom. However, knowledge about the prevalence of nocturnal cough in asthma is limited. Furthermore, prior research has shown that nocturnal cough and impaired sleep quality are associated with asthma control, but the association between these two symptoms remains unclear. This study further investigates the potential of these symptoms as markers for asthma control and the accuracy of automated, smartphone-based passive monitoring for nocturnal cough detection and sleep quality assessment.

METHODS AND ANALYSIS

The study is a multicentre, longitudinal observational study with two stages. Sensor and questionnaire data of 94 individuals with asthma will be recorded for 28 nights by means of a smartphone. On the first and the last study day, a participant's asthma will be clinically assessed, including spirometry and fractionated exhaled nitric oxide levels. Asthma control will be assessed by the Asthma Control Test and sleep quality by means of the Pittsburgh Sleep Quality Index. In addition, nocturnal coughs from smartphone microphone recordings will be labelled and counted by human annotators. Relatively unrestrictive eligibility criteria for study participation are set to support external validity of study results. Analysis of the first stage is concerned with the prevalence and trends of nocturnal cough and the accuracies of smartphone-based automated detection of nocturnal cough and sleep quality. In the second stage, patient-reported asthma control will be predicted in a mixed effects regression model with nocturnal cough frequencies and sleep quality of past nights as the main predictors.

ETHICS AND DISSEMINATION

The study was reviewed and approved by the ethics commission responsible for research involving humans in eastern Switzerland (BASEC ID: 2017-01872). All study data will be anonymised on study termination. Results will be published in medical and technical peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03635710; Pre-results.

Estimation of Cough Peak Flow Using Cough Sounds

Cough peak flow (CPF) is a measurement for evaluating the risk of cough dysfunction and can be measured using various devices, such as spirometers. However, complex device setup and the face mask required to be firmly attached to the mouth impose burdens on both patients and their caregivers. Therefore, this study develops a novel cough strength evaluation method using cough sounds. This paper presents an exponential model to estimate CPF from the cough peak sound pressure level (CPSL). We investigated the relationship between cough sounds and cough flows and the effects of a measurement condition of cough sound, microphone type and participant's height and gender on CPF estimation accuracy. The results confirmed that the proposed model estimated CPF with a high accuracy. The absolute error between CPFs and estimated CPFs were significantly lower when the microphone distance from the participant's mouth was within 30 cm than when the distance exceeded 30 cm. Analysis of the model parameters showed that the estimation accuracy was not affected by participant's height or gender. These results indicate that the proposed model has the potential to improve the feasibility of measuring and assessing CPF.

An update and systematic review on drug therapies for the treatment of refractory chronic cough

INTRODUCTION

Chronic Cough (CC) is common and often associated with significant comorbidity and decreased quality of life. In up to 50% of cases, the cough is refractory despite extensive investigation and treatment trials. It is likely that the key abnormality in refractory CC is dysfunctional, hypersensitive sensory nerves, similar to conditions such as laryngeal hypersensitivity and neuropathic pain.

AREAS COVERED

The aim of this systematic review is to assess drug therapies for refractory CC. The authors review the current management of CC and provide discussion of the similarities between neuropathic pain and refractory CC. They review repurposed and new pharmacological treatments. Several meta-analyses were performed to compare the efficacy of treatments where possible.

EXPERT OPINION

Repurposed pain medications such as gabapentin and pregabalin reduce the frequency of cough and improve quality of life. Along with speech pathology, they are important and alternate treatments for refractory CC. However, more treatments are needed and the P2X3 ion channel receptor antagonists show the most promise. With a better understanding of neuronal activation and sensitisation and their signal processing in the brain, improved animal models of cough, and the use of validated cough measurement tools, more effective treatments will develop.

Effectiveness of proton pump inhibitor in unexplained chronic cough

Background

Current guidelines recommend that patients with unexplained chronic cough undergo empirical proton pump inhibitor (PPI) treatment, but scientific evidence for this treatment is lacking. We investigated the effectiveness and appropriate dose of PPI therapy in chronic cough.

Methods

We included 27 patients with unexplained chronic cough after excluding subjects with positive response to postnasal drip medication. Subjects were randomized to a placebo, standard, and high dose of PPI groups with blinding. The drug or placebo was administered orally for 8 weeks, and the Leicester Cough Questionnaire (LCQ) score and visual analogue scale (VAS) scores were collected.

Results

The LCQ score in the PPI group significantly improved from 0 weeks (11.4 ± 1.4) to 4 weeks (14.8 ± 1.4) and to 8 weeks (17.1 ± 1.4), whereas that in the placebo group did not improve from 0 weeks (13.7 ± 1.1) to 8 weeks (11.8 ± 1.4); the difference between the 2 groups was significant (P < 0.001). In subgroup analysis according to reflux, significant improvements in the LCQ score were observed in the PPI group regardless of reflux (P < 0.001 in the reflux group and P < 0.001 in the no reflux group, respectively; P = 0.188 between the 2 groups). In addition, improvements in LCQ and VAS scores between the standard- and high-dose PPI groups were not significantly different; however, adverse reactions were induced by only the high dose (16.7%).

Conclusions

The results of this pilot study support the empirical use of the standard dose of PPI for 8 weeks in patients suffering from unexplained chronic cough regardless of whether reflux is present.

Trial registration

ClinicalTrial.gov NCT01888549 www.clinicaltrials.gov; cris.nih.go.kr KCT0000543 cris.nih.go.kr/

Dyspnoea, hyperventilation and functional cough: a guide to which tests help sort them out

Methods that can be used to investigate dyspnoea in a newly referred patient http://ow.ly/EsQW307U9hd.

Cough frequency monitors: can they discriminate patient from environmental coughs?

BACKGROUND

Objective cough frequency measurements are increasingly applied in clinical research. Technological advances enable automated detection and counting of cough events from sound recordings of many hours' duration. A possible limitation of sound-based cough frequency measurement is the contamination of recordings by environmental coughs (coughs from persons other than the patient). This study aimed to investigate the accuracy of a sound-based cough monitor for detecting and discriminating patient cough from environmental cough.

METHODS

As part of a stroke trial (ISRCTN40298220), patients on a hospital ward underwent 15-minute recordings using the Leicester Cough Monitor (LCM), a sound-based cough monitor ('semi-automated counts'). Participants and other persons in the environment were prompted to cough. An observer present in the room recorded the number of patient and environmental coughs ('live counts'). LCM counts were also compared against a manual cough count, the most commonly used gold standard to determine accuracy ('manual sound counts' from listening to recordings), by a blinded assessor who cross-referenced timed cough events from the respective methods. Data for automated, manual and live cough counts were analyzed using agreement statistics.

RESULTS

On sound recordings from five patients, there were 65 patient coughs and 78 environmental coughs (manual counts). Absolute agreement for patient cough count between all three measurement methods (LCM automated, live, and manual sound counts) was high, with intra-class correlation coefficient of 0.94 [95% confidence intervals (CI): 0.74, 0.99]. The proportion of exact agreements for patient cough between LCM and manual count was 0.92, and kappa was 0.84 (95% CI: 0.75, 0.93). The LCM showed sensitivity of 0.94 (95% CI: 0.84, 0.98), specificity of 0.91 (95% CI: 0.82, 0.96), positive predictive value of 0.90 (95% CI: 0.79, 0.95) and negative predictive value of 0.95 (95% CI: 0.86, 0.98) for detecting patient coughs.

CONCLUSIONS

This preliminary study supports the validity of the cough monitor for detecting and discriminating patient from environmental cough. Further validation is recommended, to describe the level of accuracy with greater precision.

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.

Efficacy and safety of Maekmoondong-tang for chronic dry cough: a study protocol for a randomized controlled trial

Background

Chronic cough, defined it lasts more than 8 weeks. The symptom is common, but highly troublesome, and it reduces quality of life. Despite much effort to develop a protocol for diagnosis and treatment of chronic cough, it remains problematic to determine its cause. As a result, treatment is often unsuccessful. Thus, there is much interest regarding the use of symptomatic drugs to control chronic cough.

Maekmoondong-tang is widely used in East Asian countries to treat chronic dry cough. Several experimental studies have reported that the herbal medicine has immunomodulatory and antitussive effects. Clinical studies involving Maekmoondong-tang have also been carried out; however, these studies have involved treating various diseases as a whole rather than chronic cough itself. Thus, we aim to evaluate the efficacy and safety of Maekmoondong-tang in chronic dry cough patients with a randomized controlled trial.

Methods/Design

This study is designed as an exploratory, single-center, placebo-controlled, double-blind, randomized, parallel group clinical trial. Patients with dry cough that has lasted more than 8 weeks will be recruited, after a 1-week run-in period, and randomly allocated to either the Maekmoondong-tang treatment group or the placebo group. The patients will receive Maekmoondong-tang or placebo granules 3 times daily for 4 weeks, with a 2-week follow-up. The primary outcome is a 10-point cough diary that will be recorded on a daily basis. The secondary outcomes comprise a cough visual analog scale, the Leicester Cough Questionnaire (Korean version), the Pattern Identification for Chronic Cough Questionnaire, biomarkers, safety testing, etc. Adverse events will also be reported.

Discussion

This trial will assess the efficacy and safety of Maekmoondong-tang in chronic dry cough.

Trial registration

Korean Clinical Trial Registry (http://cris.nih.go.kr; registration number: KCT0001646). Date of registration: October 5 2015

The correlation of symptoms, pulmonary function tests and exercise testing with high-resolution computed tomography in patients with idiopathic interstitial pneumonia in a tertiary care hospital in South India

CONTEXT

For the follow-up of patients with idiopathic interstitial pneumonias (IIP), it is unclear which parameters of pulmonary function tests (PFT) and exercise testing would correlate best with high-resolution computed tomography (HRCT)..

AIM

To find out the correlation of symptom scores, PFTs and exercise testing with HRCT scoring in patients diagnosed as idiopathic interstitial pneumonia.

SETTINGS AND DESIGN

Cross-sectional study done in pulmonary medicine outpatients department of a tertiary care hospital in South India.

MATERIALS AND METHODS

Consecutive patients who were diagnosed as IIP by a standard algorithm were included into the study. Cough and dyspnea were graded for severity and duration. Pulmonary function tests and exercise testing parameters were noted. HRCT was scored based on an alveolar score, an interstitial score and a total score. The HRCT was correlated with each of the clinical and physiologic parameters. Pearson's/Spearman's correlation coefficient was used for the correlation of symptoms and parameters of ABG, PFT and 6MWT with the HRCT scores.

RESULTS

A total of 94 patients were included in the study. Cough and dyspnea severity (r = 0.336 and 0.299), FVC (r = -0.48), TLC (r = -0.439) and DLCO and distance saturation product (DSP) (r = -0.368) and lowest saturation (r = -0.324) had significant correlation with total HRCT score. Among these, DLCO, particularly DLCO corrected % of predicted, correlated best with HRCT score (r = -0.721)..

CONCLUSION

Symptoms, PFT and exercise testing had good correlation with HRCT. DLCO corrected % of predicted correlated best with HRCT.