Causes and clinical features of subacute cough

Are Otolaryngologists Seeing More Cough? Longitudinal Trends and Patterns

OBJECTIVE

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

STUDY DESIGN

Nationally representative survey.

SETTING

National Ambulatory Medical Care Survey (NAMCS).

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Level 4.

Zhisou powder suppresses airway inflammation in LPS and CS-induced post-infectious cough model mice via TRPA1/TRPV1 channels

ETHNOPHARMACOLOGICAL RELEVANCE

Zhisou Powder (ZSP), a traditional Chinese medicine (TCM) prescription, has been widely used in the clinic for the treatment of post-infectious cough (PIC). However, the exact mechanism is not clear.

AIM OF THE STUDY

The aim of this study was to investigate the ameliorative effect of ZSP on PIC in mice. The possible mechanisms of action were screened based on network pharmacology, and the potential mechanisms were explored through molecular docking and in vivo experimental validation.

MATERIALS AND METHODS

Lipopolysaccharide (LPS) (80μg/50 μL) was used to induce PIC in mice, followed by daily exposure to cigarette smoke (CS) for 30 min for 30 d to establish PIC model. The effects of ZSP on PIC mice were observed by detecting the number of coughs and cough latency, peripheral blood and bronchoalveolar lavage fluid (BALF) inflammatory cell counts, enzyme-linked immunosorbent assay (ELISA), and histological analysis. The core targets and key pathways of ZSP on PIC were analyzed using network pharmacology, and TRPA1 and TRPV1 were validated using RT-qPCR and western blotting assays.

RESULTS

ZSP effectively reduced the number of coughs and prolonged the cough latency in PIC mice. Airway inflammation was alleviated by reducing the expression levels of the inflammatory mediators TNF-α and IL-1β. ZSP modulated the expression of Substance P, Calcitonin gene-related peptide (CGRP), and nerve growth factor (NGF) in BALF. Based on the results of network pharmacology, the mechanism of action of ZSP may exert anti-neurogenic airway-derived inflammation by regulating the expression of TRPA1 and TRPV1 through the natural active ingredients α-spinastero, shionone and didehydrotuberostemonine.

CONCLUSION

ZSP exerts anti-airway inflammatory effects through inhibition of TRPA1/TRPV1 channels regulating neuropeptides to alleviate cough hypersensitivity and has a favorable therapeutic effect on PIC model mice. It provides theoretical evidence for the clinical application of ZSP.

Novel Artificial Intelligence-Based Technology to Diagnose Asthma Using Methacholine Challenge Tests

PURPOSE

The methacholine challenge test (MCT) has high sensitivity but relatively low specificity for asthma diagnosis. This study aimed to develop and validate machine learning (ML) models to improve the diagnostic performance of MCT for asthma.

METHODS

Data from 1,501 patients with asthma symptoms who underwent MCT between 2015 and 2020 were analyzed. The patients were grouped as either the training (80%, n = 1,265) and test sets (20%, n = 236) depending on the time of referral. The conventional model (provocative concentration that causes a 20% decrease in forced expiratory volume in one second [FEV1]; PC20 ≤ 16 mg/mL) was compared with the prediction models derived from five ML methods: logistic regression, support vector machine, random forest, extreme gradient boosting, and artificial neural network. The area under the receiver operator characteristic curves (AUROC) and area under the precision-recall curves (AUPRC) of each model were compared. The prediction models were further analyzed using different input combinations of FEV1, forced vital capacity (FVC), and forced expiratory flow at 25%-75% of forced vital capacity (FEF25%-75%) values obtained during MCT.

RESULTS

In total, 545 patients (36.3%) were diagnosed with asthma. The AUROC of the conventional model was 0.856 (95% confidence interval [CI], 0.852-0.861), and the AUPRC was 0.759 (95% CI, 0.751-0.766). All the five ML prediction models had higher AUROC and AUPRC values than those of the conventional model, and random forest showed both highest AUROC (0.950; 95% CI, 0.948-0.952) and AUROC (0.909; 95% CI, 0.905-0.914) when FEV1, FVC, and FEF25%-75% were included as inputs.

CONCLUSIONS

Artificial intelligence-based models showed excellent performance in asthma prediction compared to using PC20 ≤ 16 mg/mL. The novel technology could be used to enhance the clinical diagnosis of asthma.

Cough and sputum in long COVID are associated with severe acute COVID-19: a Japanese cohort study

BACKGROUND

Multiple prolonged symptoms are observed in patients who recover from acute coronavirus disease 2019 (COVID-19), defined as long COVID. Cough and sputum are presented by patients with long COVID during the acute and post-acute phases. This study aimed to identify specific risk factors for cough and sputum in patients with long COVID.

METHODS

Hospitalized patients with COVID-19 aged 18 years were enrolled in a multicenter cohort study at 26 medical institutions. Clinical data during hospitalization and patient-reported outcomes after discharge were collected from medical records, paper-based questionnaires, and smartphone apps.

RESULTS

At the 3-, 6-, and 12-month follow-ups, there were no differences in the incidence rates of wet and dry coughs. In contrast, the proportion of patients presenting sputum without coughing increased over time compared to those with sputum and coughing. Univariate analyses of cough and sputum at all follow-up visits identified intermittent mandatory ventilation (IMV), smoking, and older age as risk factors for prolonged symptoms. At the 12-month follow-up, persistent cough and sputum were associated with the characteristics of severe COVID-19 based on imaging findings, renal and liver dysfunction, pulmonary thromboembolism, and higher serum levels of LDH, KL-6, and HbA1C. The Kaplan-Meier curves showed that the severity of acute COVID-19 infection was correlated with prolonged cough and sputum production. Multivariable logistic regression analysis showed that IMV ventilator management were independent risk factors for prolonged cough and sputum at 12 months.

CONCLUSIONS

In a Japanese population with long COVID, prolonged cough and sputum production were closely associated with severe COVID-19. These findings emphasize that a preventive approach including appropriate vaccination and contact precaution and further development of therapeutic drugs for COVID-19 are highly recommended for patients with risk factors for severe infection to avoid persistent respiratory symptoms.

Bacterial Etiology in Subacute Cough

Although postinfectious etiology is the most common cause of subacute cough, there are insufficient data on the epidemiology of associated bacterial infections. We aimed to identify the etiology of bacterial detection in subjects with subacute cough. A multicenter prospective observational study of 142 patients with postinfectious subacute cough was performed between August 2016 and December 2017 in Korea. We obtained 2 nasal swabs from each patient and used a multiplex bacterial polymerase chain reaction (PCR) kit that simultaneously detects Bordetella pertussis, Chlamydophila pneumoniae, Haemophilus influenzae, Legionella pneumophilia, Mycoplasma pneumoniae, and Streptococcus pneumoniae. About 29% (n = 41) of patients with subacute cough were positive for bacterial PCR in nasal swabs. The most common bacteria detected by bacterial PCR was H. influenzae (n = 19, 13.4%), followed by S. pneumoniae (n = 18, 12.7%), B. pertussis (n = 7, 4.9%), M. pneumoniae (n = 3, 2.1%), L. pneumophilia (n = 2, 1.4%), and C. pneumoniae (n = 1, 0.7%). Nine patients had dual positivity for the PCR. In conclusion, bacterial PCR was positive in the nasal swabs of about 29% of subjects with subacute cough, including 5% of positive PCR results for B. pertussis.

Association of lower plasma citric acid with prolonged cough: the Nagahama study

Little is known about the association of prolonged cough, a common and troublesome symptom, with metabolic pathways. We aimed to clarify this association using data from the Nagahama cohort, a prospective study of participants from the general population. Self-report questionnaires on prolonged cough were collected at baseline and 5-year follow-up assessments. Blood tests at follow-up were used for gas chromatography-mass spectrometry-based metabolomics. The association between metabolites and prolonged cough was examined using the partial least squares discriminant analysis and multiple regression analysis. Among the 7432 participants, 632 had newly developed prolonged cough at follow-up, which was defined as "new-onset prolonged cough". Low plasma citric acid was significantly associated with new-onset prolonged cough, even after the adjustment of confounding factors including the presence of asthma, upper airway cough syndrome (UACS), and gastroesophageal reflux disease (GERD). A similar association was observed for isocitric acid, 3-hydroxybutyric acid, and 3-hydroxyisobutyric acid. The analysis of these four metabolites revealed that citric acid had the strongest association with new-onset prolonged cough. This significant association remained even when the analysis was confined to participants with UACS or GERD at baseline or follow-up, and these associations were also observed in participants (n = 976) who had prolonged cough at follow-up regardless of baseline status. In conclusion, low blood citric acid may be associated with prolonged cough.

Otolaryngologic Symptom Severity Post SARS-CoV-2 Infection

Objective(s)

To assess laryngologic symptomatology following SARS-CoV-2 infection and determine whether symptom severity correlates with disease severity.

Methods

Single-institution survey study in participants with documented SARS-CoV-2 infection between March 2020 and February 2021. Data acquired included demographic, infection severity characteristics, comorbidities, and current upper aerodigestive symptoms via validated patient reported outcome measures.  Primary outcomes of interest were scores of symptom severity questionnaires. COVID-19 severity was defined by hospitalization status. Descriptive subgroup analyses were performed to investigate differences in demographics, comorbidities, and symptom severity in hospitalized participants stratified by ICU status. Multivariate logistical regression was used to evaluate significant differences in symptom severity scores by hospitalization status.

Results

Surveys were distributed to 5300 individuals with upper respiratory infections. Ultimately, 470 participants with COVID-19 were included where 352 were hospitalized and 118 were not hospitalized. Those not hospitalized were younger (45.87 vs. 56.28 years), more likely female (74.17 vs. 58.92%), and less likely white (44.17 vs. 52.41%). Severity of dysphonia, dyspnea, cough, and dysphagia was significantly worse in hospitalized patients overall and remained worse at all time points. Cough severity paradoxically worsened in hospitalized respondents over time. Dyspnea scores remained abnormally elevated in respondents even 12 months after resolution of infection.

Conclusion

Results indicate that laryngologic symptoms are expected to be worse in patients hospitalized with COVID-19. Dyspnea and cough symptoms can be expected to persist or even worsen by one-year post infection in those who were hospitalized. Dysphagia and dysphonia symptoms were mild. Non-hospitalized participants tended to have minimal residual symptoms by one year after infection.

Suhuang antitussive capsule ameliorates post-infectious cough in mice through AhR-Nrf2 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Suhuang antitussive capsule (SH capsule), a typical traditional Chinese medicines (TCMs) compound, is widely used for the treatment of post-infectious cough (PIC) in the clinic. Our previous studies have demonstrated that SH capsule possesses significant ameliorative effects on cough variant asthma (CVA), sputum obstruction and airway remodeling.

AIM OF THE STUDY

This study is designed to investigate the ameliorative effects and potential mechanisms of SH capsule on PIC in mice.

MATERIALS AND METHODS

To establish the PIC model, ICR mice were induced by lipopolysaccharide (LPS) (3 mg/kg) once, followed by cigarettes smoke (CS) exposure for 30 min per day for 30 days. Mice were intragastrically (i.g.) administrated with SH capsule at the doses of 3.5, 7, 14 g/kg each day for 2 weeks since the 24th day. The number of coughs, coughs latencies, enzyme-linked immunosorbent assay (ELISA) and histological analysis were used to investigate the effects of SH capsule on PIC mice. Quantitative-polymerase chain reaction (Q-PCR) and western blotting were conducted to evaluate the levels of mRNA and proteins associated with Aryl hydrocarbon receptor (AhR)-NF-E2-related factor 2 (Nrf2) pathway. Superoxide dismutase (SOD), glutathione (GSH) and total antioxidant capacity (T-AOC) assays were performed to evaluate the oxidative stress. A549 cells were used to investigate the ameliorative effects of SH capsule in vitro.

RESULTS

SH capsule effectively diminished the number of coughs and extended coughs latencies in PIC mice. The airway inflammation was alleviated by decreasing the expression levels of inflammatory mediators including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). Moreover, SH capsule dose-dependently activated AhR-Nrf2 pathway and induced the nuclear translocation in vitro and in vivo. Besides, SH capsule significantly increased the levels of SOD, GSH and T-AOC in mice.

CONCLUSION

Our study demonstrates that SH capsule ameliorates airway inflammation-associated PIC in mice through activating AhR-Nrf2 pathway and consequently alleviating inflammatory responses and oxidative stress.

A History of Recurrent Episodes of Prolonged Cough as a Predictive Value for Determining Cough Variant Asthma in a Primary Care Setting

Background

Many patients visit primary care clinics with a complaint of cough. General practitioners (GPs) developed a list of the causative diseases of cough that can produce a patient's symptoms and signs. Then, the patients' medical histories were evaluated to determine whether the diagnosis of cough variant asthma (CVA) or post-infectious cough (PIC) could have been predicted.

Methods

We retrospectively investigated 195 outpatients with a complaint of cough. Medical histories of "recurrent episodes of prolonged cough" and "upper respiratory infection" were obtained during the initial visit. The accuracy of medical histories in predicting CVA and PIC was calculated on the area under the curve (AUC).

Results

Among eligible patients with cough, PIC was diagnosed in 99 patients (50.8%), CVA in 40 patients (20.5%), upper airway cough syndrome in 28 patients (14.4%), and chronic obstructive pulmonary disease in 11 patients (5.6%). Among the patients with CVA and those with PIC, 93% and 12%, respectively, had a history of recurrent episodes of prolonged cough. For the diagnosis of CVA, having a history of recurrent episodes of prolonged cough showed a moderately accurate AUC (0.76, 95% CI: 0.71-0.82). On the other hand, for the diagnosis of PIC, having no history of recurrent episodes of prolonged cough also showed a moderately accurate AUC (0.87, 95% CI: 0.82-0.92).

Conclusion

The medical history of recurrent episodes of prolonged cough is useful for the prediction of CVA as well as PIC.

Gender difference in the association between cough severity and quality of life among patients with postinfectious cough

Background

Despite close link exists between cough severity and quality of life (QoL), whether gender difference is implied in the effect of cough on QoL has not been studied yet. This study primarily aims to investigate whether the association between cough severity and QoL is modified by gender in patients with postinfectious cough.

Methods

Secondary analyses were performed in 180 participants with postinfectious cough in a multisite randomized controlled trial. Baseline demographics, clinical characteristics and score of cough specific quality of life questionnaire (CQLQ) were collected. Linear regression analyses were conducted to examine gender difference in CQLQ score and the association between cough severity and CQLQ score.

Results

Difference between women and men was not significant in CQLQ total score in the unadjusted analysis (P = 0.077). Women had a 2.20-point higher CQLQ total score than men (95% confidence interval (CI) 0.11–4.30; P = 0.039), after adjusting for age, cough duration, cough severity, and clinical center. Gender significantly modified the association between cough severity and CQLQ total score (coefficient 1.80, 95% CI 0.29–3.30; P = 0.020), after adjusting for age, cough duration, and study center. An increase of 1-point in cough severity was associated with a 2.55-point (95% CI 1.16–3.95) increase in CQLQ total score in women versus a 1.26-point (95% CI 0.20–2.31) increase in men (P = 0.020).

Conclusions

Female sex may be associated with worse QoL than men, and women’s QoL may be more significantly impaired as cough symptom deteriorates. Gender difference should be taken into account in the clinical settings and research of cough and cough related QoL.

Trial registration: Chinese Clinical Trial Registry, ChiCTRTRC12002297. Registered 19 June 2012, http://www.chictr.org.cn/abouten.aspx.

The diagnostic utility of the frequency scale for the symptoms of gastroesophageal reflux disease questionnaire (FSSG) for patients with subacute/chronic cough

BACKGROUND

The frequency scale for the symptoms of GERD (FSSG) questionnaire, which originally consists of acid-reflux and dysmotility symptom domains, is a succinct questionnaire to evaluate gastroesophageal reflux disease (GERD) symptoms.

OBJECTIVES

To evaluate the utility of subjective questionnaire of GERD for the diagnosis of GERD-related cough by using FSSG questionnaire.

METHODS

We recruited 256 patients with subacute/chronic cough between April 2012 and March 2018, who were analyzed using FSSG questionnaire and blood eosinophil counts. GERD-related cough was inferred through the presence of classic reflux symptoms including heartburn and/or typical coughing trigger (e.g. phonation, rising, lying, eating, and intake of certain food). The diagnosis was confirmed by response to specific treatments for GERD. Receiver operating characteristic curve analysis was performed to determine the cutoff score for the diagnosis.

RESULTS

One-hundred ten patients (43%) were diagnosed as having GERD-related cough. FSSG questionnaire was relevant for diagnosing GERD-related cough, with the area under the curve (AUC) of 0.70 (p < 0.0001, cutoff score 7 points, sensitivity 75%, specificity 62%). When limited to patients with blood eosinophils of ≤150/μL or those with sputum eosinophils of ≤3%, sensitivity and specificity of the diagnosis was increased, respectively (sensitivity and specificity; 79% and 65% for blood eosinophils and 82% and 68% for sputum eosinophils. p < 0.0001, AUC 0.74 for both).

CONCLUSIONS

The subjective questionnaire of GERD (FSSG) would be helpful in diagnosing GERD-related cough, particularly in patients with low blood or sputum eosinophil counts.

Allergic and Mixed Rhinitis: Diagnosis and Natural Evolution

Chronic rhinitis (CR) is divided into two main categories: allergic rhinitis (AR) and nonallergic rhinitis (NAR). These conditions are more recognizable to an experienced clinician, as they can be more clearly demarcated diagnostically. However, an additional 30% to 50% of patients with CR might have an overlap of NAR and AR, referred to as mixed rhinitis (MR). Progress in elucidating the pathophysiologic mechanisms behind MR and NAR has been made in the past several years, and there are now several guidelines published to assist the clinician in accurately diagnosing AR, NAR, and MR. Clinical history and subjective symptoms can provide clues for differentiating AR from MR and NAR, but allergy testing is recommended to confirm these conditions. Progress in accurately diagnosing patients with CR will be made as studies incorporate subjective (i.e., validated questionnaires such as the irritant index questionnaire (IIQ), medication responsiveness, and quality-of-life tools) and objective (i.e., nasal cytologic testing, nasal provocation, and biomarkers) methods characterizing rhinitis subtypes.

A Cross-sectional Survey of the Clinical Manifestations and Underlying Illness of Cough

AIM

The aim of this study was to identify factors affecting the final diagnosis of cough.

MATERIALS AND METHODS

This study recruited 463 consecutive patients who visited five Japanese general hospitals due to cough from October 2006 to September 2007. Of these, 418 patients (90%) who completed a questionnaire designed to acquire data regarding clinical manifestations of cough were included.

RESULTS

Most patients with bronchial asthma had cough with seasonal variation and wheezing. Patients with gastro esophageal reflux disease suffered from heartburn and cough without daily or seasonal variation. Cough associated with sinobronchial syndrome was only observed in females and was linked to increased sputum. Patients with whooping cough were bothered by cough interrupting sleep and talking. Patients with cardiogenic cough had exertional dyspnea.

CONCLUSION

The specific items on our questionnaire relating to patient characteristics, complications, and triggers of cough, represent useful tools for diagnosing the primary disease producing cough.

Inhaled Corticosteroids and Placebo Treatment Effects in Adult Patients With Cough: A Systematic Review and Meta-analysis

PURPOSE

Inhaled corticosteroids (ICSs) are often considered an empirical therapy in the management of patients with cough. However, ICS responsiveness is difficult to interpret in daily clinical practice, as the improvements may include placebo effects or self-remission. We aimed to evaluate ICS and placebo treatment effects in adult patients with cough.

METHODS

Electronic databases were searched for studies published until June 2018, without language restriction. Randomized controlled trials reporting the effects of ICSs compared with placebo in adult patients with cough were included. Random effects meta-analyses were conducted to estimate the treatment effects. Therapeutic gain was calculated by subtracting the percentage change from baseline in the cough score in the ICS treatment group from that in the placebo treatment group.

RESULTS

A total of 9 studies were identified and 8 studies measuring cough severity outcomes were included for meta-analyses. Therapeutic gain from ICSs ranged from -5.0% to +94.6% across the studies included; however, it did not exceed +22%, except for an outlier reporting very high therapeutic gains (+45.6% to +94.6%, depending on outcomes). Overall ICS treatment effects in cough severity outcomes were small-to-moderate (standardized mean difference [SMD], -0.38; 95% confidence interval [CI], -0.54, -0.23), which were comparable between subacute and chronic coughs. However, pooled placebo treatment effects were very large in subacute cough (SMD, -2.58; 95% CI, -3.03, -2.1), and modest but significant in chronic cough (SMD, -0.46; 95% CI, -0.72, -0.21).

CONCLUSIONS

Overall therapeutic gain from ICSs is small-to-moderate. However, placebo treatment effects of ICS are large in subacute cough, and modest but still significant in chronic cough. These findings indicate the need for careful interpretation of ICS responsiveness in the management of cough patients in the clinic, and also for rigorous patient selection to identify ICS-responders.

Treatments for subacute cough in primary care: systematic review and meta-analyses of randomised clinical trials

BACKGROUND

Subacute cough following a non-specific viral infection lasting 3-8 weeks is common. However, despite many treatment options there are no systematic reviews evaluating these.

AIM

To provide a systematic overview of treatment options and outcomes evaluated in randomised clinical trials (RCTs).

DESIGN AND SETTING

Systematic review and meta-analyses assessing the overall effects of any treatment for subacute cough.

METHOD

The authors systematically searched PubMed/MEDLINE and the Cochrane Central Register of Controlled Trials (last search March 2017) for RCTs in adult patients with subacute cough. The authors considered trials evaluating any outcome of any drug or non-drug treatments, apart from traditional Chinese and Asian medicines. They combined treatment effects on cough-related outcomes in random effects meta-analyses.

RESULTS

Six eligible RCTs including 724 patients were identified. These assessed montelukast, salbutamol plus ipratropium bromide, gelatine, fluticasone propionate, budesonide, and nociception opioid 1 receptor agonist and codeine. Five studies reported effects on various cough severity scores at various timepoints. No treatment option was associated with a clear benefit on cough recovery or other patient-relevant outcomes in any of the studies or in meta-analyses for cough outcomes at 14 days and 28 days. Reported adverse events were rather mild and reported for 14% of patients across all treatments.

CONCLUSION

Evidence on treatment options for subacute cough is weak. There is no treatment showing clear patient-relevant benefits in clinical trials.

Defining the risk factors for acute, subacute and chronic cough: a cross-sectional study in a Finnish adult employee population

OBJECTIVES

Chronic cough is linked to various long-standing risk factors like asthma, chronic rhinitis and oesophageal reflux disease. On the contrary, acute and subacute cough are usually considered to be caused by acute respiratory infections. Little is known about the possible long-standing risk factors for acute and subacute cough. In this study, we have identified the long-standing risk factors for acute, subacute and chronic cough in order to identify the risk factors specifically associated with chronic cough.

DESIGN

A comprehensive 80-item questionnaire was sent via email to the participants.

SETTING

A community-based study to all public service employees of two towns in central Finland.

PARTICIPANTS

There were 13 980 employees, of them 3697 responded (26.4%). Among the responders, there were 199 subjects with current daily acute cough (duration <3 weeks, prevalence 5.4%), 126 subjects with current daily subacute cough (duration 3-8 weeks, prevalence 3.4%) and 267 subjects with current daily chronic cough (duration >8 weeks, prevalence 7.2%).

PRIMARY OUTCOME MEASURES

The risk factors that associated with each cough subtype. The subjects without any cough formed the reference group.

RESULTS

Several risk factors were associated with both short and long cough subtypes namely family history of chronic cough, moisture damage exposure and number of reported somatic symptoms. Furthermore, allergy was associated with acute and subacute cough. Current asthma and chronic rhinitis were associated with subacute and chronic cough. Oesophageal reflux disease and advanced age were associated with chronic cough.

CONCLUSIONS

The specific risk factors for chronic cough were oesophageal reflux disease and advanced age. Acute and subacute cough should not be regarded merely as symptoms of acute respiratory infections but possible manifestations of long-standing risk factors. A new risk factor for all cough types was family history of chronic cough.

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

BACKGROUND

We performed systematic reviews using the population, intervention, comparison, outcome (PICO) format to answer the following key clinical question: Are the CHEST 2006 classifications of acute, subacute and chronic cough and associated management algorithms in adults that were based on durations of cough useful?

METHODS

We used the CHEST Expert Cough Panel's protocol for the systematic reviews and the American College of Chest Physicians (CHEST) methodological guidelines and Grading of Recommendations Assessment, Development, and Evaluation framework. Data from the systematic reviews in conjunction with patient values and preferences and the clinical context were used to form recommendations or suggestions. Delphi methodology was used to obtain the final grading.

RESULTS

With respect to acute cough (< 3 weeks), only three studies met our criteria for quality assessment, and all had a high risk of bias. As predicted by the 2006 CHEST Cough Guidelines, the most common causes were respiratory infections, most likely of viral cause, followed by exacerbations of underlying diseases such as asthma and COPD and pneumonia. The subjects resided on three continents: North America, Europe, and Asia. With respect to subacute cough (duration, 3-8 weeks), only two studies met our criteria for quality assessment, and both had a high risk of bias. As predicted by the 2006 guidelines, the most common causes were postinfectious cough and exacerbation of underlying diseases such as asthma, COPD, and upper airway cough syndrome (UACS). The subjects resided in countries in Asia. With respect to chronic cough (> 8 weeks), 11 studies met our criteria for quality assessment, and all had a high risk of bias. As predicted by the 2006 guidelines, the most common causes were UACS from rhinosinus conditions, asthma, gastroesophageal reflux disease, nonasthmatic eosinophilic bronchitis, combinations of these four conditions, and, less commonly, a variety of miscellaneous conditions and atopic cough in Asian countries. The subjects resided on four continents: North America, South America, Europe, and Asia.

CONCLUSIONS

Although the quality of evidence was low, the published literature since 2006 suggests that CHEST's 2006 Cough Guidelines and management algorithms for acute, subacute, and chronic cough in adults appeared useful in diagnosing and treating patients with cough around the globe. These same algorithms have been updated to reflect the advances in cough management as of 2017.

Clinical Effects and Safety of Zhi Sou San for Cough: A Meta-Analysis of Randomized Trials

Introduction

Zhi Sou San (ZSS), a traditional Chinese prescription, has been widely applied in treating cough. The purpose of this meta-analysis was to evaluate the effectiveness and safety of ZSS for cough.

Methods

We searched relevant articles up to 5 March 2017 in seven electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PubMed, Chinese National Knowledge Infrastructure (CNKI), Cqvip Database (VIP), China Biology Medicine disc (CBM), and Wanfang Data. Randomized controlled trials (RCTs) were eligible, regardless of blinding. The primary outcome was the total effective rate.

Results

Forty-six RCTs with a total of 4007 participants were identified. Compared with western medicine, ZSS significantly improved the total effective rate (OR: 4.45; 95% CI: 3.62–5.47) and the pulmonary function in terms of FEV1 (OR: 0.35; 95% CI: 0.24–0.46) and decreased the adverse reactions (OR: 0.05; 95% CI: 0.02–0.01) and the recurrence rate (OR: 0.30; 95% CI: 0.16–0.57). However, there was no significant improvement in the cough symptom score comparing ZSS with western medicine.

Conclusions

This meta-analysis shows that ZSS has significant additional benefits and relative safety in treating cough. However, more rigorously designed investigations and studies, with large sample sizes, are needed because of the methodological flaws and low quality of the included trials in this meta-analysis.

Association between fractional exhaled nitric oxide and clinical characteristics and outcomes in patients with subacute cough

OBJECTIVES

To investigate the relationships between fractional exhaled nitric oxide (FENO) and clinical characteristics and outcomes in patients with subacute cough.

METHODS

Patients with subacute cough (n = 189) after upper respiratory tract infection were enrolled in this single-center prospective study, and were divided into low-FENO (<25 ppb) and high-FENO groups (≥25 ppb). Empirical therapies (without inhaled or systemic corticosteroids) were prescribed based on clinical experience and follow-up until the disease course reached 8 weeks. FENO values, cough symptom scores (CSS), and Leicester Cough Questionnaire (LCQ) scores were obtained, analyzed, and compared between two groups of patients.

RESULTS

The low-FENO and high-FENO groups comprised 136 and 53 patients, respectively. The multiple regression analysis showed that blood eosinophil count and gender were independent factors for elevated FENO (β = 1.38, 0.25, respectively). LCQ scores, total CSS, and daytime CSS were comparable between the low-FENO and high-FENO groups. The nighttime CSS of the high-FENO group were significantly higher than that of the low-FENO group (P = .03). The CSS and LCQ score were improved in both groups but were comparable between groups after 10 days treatment.

CONCLUSIONS

Patients with subacute cough and high-FENO levels have more severe nocturnal cough than those of patients with low-FENO levels. However, FENO levels do not appear to correlate with the clinical outcomes or treatment response. The significance of FENO in the management of subacute cough needs to be further evaluated, at least in the current empirical treatment without corticosteroids.

Point prevalence and epidemiological characteristics of chronic cough in the general adult population: The Korean National Health and Nutrition Examination Survey 2010-2012

Cough is frequently self-limiting, but may persist longer in certain individuals. Most of previous studies on the epidemiology of chronic cough have only measured period prevalence, and thus have afforded limited information on the burden and natural course. We aimed to investigate the epidemiology of chronic cough by using a point prevalence measure in a large-scale general population.We analyzed cross-sectional data collected from 18,071 adults who participated in the Korean National Health and Nutrition Examination Survey 2010-2012. Presence and duration of current cough was ascertained by structured questionnaires, and cough was classified into acute (<3 weeks), subacute (3-8 weeks), or chronic cough (≥8 weeks). Demographic and clinical parameters were examined in relation to chronic cough.The point prevalences of acute, subacute, and chronic cough were 2.5 ± 0.2%, 0.8 ± 0.1% and 2.6 ± 0.2%, respectively. The proportion of current cough showed a steep decrease after 1 week of duration. However, 2 peaks in the prevalence of current cough were revealed; cough durations of less than 1 week and longer than 1 year were most common (31.1% and 27.7% of current cough, respectively). Subacute and chronic cough were more prevalent in the elderly (≥65 years); the positive associations with older age were independent of other confounders, including current smoking and comorbidities.This is the first report on the epidemiology of cough using a point prevalence measure in a nationally representative population sample. Our findings indicate a high burden of chronic cough among adults with current cough in the community. The dual-peak of cough duration suggested that the pathophysiology of acute and chronic cough may differ. The preponderance of elderly people in the prevalence of chronic cough warrants further investigation. In addition, more sophistication and validation of tools to define chronic cough will help our understanding of the epidemiology.

Chronic cough in Korean adults: a literature review on common comorbidity

Chronic cough is a significant medical condition with high prevalence and a strong negative impact on the quality of life. Cough hypersensitivity is thought to underlie chronic cough, with several environmental and host factors interacting to cause neuronal sensitization and chronicity. Comorbid conditions affecting cough reflex pathways, such as upper airway diseases, asthma, and gastroesophageal reflux, play important roles in chronic cough. However, their prevalence may vary in patients living in different geographical regions or with different ethnicities. We conducted a literature review to examine common comorbidities in Korean adult patients with chronic cough, their clinical implications, and the issues that still need to be addressed in the development of clinical evidence of chronic cough in Korean adult patients.

Curative Effects of Suhuang Zhike Capsule on Postinfectious Cough: A Meta-Analysis of Randomized Trials

Objective. In this paper, we intended to systematically evaluate the efficacy of Suhuang Zhike Capsule (SZC) on postinfectious cough (PIC) in adults (age > 18). Methods. MEDLINE (PubMed), Chinese National Knowledge Infrastructure (CNKI), Cqvip Database (VIP), and Wanfang Database were researched for the randomized controlled trials (RCTs) of SZC for PIC. The search was limited to human studies, using the search keywords or free-text terms “cough,” “post-infectious cough,” “postinfectious cough,” “post-cold cough,” “postviral cough,” “postcold cough,” “Suhuang Zhike capsule,” “Chinese Medicine,” and “randomized clinical trials”. Two reviewers individually extracted data from the included RCTs and then the extracted data were analyzed using Review Manager 5.3 software. Results. Seven RCTs involving 573 patients entered the inclusion criteria. Findings suggested that, compared with western conventional medicine (WCM) and other Chinese medicine, SZC could effectively improve the efficacy rate (OR 2.68, 95%  CI, 1.48–4.84, P = 0.001; OR 4.86, 95%  CI, 1.50–15.73, P = 0.008, separately). Moreover, SZC could also improve the efficacy rate of Chinese medicine symptom (MD −0.74, 95%  CI, −1.46~−0.02, P = 0.04). However, in terms of cough relief time, more evidence is needed to prove that SZC have an earlier antitussive effect (MD −1.31, 95%  CI, −3.06~0.45, P = 0.14). Conclusion. The current evidence shows that SZC is effective in the treatment of PIC in adults and can significantly improve the effective rate of Chinese medicine symptoms.

Eosinophilic airway inflammation is common in subacute cough following acute upper respiratory tract infection

BACKGROUND AND OBJECTIVE

Patients presenting with refractory postinfectious cough may respond to glucocorticosteroids but it is unclear whether airway eosinophilic inflammation exists in those patients. We aimed to determine the airway inflammation and causes of subacute cough following acute upper respiratory tract infection (AURTI).

METHODS

One hundred and sixteen patients with persistent cough lasting 3-8 weeks after upper respiratory tract infection were evaluated with differential cell count in induced sputum, spirometry and methacholine bronchial challenge testing.

RESULTS

In patients with subacute cough, sputum eosinophilia (median 8.5%,3.0-73.0%) was identified in 35 (33.6%) patients, 22 (18.5%) without bronchial hyperresponsiveness (BHR) were diagnosed as non-asthmatic eosinophilic bronchitis (NAEB), 13 (14.3%) of whom with BHR were diagnosed as cough variant asthma (CVA). Cough in patients with sputum eosinophilia improved after treatment with corticosteroids. Compared with postinfectious cough (PIC) and NAEB, CVA had significantly higher median eosinophil count in induced sputum (0.5% vs 7.5% vs 20.0%, P < 0.01). MMEF in CVA was significantly lower than PIC and NAEB (P < 0.05). The common causes of subacute cough following acute upper respiratory tract infection (AURTI) were PIC (37.8%), NAEB (18.5%), CVA (14.3%) and upper airway cough syndrome (UACS) (10.1%). Atopic cough (AC) (5.2%) and gastroesophageal reflux-related cough (GERC) (3.4%) were less common in subacute cough following AURTI, while 9 (7.8%) patients had unexplained cough.

CONCLUSION

Subacute cough following AURTI can be attributed to different entities, eosinophilic airway inflammation is common. Induced sputum should be considered when evaluating patients with subacute cough following acute upper respiratory tract infection.

A traditional herbal medication, Maekmoondong-tang, for cough: A systematic review and meta-analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Maekmoondong-tang (MMDT) is a traditional herbal medication widely used to improve cough in Korea, Japan, and China. It is composed of six herbs (Ophiopogonis Tuber, Pinelliae Tuber, Glycyrrhizae Radix, Zizyphi Fructus, Ginseng Radix, and Oryzae Semen).

AIM OF THE STUDY

This study is aimed to systematically review the relevant randomised controlled trials (RCTs) to determine the effectiveness and safety of MMDT for cough.

MATERIALS AND METHODS

Electronic and hand-searching of 7 databases (Cochrane Library, MEDLINE, EMBASE, OASIS, RISS, CNKI and CiNii) was systematically conducted up to February 2015 for RCTs testing MMDT in patients with cough. The primary outcome was cough symptom improvement using cough diary, visual analog scale, or response rate. Risk of bias of the included trials was evaluated with the Cochrane risk of bias assessment tool. The dichotomous data were pooled to obtain a risk ratio (RR) of cough persisting after treatment, with 95% confidence intervals (CI).

RESULTS

Nine RCTs involving 2453 participants were included. The methodological quality was largely poor for a majority of the studies. MMDT reduced the severity of cough by 74% compared with the conventional antitussive medications in various conditions (n=1145; RR of cough persisting after treatment=0.26; 95% CI, 0.19-0.34, I(2)=0%). The addition of MMDT to conventional medication in patients with postinfectious cough significantly alleviated symptoms up to day 5 but the effect was not maintained one week afterwards. For other diseases/conditions including chronic obstructive pulmonary disease, lung cancer surgery, and asthma, the evidence is inconsistent for MMDT/mMMDT for cough. Adverse events appear to be rare but the reporting was poor.

CONCLUSIONS

The current evidence from our systematic review and meta-analysis on MMDT for cough is inconclusive and we propose that rigorously designed, placebo-controlled trials of MMDT should be conducted to establish its place in management of cough.

The duration of cough in patients with H1N1 influenza

BACKGROUND

Cough is one of common symptoms of influenza, the cough duration and prevalence of postinfectious cough (PIC) after viral upper respiratory tract infection has not been well described.

OBJECTIVES

We aim to investigate the duration of cough and prevalence of PIC and its relation with acute symptoms, airway inflammation and cough sensitivity in patients with H1N1 influenza.

METHODS

Patients with acute symptoms of H1N1 influenza were enrolled and followed up until cough relived. Spirometry, induced sputum test, capsaicin challenge test were conducted in patients with PIC. Cough sensitivity was presented as logarithm of provocative concentration inducing five or more coughs (logC5).

RESULTS

A total of 141 cases with H1N1 influenza were enrolled. In patients with H1N1 influenza, 97.2% of them complained cough. The duration of cough was as following: <1 week (73.0%); 1-2 weeks (7.8%); 2-3 weeks (7.8%); ≥3 weeks (8.5%). Twelve (8.5%) patients had cough lasting more than 3 weeks (PIC), 4 (2.8%) patients developed chronic cough (>8 weeks). Acute symptoms, spirometry, bronchial responsiveness and sputum differential cell count were similar between patients with PIC and those without PIC, however, there was a higher prevalence of previous PIC (58.3% vs 14.7%, P < 0.05) and elevated cough sensitivity (lgC5: 1.18 ± 0.58 vs 2.73 ± 0.33, P < 0.01) in patients with PIC as compared with the patients without PIC.

CONCLUSIONS

Acute cough is common in patients with H1N1 PIC, only a few of patients develop chronic cough. Acute symptoms cannot predict PIC which is related with previous PIC and increased cough sensitivity.

Efficacy and safety of Qing-Feng-Gan-Ke Granules in patients with postinfectious cough: study protocol of a novel-design phase III placebo-controlled, double-blind randomized trial

BACKGROUND

Postinfectious cough (PIC) is a common condition that affects millions of people worldwide every year. There is Western medicine for this condition but the treatment effect is often incomplete. Traditional Chinese medicine (TCM) has been increasingly prescribed for patients with PIC. Preliminary trials on Qing-Feng-Gan-Ke-Granules (QFGKG) conveyed promising results in treating PIC. This protocol describes an ongoing phase III randomized controlled clinical trial, designed according to a novel methodology of "one study, one primary outcome", with the objective of evaluating the efficacy and safety of QFGKG in patients suffering from PIC.

METHODS/DESIGN

This is a multicenter, phase III, randomized, double-blind, parallel-group, placebo-controlled clinical trial, comprising two simultaneously conducted study parts, part A and part B, intending to investigate two primary outcomes, i.e. time to cough resolution and cough symptom score, respectively. A total of 480 patients, aged 18 to 65 years, who complain of an ongoing persistent cough that has been lasting ≥ 3 weeks, will be recruited from six participating sites and then randomized to receive QFGKG 12.0 g twice daily or placebo 12.0 g twice daily. Each part will enroll 240 patients, with 180 patients being allocated to the QFGKG group and 60 to the placebo group.

DISCUSSION

Although traditional Chinese medicine is a structured intervention that has shown some promise in treating persistent cough, existing unconvincing evidence has noted limitations. This is a rare well-designed and rigorously-controlled, randomized, double-blind trial to evaluate the effects and safety of a Chinese herbal medicine in patients with postinfectious cough, providing tangible benefits for clinical research. Results of this trial are inclined to be conjectured as more truthful by implementing separate study parts that specifically estimate exclusive primary outcome. It will not only provide robust clinical evidence on the efficacy and safety of QFGKG for postinfectious cough, but will also provide a critical piece of information on the availability and superiority of a novel methodology for future clinical trials. The current trial is ongoing with recruitment of the predetermined number of patients being in progress.

TRIAL REGISTRATION

The two parts of this trial were separately registered with the Chinese Clinical Trial Registry: ChiCTR-TRC-13003278 (part A); and ChiCTR-TRC-13003337 (part B).

The efficacy of QingfengGanke granule in treating postinfectious cough in pathogenic wind invading lungs syndrome: a multicenter, randomized, double-blind, placebo-controlled trial

BACKGROUND

Postinfectious cough (PIC) significantly affects cough-related quality of life but still lacks effective treatments. This study aims to investigate the efficacy of QingfengGanke granule (QFGKG) in treating PIC induced by pathogenic wind invading lungs syndrome.

METHODS

A multicenter, randomized, double-blind, placebo-controlled clinical trial was conducted. A total of 180 eligible participants were randomly (1:1:1) assigned to group A (QFGKG 6 g plus QFGKG-matched placebo 6 g), group B (QFGKG 12 g), and group C (QFGKG-matched placebo 12 g). All herbal medications were orally administered twice daily for 10 consecutive days. The primary outcome was time to cough resolution, and secondary outcomes included time to cough alleviation, mean changes in cough symptom score (CSS), visual analogue scale (VAS) score, cough-specific quality of life questionnaire (CQLQ) score, and traditional Chinese medicine (TCM) syndrome score from baseline to Day 10, as well as adverse events.

RESULTS

A total of 173 participants were included in the efficacy and safety analyses (group A, n = 57; group B, n = 57; group C, n = 59). The median time to cough resolution in groups A, B, and C was more than 10 days, 8 days, and more than 10 days, respectively (P < 0.0001), and the median time to cough alleviation was 4, 4, and 6 days, respectively (P < 0.0001). Compared with the placebo condition, groups A and B showed significantly greater improvements in CSS (P = 0.0005, P < 0.0001, respectively), VAS (P = 0.0002, P < 0.0001, respectively), CQLQ (P = 0.0258, P = 0.0003, respectively), and TCM syndrome (P = 0.0031, P < 0.0001, respectively). The time to cough resolution was faster in group B compared with group A (P = 0.0091). The adverse event profiles were comparable among the three groups.

CONCLUSION

QingfengGanke granule is efficacious in the treatment of PIC induced by pathogenic wind invading lungs syndrome.

Fractional exhaled nitric oxide: comparison between portable devices and correlation with sputum eosinophils

This study was performed to compare the 2 different portable devices measuring fractional exhaled nitric oxide (FeNO) and to see the correlation between FeNO and induced sputum eosinophil count (ISE). Forty consecutive subjects clinically suspected to have asthma underwent FeNO measurement by NIOX-MINO® and NObreath® concurrently. All also had induced sputum analysis, methacholine provocation test or bronchodilator response test, and spin prick test. Agreement between the 2 devices was evaluated. The correlation between FeNO and ISE was assessed, as well as the cut-off level of FeNO to identify ISE ≥3%. The intraclass correlation coefficient (ICC) between FeNO levels measured by NIOX-MINO® (FeNO_NIOX-MINO) and NObreath® (FeNON_Obreath) was 0.972 with 95% confidence interval of 0.948-0.985. The 95% limits of agreement were -28.9 to 19.9 ppb. The correlation coefficient between ISE and FeNO_NIOX-MINO was 0.733 (P<0.001), and 0.751 between ISE and FeNO_NObreath (P<0.001). The ROC curve found that the FeNO_NIOXMINO of 37.5 ppb and the FeNO_NObreath of 36.5 ppb identified ISE ≥3% with 90% sensitivity and 81% specificity. Age, sex, body mass index, smoking history, atopy, and the presence of asthma did not affect the FeNO level and its correlation with ISE. The NIOX-MINO ® and NObreath® agree with each other to a high degree. Both devices showed close correlation with ISE with similar cut-off value in identifying ISE ≥3%.

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.

Developing and emerging clinical asthma phenotypes

For more than a century, clinicians have attempted to subdivide asthma into different phenotypes based on triggers that cause asthma attacks, the course of the disease, or the prognosis. The first phenotypes that were described included allergic asthma, intrinsic or nonallergic asthma, infectious asthma, and aspirin-exacerbated asthma. These phenotypes are being reviewed elsewhere in this issue of the journal. The present article focuses on developing and emerging clinical asthma phenotypes. First, asthma phenotypes that are associated with environmental exposures (occupational agents, cigarette smoke, air pollution, cold dry air); second, asthma phenotypes that are associated with specific symptoms or clinical characteristics (cough, obesity, adult onset of disease); and third, asthma phenotypes that are based on biomarkers. This latter approach is the most promising because it attempts to identify asthma phenotypes with different underlying mechanisms so that therapies can be better targeted toward disease-specific features and disease outcomes can be improved.

Efficacy of procaterol combined with inhaled budesonide for treatment of cough-variant asthma

BACKGROUND AND OBJECTIVE

Procaterol, a selective, short-acting beta-2 adrenoceptor agonist, is effective in treating 'classical' asthma, but its efficacy for cough-variant asthma (CVA) is unknown. We evaluated the efficacy and safety of procaterol combined with budesonide for CVA.

METHODS

A prospective, randomized, double-blind, placebo-controlled, multicenter trial in China was conducted. One hundred and fifty-nine patients diagnosed with CVA (aged 18-75 years) were randomly divided into two groups to receive twice daily for 8 weeks, inhaled budesonide 100 μg plus either oral procaterol 25 μg or placebo. Primary and secondary efficacy variables were cough symptom severity scores and Leicester Cough Questionnaire (LCQ) life quality scores. Adverse events were also assessed.

RESULTS

The budesonide/placebo and budesonide/procaterol groups contained 80 and 78 participants (one excluded for later diagnosis of eosinophilic bronchitis), respectively, with similar baseline characteristics. Daily cough score declined during treatment in both groups and was lower in the budesonide/procaterol group at 8 (0.44 vs 0.73) and 10 (0.36 vs 0.69) weeks (P < 0.05). Compared with the budesonide/placebo group, the proportion of patients with a reduction of 3 points or greater (66% vs 42%) and that of patients scoring 0 points (63% vs 51%) was higher in the budesonide/procaterol group for daily cough scores (P < 0.05). At 8 weeks, LCQ score improvement was superior in the budesonide/procaterol group (38.94 ± 19.24 vs 32.71 ± 18.92; P < 0.05).

CONCLUSION

Procaterol combined with budesonide was well tolerated and effective at improving cough symptoms and quality of life in patients with CVA.

Whooping cough in school age children presenting with persistent cough in UK primary care after introduction of the preschool pertussis booster vaccination: prospective cohort study

OBJECTIVE

To estimate the prevalence and clinical severity of whooping cough (pertussis) in school age children presenting with persistent cough in primary care since the introduction and implementation of the preschool pertussis booster vaccination.

DESIGN

Prospective cohort study (November 2010 to December 2012).

SETTING

General practices in Thames Valley, UK.

PARTICIPANTS

279 children aged 5 to 15 years who presented in primary care with a persistent cough of two to eight weeks' duration. Exclusion criteria were cough likely to be caused by a serious underlying medical condition, known immunodeficiency or immunocompromise, participation in another clinical research study, and preschool pertussis booster vaccination received less than one year previously.

MAIN OUTCOME MEASURES

Evidence of recent pertussis infection based on an oral fluid anti-pertussis toxin IgG titre of at least 70 arbitrary units. Cough frequency was measured in six children with laboratory confirmed pertussis.

RESULTS

56 (20%, 95% confidence interval 16% to 25%) children had evidence of recent pertussis infection, including 39 (18%, 13% to 24%) of 215 children who had been fully vaccinated. The risk of pertussis was more than three times higher (21/53; 40%, 26% to 54%) in children who had received the preschool pertussis booster vaccination seven years or more previously than in those who had received it less than seven years previously (20/171; 12%, 7% to 17%). The risk of pertussis was similar between children who received five and three component preschool pertussis booster vaccines (risk ratio for five component vaccine 1.14, 0.64 to 2.03). Four of six children in whom cough frequency was measured coughed more than 400 times in 24 hours.

CONCLUSIONS

Pertussis can still be found in a fifth of school age children who present in primary care with persistent cough and can cause clinically significant cough in fully vaccinated children. These findings will help to inform consideration of the need for an adolescent pertussis booster vaccination in the United Kingdom.

STUDY REGISTRATION

UK Clinical Research Network portfolio ID 8361.

A novel diagnostic algorithm for chronic and subacute cough

BACKGROUND

Cough remains the most common reason for patients to seek medical attention. We practised a novel diagnostic algorithm for chronic and subacute cough.

METHODS

Chronic and subacute cough patients with normal chest X-ray results and without respiratory tract infections in the preceding eight weeks were recruited. The patients were divided into two groups: Group A, patients with typical symptoms and signs of postnasal drip syndrome (PNDS), asthma syndromes (AS) and gastroesophageal reflux disease (GERD); Group B, patients without the typical symptoms and signs. The two groups received targeted or sequential empirical trials of therapy according to the algorithm.

RESULTS

Among the 524 patients available for analysis in Groups A and B, 436 (83.6%) were diagnosed to have PNDS (34.2%), AS (44.5%) and/or GERD (10.1%), among which 26 had two causes (6.0%) and 6 had three causes (1.4%). After empirical trials of therapy, 81.5% of the patients were diagnosed. The mean time for diagnosis was considerably shorter in Group A (13.1 ± 5.6 d) than in Group B (23.4 ± 7.2 d) (p < 0.01). The diagnosis rate of the first trial in Group A (54.1%) was significantly higher than that in Group B (28.6%, p < 0.01).

CONCLUSIONS

The proposed algorithm is a promising and practical approach to diagnose chronic and subacute cough.

Chest radiography in supporting the diagnosis of asthma in children with persistent cough

OBJECTIVE

To establish whether chest radiographic findings suggestive of lower airway obstruction (LAO) disease support the diagnosis of asthma in pediatric patients with persistent cough in an outpatient setting.

METHODS

180 patient charts were reviewed. The patients were children aged 1 to 18 years referred over a 3-year period to a pediatric pulmonary subspecialty clinic for evaluation of cough lasting ≥ 4 weeks. Chest radiographic images obtained after the initial evaluation of 90 patients diagnosed with cough-variant asthma and 90 patients diagnosed with persistent cough from nonasthma origins were compared with radiologic findings of a control group consisting of patients with a positive tuberculin skin test and no respiratory symptoms. Increased peribronchial markings/peribronchial cuffing and hyperinflation were considered radiographically suggestive findings of LAO disease.

RESULTS

Children diagnosed with cough-variant asthma at the initial evaluation had higher rates of chest radiographic findings suggestive of LAO disease (30.00%) than children with persistent cough from other causes (17.80%) or those with a positive tuberculin skin test and no respiratory symptoms (8.16%) (overall P value = 0.0063). They also had higher rates of spirometry abnormalities suggestive of an LAO defect. Children with chest radiographic findings suggestive of LAO disease were found to be younger than those with normal chest radiographic findings (5.0 ± 2.7 years vs 8.6 ± 4.7 years; P < 0.0001).

CONCLUSION

This study suggests that chest radiographic findings indicative of an LAO in correlation with the clinical presentation can support the diagnostic suspicion of asthma, especially in younger children unable to perform spirometry.

Changing the paradigm for cough: does 'cough hypersensitivity' aid our understanding?

Chronic cough is a common reason for patients to seek medication attention. Over the last few decades, we have experienced significant clinical success by applying the paradigm of 'evaluating and treating the causes for chronic cough'. However, we still ask ourselves 'what underlies chronic cough. Indeed in a considerable proportion of patients cough is idiopathic, or unexplained despite vigorous evaluation. Commonly associated conditions such as rhinitis, eosinophilic bronchitis, asthma, or gastroesophageal acidic reflux may not be fundamental to cough, and thus may be triggers rather than causes. The cardinal feature of chronic cough is persistent upregulation the cough reflex, which may be driven by complex interactions between biologic, neurologic, immunologic, genetic, comorbid, and environmental factors. We suggest the new paradigm 'cough hypersensitivity syndrome' should finally bring us further advances in understanding and management of chronic cough.

Montelukast for postinfectious cough in adults: a double-blind randomised placebo-controlled trial

BACKGROUND

Postinfectious cough is common in primary care, but has no proven effective treatments. Cysteinyl leukotrienes are involved in the pathogenesis of postinfectious cough and whooping cough (pertussis). We investigated the effectiveness of montelukast, a cysteinyl leukotriene receptor antagonist, in the treatment of postinfectious cough.

METHODS

In this randomised, placebo-controlled trial, non-smoking adults aged 16-49 years with postinfectious cough of 2-8 weeks' duration were recruited from 25 general practices in England. Patients were tested for pertussis (oral fluid anti-pertussis toxin IgG) and randomly assigned (1:1) to montelukast 10 mg daily or image-matched placebo for 2 weeks. Patients chose whether to continue study drug for another 2 weeks. The randomisation sequence was computer-generated and stratified by general practice. Patients, health-care professionals, and researchers were masked to treatment allocation. Effectiveness was assessed with the Leicester Cough Questionnaire to measure changes in cough-specific quality of life; the primary outcomes were changes in total score between baseline and two follow-up stages (2 weeks and 4 weeks). The primary analysis was by intention to treat with imputation by last observation carried forward. Recruitment closed on Sept 21, 2012, and follow-up has been completed. This trial is registered with EudraCT (2010-019647-19), UKCRN Portfolio (ID 8360), and ClinicalTrials.gov (NCT01279668).

FINDINGS

From April 13, 2011, to Sept 21, 2012, we randomly assigned 276 patients to montelukast (n=137) or placebo (n=139). 70 (25%) patients had laboratory-confirmed pertussis. Improvements in cough-specific quality of life occurred in both groups after 2 weeks (montelukast: mean 2·7, 95% CI 2·2-3·3; placebo: 3·6, 2·9-4·3), but the difference between groups did not meet the minimum clinically important difference of 1·3 (mean difference -0·9, -1·7 to -0·04, p=0·04). This difference was not statistically significant in any sensitivity analyses. After 2 weeks, 192 of 259 participants from whom data were available elected to continue study drug (99 [77%] of 129 participants on montelukast; 93 [72%] of 130 on placebo). After 4 weeks, there were no significant between-group differences in cough-specific quality of life improvement (montelukast: 5·2, 4·5-5·9; placebo: 5·9, 5·1-6·7; mean difference -0·5, -1·5 to 0·6, p=0·38) or adverse event rates (21 (15%) of 137 patients on montelukast reported one or more adverse events; 31 (22%) of 139 on placebo; p=0·14). The most common adverse events reported were increased mucus production (montelukast, n=6; placebo, n=2), gastrointestinal disturbance (montelukast, n=3; placebo, n=5), and headache (montelukast, n=2; placebo, n=6). One serious adverse event was reported (placebo, n=1), which was unrelated to study drug (shortness of breath and throat tightness after severe coughing bouts).

INTERPRETATION

Montelukast is not an effective treatment for postinfectious cough. However, the burden of postinfectious cough in primary care is high, making it an ideal setting for future antitussive treatment trials.

FUNDING

National Institute for Health Research School for Primary Care Research, UK.

Chinese herbal medicine for postinfectious cough: a systematic review of randomized controlled trials

Chinese herbal medicine has been commonly used in the treatment of postinfectious cough. The aim of this review is to systematically evaluate the efficacy and safety of Chinese herbal medicine for postinfectious cough. An extensive search for RCTs was performed using multiple electronic databases, supplemented with a manual search. All studies included were confirmed with specific inclusion criteria. Methodological quality of each study was examined according to the Cochrane risk of bias assessment. Quality of evidence was evaluated using rating approach developed by GRADE working group. The literature search yielded 352 results, of which 12 RCTs satisfied the inclusion criteria, offering moderate-to-high levels of evidence. Methodological quality was considered high in three trials, while in the other nine studies the unclear risk of bias was in the majority. Findings suggested that, compared with western conventional medicine or placebo, Chinese herbal medicine could effectively improve core symptoms of postinfectious cough, act better and have earlier antitussive effect, and enhance patients' quality of life. No serious adverse event was reported.

Potential masking of airway eosinophilic inflammation by combination therapy in asthma

Purpose

Long-acting β₂ agonists (LABA) may mask ongoing bronchial inflammation, leaving asthmatic patients at greater risk of severe complications. The aim of this study was to compare the effect of combination therapy using low-dose inhaled corticosteroids (ICS) plus LABA on airway inflammation in asthma to the effect of medium-dose ICS alone.

Methods

Twenty-four patients with asthma not controlled by low-dose (400 µg per day) budesonide alone were enrolled in this prospective crossover study. Patients were randomized into 2 treatment phases: one receiving medium-dose (800 µg per day) budesonide (ICS phase), and the other receiving a combination therapy of low-dose budesonide/formoterol (360 µg/9 µg per day) delivered by a single inhaler (LABA phase). Each treatment phase lasted for 6 week, after which patients were crossed over. Asthma symptoms, lung function, and airway inflammation were compared between the 2 phases.

Results

Twenty-three patients completed the study; adequate sputum samples were collected from 17 patients. Asthma symptoms and lung function remained similar between the 2 phases. However, the mean sputum eosinophil percentage was higher in the LABA phase than in the ICS phase (5.07±3.82% vs. 1.02±1.70%; P<0.01). Sputum eosinophilia (≥3%) was more frequently observed in the LABA phase than in the ICS phase (six vs. two).

Conclusion

Addition of LABA may mask airway eosinophilic inflammation in asthmatic patients whose symptoms are not controlled with low-dose ICS.

Chronic cough in children

The management of chronic cough, a common complaint in children, is challenging for most health care professionals. Millions of dollars are spent every year on unnecessary testing and treatment. A rational approach based on a detailed interview and a thorough physical examination guides further intervention and management. Inexpensive and simple homemade syrups based on dark honey have proved to be an effective measure when dealing with cough in children.

Epidemiology of cough in relation to China

Cough is one of the most common complaints for which patients seek medical attention. Misdiagnosis and mistreatment of cough exist commonly in China. The prevalence of acute cough caused by upper airway infection fluctuates between 9% and 64% in the community, for chronic cough, the prevalence >10% in most surveys, ranging from 7.2%-33%. The common causes of chronic cough are upper airway cough syndrome (previously called as post nasal drip syndrome [PNDS]), cough variant asthma (CVA), gastroesophageal reflux related cough (GERD) and eosinophilic bronchitis (EB). There is a regional discrepancy regarding the prevalence of common causes of cough and distribution of gender among China, UK, USA, the most common cause of chronic cough in China are CVA, followed by UACS, EB and atopic cough (AC), the male is almost equal to female in numbers in China. The risk factors for cough includes cold air, smoking, environmental pollutants, noxious substances and allergens, and unreasonable diet habits.

The difficult coughing child: prolonged acute cough in children

Cough is one of the most common symptoms that patients bring to the attention of primary care clinicians. Cough can be designated as acute (<3 weeks in duration), prolonged acute cough (3 to 8 weeks in duration) or chronic (> 8 weeks in duration). The use of the term ‘prolonged acute cough’ in a cough guideline allows a period of natural resolution to occur before further investigations are warranted. The common causes are in children with post viral or pertussis like illnesses causing the cough. Persistent bacterial bronchitis typically occurs when an initial dry acute cough due to a viral infection becomes a prolonged wet cough remaining long after the febrile illness has resolved. This cough responds to a completed course of appropriate antibiotics.

Inhaled corticosteroids for subacute and chronic cough in adults

BACKGROUND

Persistent cough is a common clinical problem. Despite thorough investigation and empirical management, a considerable proportion of those people with subacute and chronic cough have unexplained cough, for which treatment options are limited. While current guidelines recommend inhaled corticosteroids (ICS), the research evidence for this intervention is conflicting.

OBJECTIVES

To assess the effects of ICS for subacute and chronic cough in adults.

SEARCH METHODS

We searched the Cochrane Airways Group Register of Trials, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and ClinicalTrials.gov in December 2012 and conducted handsearches.

SELECTION CRITERIA

Two authors independently assessed all potentially relevant trials. All published and unpublished randomised comparisons of ICS versus placebo in adults with subacute or chronic cough were included. Participants with known chronic respiratory disease and asthma were excluded. Studies of cough-variant asthma and eosinophilic bronchitis were eligible.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data pertaining to pre-defined outcomes. The primary outcome was the proportion of participants with clinical cure or significant improvement (over 70% reduction in cough severity measure) at follow up (clinical success). The secondary outcomes included proportion of participants with clinical cure or over 50% reduction in cough severity measure at follow up, mean change in cough severity measures, complications of cough, biomarkers of inflammation and adverse effects. We requested additional data from study authors.

MAIN RESULTS

Eight primary studies, including 570 participants, were included. The overall methodological quality of studies was good. Significant clinical heterogeneity resulting from differences in participants and interventions, as well as variation in outcome measures, limited the validity of comparisons between studies for most outcomes. Data for the primary outcome of clinical cure or significant (> 70%) improvement were available for only three studies, which were too heterogeneous to pool. Similarly, heterogeneity in study characteristics limited the validity of meta-analysis for the secondary outcomes of proportion of participants with clinical cure or over 50% reduction in cough severity measure and clinical cure. One parallel group trial of predominantly chronic cough with 'cough-variant asthma' identified a significant treatment effect and contributed to the majority of statistical heterogeneity for these outcomes. While ICS treatment resulted in a mean decrease in cough score of 0.34 standard deviations (SMD -0.34; 95% CI -0.56 to -0.13; 346 participants), the quality of evidence was low. Heterogeneity also prevented meta-analysis for the outcome of mean change in visual analogue scale score. Meta-analysis was not possible for the outcomes of pulmonary function, complications of cough or biomarkers of inflammation due to insufficient data. There was moderate quality evidence that treatment with ICS did not significantly increase the odds of experiencing an adverse event (OR 1.67; 95% CI 0.92 to 3.04).

AUTHORS' CONCLUSIONS

The studies were highly heterogeneous and results were inconsistent. Heterogeneity in study design needs to be addressed in future research in order to test the efficacy of this intervention. International cough guidelines recommend that a trial of ICS should only be considered in patients after thorough evaluation including chest X-ray and consideration of spirometry and other appropriate investigations.

Inhaled corticosteroids for subacute cough in children

BACKGROUND

Cough is the most common symptom presenting to primary healthcare services. Cough in children is associated with significant morbidity for both children and their parents. While inhaled corticosteroids (ICS) can potentially reduce cough associated with airway inflammation and airway hyper-reactivity, use of ICS in children is not without potential adverse effects. Therefore, it would be beneficial to clinical practice to evaluate the evidence for the efficacy of ICS in reducing the severity of cough in children with subacute cough (defined as cough duration of two to four weeks) systematically.

OBJECTIVES

To evaluate the efficacy of ICS in reducing the severity of cough in children with subacute cough.

SEARCH METHODS

The Cochrane Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Specialised Register, MEDLINE, EMBASE, review articles and reference lists of relevant articles were searched. The latest searches were performed in November 2011.

SELECTION CRITERIA

All randomised controlled trials (RCTs) comparing ICS with a control group in children with subacute cough were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Search results were reviewed against pre-determined criteria for inclusion. Two sets of review authors independently selected, extracted and assessed the data for inclusion. Study authors were contacted for further information where required. Data were analysed as 'intention to treat'.

MAIN RESULTS

The search identified 1178 potentially relevant titles; however, there were no published studies that were specifically designed to answer this question. Two studies met criteria for inclusion in the review and 98 children were included in the meta-analysis. There was no significant difference between groups in the proportion of children 'not cured' at follow-up (primary outcome measure), with a pooled odds ratio (OR) of 0.61 (95% confidence interval (CI) 0.24 to 1.55). However, the included studies were limited in their ability to answer the review question by the fact that all participants were infants, post acute bronchiolitis illness, and cough duration at the start of study medication was ill-defined.

AUTHORS' CONCLUSIONS

There is currently no evidence to support the use of ICS for treatment of subacute cough in children. However, this systematic review is limited by the small number of studies available for analysis and the size, quality and design of these studies. Further well-designed RCTs are required to support or refute the efficacy of treatment with ICS in children with subacute cough.

Mycoplasma pneumoniae and respiratory virus infections in children with persistent cough in England: a retrospective analysis

BACKGROUND

Persistent cough following an acute respiratory tract infection is common in children, but clinicians may find it difficult to give accurate prognostic information on likely duration of cough without a microbiologic diagnosis. This study estimates the prevalence of Mycoplasma pneumoniae (Mp) and assesses the prognostic value of detecting Mp and respiratory viruses in children with persistent cough.

METHODS

We retrospectively analyzed blood samples, nasopharyngeal aspirates (NPAs), and cough duration data from 179 children with persistent cough lasting 14 days or longer. Of these children, 37% had serologically confirmed Bordetella pertussis (pertussis). We detected Mp by polymerase chain reaction of NPAs and IgM serology, and respiratory viruses (human rhinoviruses, influenza viruses, respiratory syncytial viruses, and human metapneumovirus) by polymerase chain reaction of NPAs. We used Kaplan-Meier analyses to calculate median cough durations with 95% confidence intervals (CIs).

RESULTS

We detected Mp in 22 of 170 children with sufficient blood and/or NPAs (12.9%, 95% CI: 8.7-18.8). Cough duration in children with positive Mp serology (median: 39 days, 95% CI: 24-54) was significantly shorter than in children with positive pertussis serology (median: 118 days, 95% CI: 82-154, P < 0.001). The presence of respiratory viruses did not significantly lengthen cough duration in children with pertussis (median: 154 days, 95% CI: 74-234, P = 0.810). Only 3 children had both Mp and respiratory virus infections.

CONCLUSIONS

Mp is an important infection in children with persistent cough and is associated with a significantly shorter duration of cough than pertussis. However, detecting respiratory viruses does not add prognostic value in children with pertussis.