Epidemiology of cough

Systematic review and meta-analysis: proton pump inhibitors slightly decrease the severity of chronic cough

The Montreal consensus recognizes chronic cough as an extra-esophageal manifestation of gastroesophageal reflux disease. We performed a meta-analysis to assess the effects of acid-suppressive medications in adults with non-specific chronic cough. The protocol was registered on PROSPERO (CRD42022368769). Placebo-controlled randomized trials evaluating the impact of acid-suppressive medications on persistent cough were included. The systematic search was performed on the 1st of November 2022 in three databases. A random-effects model was used for the calculations. The effect size was the standardized mean difference (SMD) with 95% confidence interval (CI). A total number of 11 double-blinded placebo-controlled randomized trials were included in the meta-analysis. Data showed that compared to placebo, PPIs decreased the severity of cough (SMD 0.33; CI 0.05; 0.61). Therapeutic response was not different in patients with non-specific chronic cough only, compared to those with laryngopharyngeal reflux. Prolonged treatment durations did not result in greater symptomatic improvement, with SMD 0.33 (CI - 0.22; 0.88), 0.31 (CI - 1.74; 2.35), 0.32 (CI - 0.29; 0.93) and 0.34 (CI - 0.16; 0.85), following 4, 6, 8 and 12 weeks of treatment, respectively. The pooled analysis of the improvement in quality of life with PPIs found an SMD of 0.39 (CI - 0.51; 1.29). PPIs mildly decrease the severity of non-specific chronic cough, irrespective of treatment duration.

Consensus goals and standards for specialist cough clinics: the NEUROCOUGH international Delphi study

Background

Current guidelines on the management of chronic cough do not provide recommendations for the operation of specialist cough clinics. The objective of the present study was to develop expert consensus on goals and standard procedures for specialist cough clinics.

Methods

We undertook a modified Delphi process, whereby initial statements proposed by experts were categorised and presented back to panellists over two ranking rounds using an 11-point Likert scale to identify consensus.

Results

An international panel of 57 experts from 19 countries participated, with consensus reached on 15 out of 16 statements, covering the aims, roles and standard procedures of specialist cough clinics. Panellists agreed that specialist cough clinics offer optimal care for patients with chronic cough. They also agreed that history taking should enquire as to cough triggers, cough severity rating scales should be routinely used, and a minimum of chest radiography, spirometry and measurements of type 2 inflammatory markers should be undertaken in newly referred patients. The importance of specialist cough clinics in promoting clinical research and cough specialty training was acknowledged. Variability in healthcare resources and clinical needs between geographical regions was noted.

Conclusions

The Delphi exercise provides a platform and guidance for both established cough clinics and those in planning stages.

Introduction of a systematic examination framework for chronic cough: a before-after cohort study in a clinical setting

Cough is a condition that can be caused by several different mechanisms. There are numerous guidelines for diagnosing the cause of cough, yet the effect of a well-constructed examination framework has not been investigated. At the Department of Internal Medicine, Lillebaelt Hospital, Vejle, a systematic examination framework for diagnosing cough was introduced. Two hundred consecutive patients referred to the pulmonary outpatient clinic with cough were included. The first 100 patients (Group 1) were included before implementation of the examination framework and diagnosed as usual. The next 100 patients (Group 2) were examined using the systematic framework. The primary endpoint was the number of appointments required to establish a diagnosis. A multivariable Poisson regression was performed, adjusting for age, sex, body mass index, pulmonary function (FEV1/FVC), duration of cough, and smoking status. A diagnosis was established within 1-2 visits in 47% in Group 1 compared to 83% in Group 2. When adjusting for confounders, fewer appointments was required to establish a diagnosis in Group 2 (Incidence rate ratio = 0.713 (95% confidence interval: 0.592-0.859), P = 0.000). Using a systematic examination framework for diagnosing cough may reduce the number of appointments required to establish a diagnosis, seemingly without compromising the diagnostic outcome.

A register-based study: cough - a frequent phenomenon in the adult population

Background

Chronic cough, more than 8 weeks, can either be without co-morbidity called unexplained chronic cough (UCC) or with co-morbidity called refractory chronic cough (RCC). Using datasets from the Danish National Prescription Registry (Prescription Registry) and Danish National Patient Registry (Patient Registry) we wanted to investigate the prevalence and factors of importance of cough in a Nationwide registry.

Material and methods

Inclusion criteria were patients 18–90 years with at least one final cough diagnosis (ICD-10 DR05/DR059) in Patient registry or patients who have redeemed ≥2 prescriptions for relevant cough-medication within a 90-day harvest in the Prescription registry from 2008 to 2017. To validate this study’s chosen proxy on chronic cough an analysis of the Patient registry sub-population with a contact of ≥8 weeks and then final diagnosis code DR05/DR059 was also performed. The population was divided into UCC and RCC.

Results

Of the 104,216 patients from the Prescription registry, 52,727 were classified as having UCC and 51,489 were classified with RCC. From the Patient registry 34,260 were included, of whom 12,278 had UCC and 21,982 had RCC. Cough were frequently found among females (p < 0.0001). Both genders were around 2 years older in RCC than UCC (p < 0.0001) Spirometry was performed in 69 and 57%, X-ray in 73 and 58% and asthma challenge test performed in 13 and 5% (UCC and RCC, respectively, p < 0.0001). The frequency of co-morbidities such as heart failure, rheumatologic disease, pulmonary embolism, and diabetes was < 10%.

Conclusion

Many patients suffer from chronic cough or cough requiring medications, with or without co-morbidity; frequently found among menopausal women. Most patients had a substantial work-up performed. The high frequency and the resources consuming work-up program call for systematic coding of disease, systematic patient evaluation and more specific treatment options. The study was approved (ID: no. P-2019-191).

Drivers of respiratory health care demand in Acre state, Brazilian Amazon: a cross-sectional study

Background

The scarce knowledge about the drivers of demand for respiratory health care in the Brazilian Amazon, where the gap of human and physical health care resources is wide, is expanded with two surveys conducted in the west of the region, in Acre state. Potential drivers, informed by a review of twelve recent papers, were classified into seven categories capturing the individual, household, community and macroeconomic dimensions.

Methods

Quantitative field surveys were conducted in 2017 and 2019 based on coupled conglomerate-quota randomization sampling. Adults responded about their own health or their children’s health. The probability of seeking physician care for the latest episode of respiratory illness or dry cough was analysed with multiple nonlinear regressions, having as covariates the potential predictors informed by the literature.

Results

The propensity to seek health care and to purchase medication was larger for children. Influenza-like illness (Despite the exact diagnostic stated by respondents being “influenza”, a virus detection test (such as the PCR test) is not commonly applied, as informed by the Acre state public health service. In consistency, the term “influenza-like illness” is used.) was the most frequently diagnosed disease, followed by pneumonia, suggesting that a health care-seeking rate below 40% may perpetuate health impairment and local contagion. Illnesses’ severity, including the pain experienced, was the main predictor, revealing that subjective perception was more influential than objective individual and household characteristics.

Conclusions

The results suggest that subjective underestimation of respiratory illnesses’ consequences for oneself and for local society could prevent health care from being sought. This is in line with some previous studies but departs from those emphasizing the role of objective factors. Social consequences, of, for instance, a macroeconomic nature, need to be highlighted based on studies detecting long-run relationships among health care demand, health and economic performance at the national level. Depending on the intensity of the trade-off between the costs imposed on the health system by increased demand and on the economy by the reduced productivity of the ill, policy could be adopted to change subjective perceptions of illnesses with nudges and educational and informational interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14171-z.

Incidence and Prevalence of Cough in a Rural Health System: A 20‐Year Study

OBJECTIVE

Understanding the cough population is critical to addressing clinical needs and gaps in best practice. We sought to characterize and stratify cough patients with the hypothesis that there are opportunities to improve access to care in our health system and characterize the population.

METHODS

Following institutional review board exempt status, a retrospective electronic record review was performed on all patients coded with ICD-9 786.2 or ICD-10 is R05 from January 1, 2001 through December 31, 2020 at our health system. Inclusion criteria were one or more visits for cough. The subgroup with more than one visit in each of 2 years was classified as multiple encounters. Patients were characterized by sex, age at first cough encounter, number of cough encounters, smoking status, and insurance status. Results were stratified by year, calculating frequencies, and percentages.

RESULTS

There were 302,284 unique patients diagnosed with cough, among 1,764,387 patients seen in our health system, representing an average incidence of 3.0% (2.7%-3.7%) and prevalence of 4.9% (3.1%-5.6%). New single encounter cough patients totaled 179,963, and new multiple encounter cough patients totaled 122,321. Of the 39,828,073 total encounters, there were 469,802 for new or existing cough (1.17%-1.73% annually). The age at initial presentation demonstrated 36.5% seen <10 years old, with an even distribution over the remaining decades of life. The majority were seen for cough once, but 23.8% of group two patients had two or more visits for cough in a year.

CONCLUSION

We demonstrate a lower-than-expected incidence and prevalence of cough in our health population, suggesting challenges with access to care when compared to 10% prevalence and 3% of encounters previously documented in the literature. The study also provides a platform to explore the importance of pediatric cough, as well as population health and the longitudinal journey of cough patients in underserved areas.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:1191-1196, 2023.

Efficacy and Safety of Eucalyptus for Relieving Cough: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objectives: To assess the efficacy and safety of Eucalyptus globulus Labill (Eucalyptus) on cough. Background: Cough is a common symptom of upper respiratory tract infections (URTIs) and bronchitis. Eucalyptus products are frequently used as over-the-counter cough medications but their efficacy and safety are uncertain. Methods: Randomized controlled trials (RCTs) investigating efficacy and safety of Eucalyptus for cough were systematically searched in electronic databases till February 2021. Two reviewers independently performed study selection, data extraction, and quality assessment. Clinical outcomes including improvement or resolution of overall cough symptoms, cough frequency (CF), and adverse events (AEs) of Eucalyptus were evaluated and analyzed using a random-effects model. Heterogeneity was evaluated using I² and chi-squared test. Results: Six RCTs with 1,857 participants with cough were included in this study. Most of the included studies used Eucalyptus in combination formula (four of six studies). Based on Cochrane's risk of bias criteria, three of six studies (50%) were rated low risk of bias, whereas the remaining were judged as high risk of bias. This study found that Eucalyptus products are more effective than placebo in terms of improvement or resolution of overall cough symptoms with relative risk 1.45 (95% confidence interval (95% CI) 1.26-1.67). Whereas all Eucalyptus formulae reduced CF with weighted mean difference 0.44 (95% CI 0.28-0.60), when compared with placebo. There are no serious AEs associated with Eucalyptus during treatment periods. Mild-to-moderate gastrointestinal symptoms were common AEs reported in a comparable study between Eucalyptus and control groups. Conclusion: The findings indicate that Eucalyptus products are safe for use in cough related to respiratory diseases such as URTIs and bronchitis. However, their efficacy is minimal and of uncertain clinical importance. Further high-quality studies are still necessary to confirm this finding.

Prevalence of chronic cough in China: a systematic review and meta-analysis

Background

Individual studies have indicated variable prevalence for chronic cough, but thus far, there has been no systematic report on the prevalence of this condition.

Methods

In this study, we performed a systematic review and meta-analysis by searching databases including PubMed, Cochrane Library, Web of Science, China National Knowledge Infrastructure, Chinese biomedical literature service system, Wanfang Database, and VIP database, for studies on chronic cough in China published before December 28, 2020. A random effects model was used to calculate pooled prevalence estimates with 95% confidence interval [95%CI], weighted by study size.

Results

Fifteen studies with 141,114 community-based adults were included in the study, showing a prevalence of 6.22% (95% CI 5.03–7.41%). And 21 studies with 164,280 community-based children were included, presenting a prevalence of 7.67% (95% CI 6.24–9.11%). In subgroup meta-analyses, the prevalence in adults was 4.38% (95% CI 2.74–6.02%) in southern China and 8.70% (95% CI 6.52–10.88%) in northern China. In the children population, the prevalence in northern China was also higher than in southern China (northern vs. southern: 7.45% with a 95% CI of 5.50–9.41%, vs. 7.86% with a 95% CI of 5.56–10.16%).

Conclusions

Our population-based study provides relatively reliable data on the prevalence of chronic cough in China and may help the development of global strategies for chronic cough management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01847-w.

Process of diagnosis and treatment of chronic cough in children at primary hospitals

OBJECTIVE

This study aimed to establish a process for the diagnosis and treatment of chronic cough in children suitable at primary hospitals and improve the treatment efficacy rate and improve health economic indicators.

METHODS

Children who visited the Department of Pediatrics, Affiliated Zhou Pu Hospital of the Shanghai Health Medical College from January to December 2021 were randomly assigned to the intervention group (n = 206), in which the diagnosis and treatment process proposed here was applied, and a control group (n = 211) that did not follow the intervention pathway and followed a pathway with the doctors usual practice based on his/her previous experience. Patients were followed up and data were collected at weeks 0 (time of enrollment), 2, 4, 8, and 12 to evaluate the efficacy rate and clinical value.

RESULTS

(1) No significant differences were detected between the two groups in baseline characteristics, including gender, age, duration of cough (weeks), history of allergy in children and parents, and smoking of family members living in the same household (p > 0.05); (2) During the follow-up, all cough symptom scores of the intervention group were lower than the control group. Additionally, at week 12, the treatment efficacy rate of the intervention group (91.70%) was significantly higher than the control group (69.20%) (p < 0.05); (3) The quality of life of children in both groups at week 12 was improved compared to the first visit. However, the total score of the intervention group was significantly higher than the control group (p < 0.05); (4) At week 12, the referral rate was significantly lower in the intervention group (11.17%) than in the control group (21.33%); (5) The intervention group was better than the control group for the mean monthly medication costs, number of days on errors in childhood, and number of days mistakenly worked by family members at week 12 (p < 0.05).

CONCLUSION

The current process of diagnosis and treatment of chronic cough in children at primary hospitals can improve the effective diagnosis and treatment rate, the quality of life, and other parameters, with good effectiveness and feasibility.

Chronic cough caused by choledochoduodenal fistula: a case report

Background

Chronic cough is characterized by cough as the only or main symptom, with a duration of more than 8 weeks and no obvious abnormality in chest X-ray examination. Its etiology is complex, including respiratory disease, digestive system disease, circulation system disease, and psychological disease. Although a set of etiological diagnosis procedures for chronic cough have been established, it is still difficult to diagnose chronic cough and there are still some patients with misdiagnosis.

Case presentation

We present a case of a 54-year-old female patient who had chronic cough for 28 years. Physical examination had no positive signs and she denied any illness causing cough like tuberculosis, rhinitis. Recurrent clinic visits and symptomatic treatment didn’t improve the condition. Finally, gastroscopy identified the possible etiology of choledochoduodenal fistula that was proved by surgery. And after surgery, the patient's cough symptoms were significantly improved.

Conclusion

We report a rare case of chronic cough caused by choledochoduodenal fistula which demonstrates our as yet inadequate recognition of the etiology and pathogenesis. Written informed consent was obtained from the patient.

Efficacy of non-sedating H1-receptor antihistamines in adults and adolescents with chronic cough: A systematic review

Background

Nasal symptoms frequently coexist in patients with chronic cough, and non-sedating H1-receptor antihistamines (nsH1RAs) are often prescribed for cough management in several countries. However, recommendations on the use of nsH1RAs vary among chronic cough guidelines. This study aimed to examine the efficacy of nsH1RAs over placebos in adolescents or adults with chronic cough or allergic respiratory conditions that may present as chronic cough.

Methods

Electronic databases were searched for studies published until November 2020. Randomized placebo-controlled trials of nsH1RAs reporting cough endpoints in adolescents or adults with chronic cough or cough-associated allergic respiratory conditions (allergic rhinitis, allergic asthma, or atopic cough) were included.

Results

A total of 10 placebo-controlled trials were identified. Three studies (one study each involving allergic rhinitis, allergic rhinitis with comorbid asthma, and atopic cough) described baseline and post-treatment cough scores, and all reported significant improvements in subjective cough scores; however, the magnitude of improvement was greater in the 2 studies of patients with atopic cough (relative improvement in cough frequency score: −36.6 ± 8.4%) or seasonal allergic rhinitis-associated cough (cough frequency score: −44.0 ± 7.3% and cough intensity score: −65.7 ± 8.3%) than in the 1 study of allergic rhinitis patients with comorbid asthma (−4.0 ± 1.3%). Meanwhile, the other 7 trials found conflicting results but lacked information on the baseline cough score and did not use validated cough measurement tools; thus, their clinical relevance could not be determined.

Conclusion

Despite the widespread use of nsH1RAs in patients with chronic cough, only a few clinical trials examining their benefits on cough outcomes have been conducted. There may be a subgroup of patients, particularly those with seasonal allergic rhinitis-associated cough or atopic cough, whose cough may improve with nsH1RA treatment. However, adequately powered trials with validated cough measurement tools are warranted to confirm the role of nsH1RAs in the management of patients with allergic phenotypes of chronic cough.

Risk and impact of chronic cough in obese individuals from the general population

BACKGROUND

Obese individuals may be at higher risk of chronic cough. We investigated the risk and impact of chronic cough in obese individuals from the general population.

METHODS

We recorded chronic cough, body mass index (BMI) and other related clinical conditions in 44 554 adults from the Copenhagen General Population Study. Individuals with asthma and/or chronic obstructive pulmonary disease were excluded (n=10 977). BMI was divided into: underweight (BMI <18.5 kg/m²), normal weight (18.5-24.9 kg/m²), overweight (25.0-29.9 kg/m²), obese (30.0-34.9 kg/m²) and severely obese (≥35.0 kg/m²).

RESULTS

Among 33 577 adults from the general population, 27 829 (83%) were non-obese and 5748 (17%) were obese. Compared with individuals with normal weight, multivariable adjusted ORs for chronic cough risk were 1.4 (95% CI 1.2 to 1.6) in overweight, 1.9 (95% CI 1.7 to 2.2) in obese and 2.6 (95% CI 2.1 to 3.2) in severely obese individuals. Mediation analyses showed that chronic cough due to obesity was up to 23% mediated by gastro-oesophageal reflux disease (GERD). Other mediators included low vegetable intake with 10% and occupational exposure with 8%. Among obese individuals, those with versus without chronic cough had worse accompanying respiratory symptoms, more often comorbidities including GERD and diabetes, greater healthcare utilisations, lower lung function and higher blood inflammation (all p<0.05).

CONCLUSION

There is dose-response relationship between BMI and chronic cough, and chronic cough risk is twofold to threefold higher in obese individuals from the general population. This increased risk was partly mediated by GERD, low vegetable intake and occupational exposure, supporting that there may be benefit to gain by ameliorating some of these factors in obese individuals with chronic cough.

Approach to patient with cough by American and Chinese respiratory specialist

Cough is a common pediatric condition. Acute cough is often considered to be self-limiting and not requiring clinical management. However, pediatric patients and their parents often seek remedies for an acute cough. Traditional Chinese Medicine (TCM) specialists have been treating pediatric cough for millennia. Here we present a case of pediatric cough and the approaches taken to it by a Western and Chinese respiratory specialist. We conclude that TCM may provide important and useful insights into the treatment of such pediatric respiratory disease.

Effect of San'ao decoction with scorpio and bombyx batryticatus on CVA mice model via airway inflammation and regulation of TRPA1/TRPV1/TRPV5 channels

ETHNOPHARMACOLOGICAL RELEVANCE

Cough variant asthma (CVA) is characterized with its long-lasting cough symptom on clinic. The mechanism of CVA is related to chronic persistent airway inflammation, airway hyperresponsiveness, etc. The traditional Chinese prescription has achieved good curative effect on CVA treatment through reducing cough counts, decreasing airway hyperresponsiveness and alleviating airway inflammation. The mechanism is associated with reducing IL4, IL-13, NGF and CGRP levels, as well as down-regulating TRPA1/TRPV1/TRPV5 channels in both lung and brain tissues.

AIM OF THE STUDY

The Chinese prescription, San'ao decoction with scorpio and bombyx batryticatus (SSB), is well known in treating cough in asthmatic patients. In this study, the anti-tussive and anti-asthmatic role of SSB, as well as its mechanism on CVA mice model were explored and evaluated via alleviating airway inflammation and regulation of TRP channels.

MATERIALS AND METHODS

The major chemical components in SSB were detected and analyzed by UPLC-QTOF-MS under an optimized chromatographic and MS condition. 60 BALB/c mice were randomly divided into six groups: normal group, model group, dexamethasone group (0.1178 mg/kg/d), SSB high dose group (9.74 g/kg/d), SSB middle dose group (4.87 g/kg/d) and SSB low dose group (2.435 g/kg/d). The cough variant asthma mice model was established by ovalbumin sensitization and challenge. The protective role of SSB on CVA mice model was studied through inducing cough counts by capsaicin, assessing inflammatory cells in peripheral blood and bronchoalveolar lavage fluid (BALF), measuring airway responsiveness, detecting histopathological changes in lung tissues, analyzing cytokines and neuropeptides levels in BALF, as well as examining the mRNA and protein expressions of TRPA1, TRPV1 and TRPV5 in both lung and brain tissues.

RESULTS

17 signal peaks of the chemical components in SSB were identified by using UPLC-QTOF-MS. SSB (especially the high dose and middle dose), showed significantly effects on mice model by reducing mice cough counts (P ＜ 0.01), decreasing eosinophil (EOS) counts in blood (P ＜ 0.01) and inflammatory cell numbers in BALF (P ＜ 0.01), decreasing airway hyperresponsiveness (P ＜ 0.05), reducing the levels of IL-4 (P ＜ 0.05), IL-13 (P ＜ 0.01), NGF (P ＜ 0.01) and CGRP (P ＜ 0.01) in BALF, as well as down regulating the mRNA and protein expressions of TRPA1, TRPV1 and TRPV5 in both lung and brain tissues (P ＜ 0.01).

CONCLUSIONS

SSB showed anti-tussive and anti-asthmatic effects on cough variant asthma mice model by reducing cough counts, improving lung function, alleviating lung injury and airway inflammation. The mechanism of SSB might be associated with the regulation of cytokines and neuropeptides in BALF, as well as the regulation of TRPA1, TRPV1, TRPV5 channels in both lung and brain tissues.

Cough persistence in adults with chronic cough: A 4-year retrospective cohort study

BACKGROUND

There is very limited evidence regarding long-term prognosis of chronic cough. We examined longitudinal outcomes among patients with chronic cough, and explored predictors of cough persistence.

METHODS

A retrospective cohort was constructed of adults who had newly visited a specialist cough clinic in 2012-2013. All had undergone systematic investigation for chronic cough. The Hull Airway Reflux Questionnaire (HARQ) was administered to assess reflux cough symptoms. A follow-up survey was conducted in 2016-2017 to assess cough persistence.

RESULTS

From 418 candidates, 323 participated in the follow-up study; main analyses focused on patients with chronic persistent cough (n = 64; 19.8%) and remitted cough (n = 193; 59.8%). Compared with remitted cough group, chronic persistent cough group had more family history of chronic cough (17.2% vs. 4.7%, p = 0.001) and cold air-sensitive cough (62.5% vs. 44.6%, p = 0.013). The total HARQ score did not differ; however, two items (cough with eating and cough with certain foods) scored significantly higher in chronic persistent cough. In multivariate analyses, a family history of chronic cough (adjusted odds ratio 4.27 [95% confidence interval 1.35-9.89]), cold air-sensitive cough (2.01 [1.09-3.73]), and cough with eating (1.22 [1.02-1.45]) were associated with chronic persistent cough at 4 years.

CONCLUSIONS

Cough persists in about 20% of patients after 4 years following systematic assessment and treatments. Several cough characteristics, such as family history, cold air-sensitivity, or reflux cough, may be associated with cough persistence. Larger cohort studies are warranted to further understand long-term prognosis and confirm predictors of persistence in patients with chronic cough.

Ethnobotanical Survey of Plants Used for Treating Cough Associated with Respiratory Conditions in Ede South Local Government Area of Osun State, Nigeria

In many developing countries, community members depend on their local flora for treating diverse ailments including those affecting the respiratory system. This is often attributed to the high cost and limited access to health care facilities. This present study focused on the documentation of plant species used against cough associated with the respiratory diseases in Ede South Local Government Area of Osun State. The survey was conducted using semi-structured interviews among 100 participants. Information obtained was analyzed using different ethno-botanical indices including relative frequency of citation (RFC) and fidelity level (FL). A total of 87 plant species from 39 families, which was mostly represented by Fabaceae, were reported in the study area. Crinum jagus was the most popular plant used against cough and approximately 32% of the plants have been reported as cough remedies for the first time. However, some of the documented plants have been reported for the treatment of cough and related respiratory diseases in several countries. In terms of the life-form, trees constituted the highest proportion of the medicinal plants (37%), while leaves (36%) were the predominant plant part prescribed for cough. Decoction was the main method of preparing the plants, which were all administered orally. Approximately 63% of the plants were exclusively sourced from the wild. The current study revealed the richness and widespread use of plant species for managing cough associated with respiratory diseases in the study area. The generated inventory contributes to the expanding database of valuable plant resources with medicinal potential in Nigeria and Africa.

The demographic and clinical characteristics of an Italian population of adult outpatients with chronic cough

BACKGROUND

Chronic cough is a major health problem worldwide and patients are best managed in specialised tertiary centres. Little information is available on the characteristics of chronic cough patients in several European countries, including Italy.

AIMS

We report on the demographic, anthropometric and clinical features of a large Italian population of adult chronic cough outpatients (about 1200), who were referred to a specialised clinic in Florence, Italy, from 2008 to 2018.

METHODS

Demographic, environmental, lifestyle and clinical information was collected at enrolment by means of a custom-designed electronic questionnaire that only allowed for uniform responses. A subjective measure of cough-related discomfort (cough score) was also obtained using a modified Borg Scale. A multivariable logistic regression model was defined to identify the patients' characteristics associated with the cough score.

RESULTS

The characteristics of the examined population (n = 1204 outpatients) were strikingly similar to those described elsewhere. Female patients outnumbered the males [n = 847 females, (70.0%)]; both females and males displayed the same average cough score. The median age of outpatients was 61 (quartile 1 = 48; quartile 3 = 70) years; age and cough duration were unrelated to the cough score. Nasal obstruction, coughing during consultation, coughing during meals, throat clearing and the presence of respiratory abnormalities were correlated with the degree of discomfort caused by coughing.

DISCUSSION

The features of chronic cough patients are similar worldwide. The process of cough reflex hypersensitisation may soothe sex-related perceptual differences, leading to similar levels of discomfort.

CONCLUSIONS

There seem to be clinical indicators that help in assessing the level of cough-related discomfort.

ERS guidelines on the diagnosis and treatment of chronic cough in adults and children

These guidelines incorporate the recent advances in chronic cough pathophysiology, diagnosis and treatment. The concept of cough hypersensitivity has allowed an umbrella term that explains the exquisite sensitivity of patients to external stimuli such a cold air, perfumes, smoke and bleach. Thus, adults with chronic cough now have a firm physical explanation for their symptoms based on vagal afferent hypersensitivity. Different treatable traits exist with cough variant asthma (CVA)/eosinophilic bronchitis responding to anti-inflammatory treatment and non-acid reflux being treated with promotility agents rather the anti-acid drugs. An alternative antitussive strategy is to reduce hypersensitivity by neuromodulation. Low-dose morphine is highly effective in a subset of patients with cough resistant to other treatments. Gabapentin and pregabalin are also advocated, but in clinical experience they are limited by adverse events. Perhaps the most promising future developments in pharmacotherapy are drugs which tackle neuronal hypersensitivity by blocking excitability of afferent nerves by inhibiting targets such as the ATP receptor (P2X3). Finally, cough suppression therapy when performed by competent practitioners can be highly effective. Children are not small adults and a pursuit of an underlying cause for cough is advocated. Thus, in toddlers, inhalation of a foreign body is common. Persistent bacterial bronchitis is a common and previously unrecognised cause of wet cough in children. Antibiotics (drug, dose and duration need to be determined) can be curative. A paediatric-specific algorithm should be used.

Impact of Chronic Cough on Health-Related Quality of Life in the Korean Adult General Population: The Korean National Health and Nutrition Examination Survey 2010-2016

Purpose

Chronic cough is a prevalent condition in the community and may pose considerable impairment to quality of life (QoL). However, its disease burden remains largely undefined in the general population. The present study investigated the relationship between chronic cough and health-related QoL in a Korean nationwide population database, with an emphasis on clinical conditions which may confound the impact of cough.

Methods

This study analyzed cross-sectional datasets of adults (aged ≥ 40 years) in the Korean National Health and Nutrition Examination Survey 2010–2016. Health-related QoL was assessed using the 3-level EuroQoL 5-dimension component (EQ-5D-3L) index score. The presence of chronic cough and other conditions were defined using structured questionnaires.

Results

The prevalence of chronic cough was 3.48% ± 0.17% among adults aged ≥ 40 years. The overall EQ-5D-3L index score was significantly lower in subjects with than without chronic cough (0.79 ± 0.01 vs. 0.86 ± 0.00, P < 0.001). In subgroup analyses by age and sex, chronic cough had a notably large impact on QoL in women aged ≥ 65 years (vs. those without chronic cough: 0.55 ± 0.04 vs. 0.70 ± 0.01, P < 0.001), although the mean difference in the scores exceeded the minimally important difference score of 0.05 in all subgroups. In multivariate analyses, chronic cough was significantly associated with QoL, independent of confounders including depression, arthritis, asthma, and chronic obstructive pulmonary disease. In dimension analyses, chronic cough was more associated with anxiety/depression, pain/discomfort, and usual activities than with self-care or mobility in the EQ-5D.

Conclusions

The present study demonstrated significant associations between chronic cough and health-related QoL in a nationwide large general adult population aged ≥ 40 years, which were independent of clinical confounders. The impact of chronic cough was greater in women aged ≥ 65 years. These findings indicate a considerable burden of chronic cough in the general population and warrant further investigations to assess the disease burden of chronic cough in a global scale.

Updates in the field of non-esophageal gastroesophageal reflux disorder

Introduction: Gastroesophageal reflux disease (GERD) is one of the most prevalent conditions in Western Countries, normally presenting with heartburn and regurgitation. Extra-esophageal (EE) GERD manifestations, such as asthma, laryngitis, chronic cough and dental erosion, represent the most challenging aspects from diagnostic and therapeutic points of view because of their multifactorial pathogenesis and low response to proton pump inhibitors (PPIs). In fact, in the case of EE, other causes must by preventively excluded, but instrumental methods, such as upper gastrointestinal endoscopy and laryngoscopy, have low specificity and sensitivity as diagnostic tools. In the absence of alarm signs and symptoms, empirical therapy with a double-dose of PPIs is recommended as a first diagnostic approach. Subsequently, impedance-pH monitoring could help to define whether the symptoms are GERD-related. Areas covered: This article reviews the current literature regarding established and proposed EE-GERD, reporting on all available options for its correct diagnosis and therapeutic management. Expert opinion: MII-pH could help to identify a hidden GERD that causes EE. Unfortunately, standard MII-pH analysis results are often unable to define this association. New parameters such as the mean nocturnal baseline impedance and post-reflux swallow-induced peristaltic wave index may have an improved diagnostic yield, but prospective studies using impedance-pH are needed.

Frequent Sips of the Water for the Management of Gastroesophageal Reflux Induced Refractory Cough: A Case Report and Review of the Literature

BACKGROUND

Chronic cough is often associated with gastroesophageal reflux disease (GERD). The role of gastroenterologist in the management of the chronic cough is to identify and manage GERD. Ineffective esophageal motility is often associated with GERD induced cough. Chronic cough is often refractory to medical and surgical management despite adequate acid control. Unresponsiveness warrants a thorough pulmonary evaluation. The pathophysiology of refractory cough in these patients is poorly understood, and hence management is often challenging.

CASE PRESENTATION

A 75-year-old woman from Ghana was evaluated for GERD associated chronic cough. A 48-hour ambulatory pH study revealed acid exposure of 4.9% and high-resolution manometry showed decreased lower esophageal sphincter pressure, an inadequate response to medical and surgical management of GERD. Postfundoplication ambulatory pH testing demonstrated well-controlled acid reflux but her cough still persisted. Repeat manometry showed an ineffective motility disorder (IEM). Taking frequent sips of water eventually resolved her chronic cough.

CONCLUSION

Frequent sips of water can be used in the management of the gastroesophageal reflux and ineffective motility induced cough. It results in increased esophageal clearance of acid, nonacid reflux, and ingested pharyngeal secretions, thus breaking the cycle of cough generated increased intra-abdominal pressure with reflux and more 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.

Communication of health in experimentally sick men and women: A pilot study

The way people communicate their ill-health and the factors involved in ill-health communication remain poorly known. In the present study, we tested how men and women communicate their sickness and assessed whether sickness-related variables (i.e., body temperature, immune response, subjective sickness symptoms) predicted communicative behaviors. Twenty-two participants were filmed during experimentally induced sickness, triggered by lipopolysaccharide administration (2ng/kg body weight), and after placebo administration, in presence of female care providers. Two trained raters scored participants' communicative behaviors (verbal complaints, moaning and sighs/deep breaths). The physiological and subjective sickness responses were similar in both sexes. Participants were more likely to moan and complain when sick, although the frequency of these behaviors remained low and no clear sex differences was observed. Nevertheless, frequency of sighs/deep breaths was increased amongst sick men but not in women. Sickness-related variables did not predict sigh/deep breath frequency. In this setting, sick men appear to display a lower threshold of expressing their malaise as compared to similarly sick women.

KAAACI Evidence-Based Clinical Practice Guidelines for Chronic Cough in Adults and Children in Korea

Chronic cough is common in the community and causes significant morbidity. Several factors may underlie this problem, but comorbid conditions located at sensory nerve endings that regulate the cough reflex, including rhinitis, rhinosinusitis, asthma, eosinophilic bronchitis, and gastroesophageal reflux disease, are considered important. However, chronic cough is frequently non-specific and accompanied by not easily identifiable causes during the initial evaluation. Therefore, there are unmet needs for developing empirical treatment and practical diagnostic approaches that can be applied in primary clinics. Meanwhile, in referral clinics, a considerable proportion of adult patients with chronic cough are unexplained or refractory to conventional treatment. The present clinical practice guidelines aim to address major clinical questions regarding empirical treatment, practical diagnostic tools for non-specific chronic cough, and available therapeutic options for chronic wet cough in children and unexplained chronic cough in adults in Korea.

The Emerging Role of The Eosinophil and Its Measurement in Chronic Cough

Although the aetiology of chronic cough in guidelines is clearly stated as asthma and related syndromes, gastro-oesophageal reflux disease (GORD), and upper airways disease, the inflammatory mechanisms underlying these conditions differ. Recent studies on asthma have increasingly focused on its molecular phenotypes instead of clinical characteristics. Here, we proposed the hypothesis that divides cough into two groups; the eosinophilic and neutrophilic. This division will enhance our ability to recognise the type of airway inflammation which, as a consequence will lead us to more targeted and personalized treatment approaches.

Measurement of Cough Aerodynamics in Healthy Adults

IMPORTANCE

Cough is a critical human reflex and also among the most frequent symptoms in medicine. Despite the prevalence of disordered cough in laryngeal pathologies, comprehensive and quantitative evaluation of cough in these patients is lacking.

OBJECTIVE

Herein we seek to establish normative values for cough aerodynamics to provide a population standard for reference in future studies.

DESIGN, SETTING, AND PARTICIPANTS

Healthy subjects were recruited from an outpatient clinic to perform voluntary cough. Subjects were instructed on the technique for maximal voluntary cough production with measurements recorded on pneumotachograph. Fifty-two subjects were studied, including 29 women and 23 men with a mean age of 51.6 and 52.3 years, respectively. Main Outcomes and Measures: Cough peak airflow, peak pressure, and expiratory rise time. Results were stratified by age, gender, and height.

RESULTS

Peak airflow demonstrated significant differences across age, gender, and height, with flow increasing according to increasing height. Peak cough pressure also increased with height and was significantly greater in males versus females. Expiratory rise time, the time from glottal opening to peak airflow, did not vary with age or height but was statistically significantly longer in women.

CONCLUSIONS

Cough aerodynamics can be readily measured objectively in the outpatient setting. Expiratory rise time, peak flow, and peak pressure are important aspects of each cough epoch. Normative data provided herein can be used for future studies of patients with laryngotracheal disorders, and these cough parameters may prove to be simple, accessible, and repeatable outcome measures.

Cough in idiopathic pulmonary fibrosis

Many patients with idiopathic pulmonary fibrosis (IPF) complain of chronic refractory cough. Chronic cough is a distressing and disabling symptom with a major impact on quality of life. During recent years, progress has been made in gaining insight into the pathogenesis of cough in IPF, which is most probably "multifactorial" and influenced by mechanical, biochemical and neurosensory changes, with an important role for comorbidities as well. Clinical trials of cough treatment in IPF are emerging, and cough is increasingly included as a secondary end-point in trials assessing new compounds for IPF. It is important that such studies include adequate end-points to assess cough both objectively and subjectively. This article summarises the latest insights into chronic cough in IPF. It describes the different theories regarding the pathophysiology of cough, reviews the different methods to assess cough and deals with recent and future developments in the treatment of cough in IPF.

Survey on attitudes of Italian pediatricians toward cough

CONTEXT

Children's cough is a daily concern for most pediatricians. The management of both acute and chronic cough requires a systematic and comprehensive approach. Despite the approved protocols for management, the pediatric assessment of cough and the corresponding prescribing attitude frequently do not fit these protocols, which can be affected by parental suggestions - sometimes substantially.

OBJECTIVE

The objective of this study was to investigate both the perception and the behavior of a representative sample of Italian pediatricians toward cough in real life.

METHODS

A specific questionnaire consisting of 18 questions was prepared. The questionnaire was completed by 300 pediatricians (all members of PAIDOSS: Italian National Observatory on Health of Childhood and Adolescence) who represented ~300,000 children.

RESULTS

A vast majority of children have cough throughout the year (99.3% of respondents have cough during autumn/winter and 64.7% in spring/summer). Allergic disease is the most frequent suspected cause of chronic cough in children (53%), and this is supported by the high demand for consultations: 73% seek the opinion of allergologists, 62% of otorhinolaryngologists and only 33% of pulmonologists. The majority of pediatricians (92%) reported that they prescribe therapy in acute cough regardless of cough guidelines. Moreover, the survey pointed out the abuse of aerosol therapy (26% in acute cough and 38% in chronic cough) and of antibiotics prescription (22% in acute cough and 42% in chronic cough).

CONCLUSION

Our survey suggests that some Italian pediatricians' therapeutic attitudes should be substantially improved in order to achieve better management of cough in children and to minimize the burden of cough.

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.

Cough Hypersensitivity Syndrome: A Few More Steps Forward

Cough reflex is a vital protective mechanism against aspiration, but when dysregulated, it can become hypersensitive. In fact, chronic cough is a significant medical problem with a high degree of morbidity. Recently, a unifying paradigm of cough hypersensitivity syndrome has been proposed. It represents a clinical entity in which chronic cough is a major presenting problem, regardless of the underlying condition. Although it remains a theoretical construct, emerging evidence suggests that aberrant neurophysiology is the common etiology of this syndrome. Recent success in randomized clinical trials using a P2X3 receptor antagonist is the first major advance in the therapeutics of cough in the past 30 years; it at last provides a strategy for treating intractable cough as well as an invaluable tool for dissecting the mechanism underpinning cough hypersensitivity. Additionally, several cough measurement tools have been validated for use and will help assess the clinical relevance of cough in various underlying conditions. Along with this paradigm shift, our understanding of cough mechanisms has improved during the past decades, allowing us to continue to take more steps forward in the future.

The burden of segregated respiratory diseases in India and the quality of care in these patients: Results from the Asia-Pacific Burden of Respiratory Diseases study

BACKGROUND

Chronic respiratory diseases such as asthma, allergic rhinitis (AR), chronic obstructive pulmonary disease (COPD), and rhinosinusitis are becoming increasingly prevalent in the Asia-Pacific region. The Asia-Pacific Burden of Respiratory Diseases study examined the disease and economic burden of AR, asthma, COPD, and rhinosinusitis across the Asia-Pacific and more specifically India.

OBJECTIVES

To estimate the proportion of adults receiving care for asthma, AR, COPD, and rhinosinusitis and assess the economic burden, both direct and indirect of these chronic respiratory disease.

SUBJECTS AND METHODS

Consecutive participants aged ≥18 years with a primary diagnosis of asthma, AR, COPD, or rhinosinusitis were enrolled. Surveys comprising questions about respiratory disease symptoms, healthcare resource utilization, work productivity, and activity impairment were completed by treating physicians and participants during one study visit. Costs, indirect and direct, that contributed to treatment for each of the four respiratory diseases were calculated.

RESULTS

A total of 1000 patients were enrolled. Asthma was the most frequent primary diagnosis followed by AR, COPD, and rhinosinusitis. A total of 335 (33.5%) patients were diagnosed with combinations of the four respiratory diseases; the most frequently diagnosed combinations were asthma/AR and rhinosinusitis/AR. Cough or coughing up sputum was the primary reason for the current visit by patients diagnosed with asthma and COPD while AR patients reported a watery, runny nose, and sneezing; patients with rhinosinusitis primarily reported a colored nasal discharge. The mean annual cost per patient was US$637 (SD 806). The most significant driver of direct costs was medications. The biggest cost component was productivity loss.

CONCLUSIONS

Given the ongoing rapid urbanization of India, the frequency of respiratory diseases and their economic burden will continue to rise. Efforts are required to better understand the impact and devise strategies to appropriately allocate resources.

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.

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.

Herbal Medicine for Cough: a Systematic Review and Meta-Analysis

BACKGROUND

The aim of this review was to systematically assess the literature on herbal medicine for cough as a symptom of upper respiratory tract infections and common cold.

METHODS

The Cochrane Library, Scopus, MEDLINE/PubMed, and Embase were searched through March 2012 for RCTs testing the effects of herbal medicine for cough. Risk of bias was assessed using the Cochrane tool.

RESULTS

34 RCTs (N = 7,083) on Pelargonium sidoides (11 RCTs), Echinacea (8 RCTs), Andrographis paniculata (6 RCTs), ivy/primrose/thyme (4 RCTs), essential oils (4 RCTs) and bakumondoto (1 RCT) were included. Controls were mainly placebo. Most studies had a low risk of bias. The meta-analysis revealed strong evidence for A. paniculata (SMD = -1.00, 95% CI = -1.85, -0.15; P<0.001) and ivy/primrose/thyme (RR = 1.40, 95% CI = 1.23, 1.60; P<0.001) in treating cough; moderate evidence for P. sidiodes (RR = 4.60; 95% CI = 2.89,7.31; P<0.001), and limited evidence for Echinacea (SMD = -0.68; 95% CI = -1.32, -0.04; P = 0.04).

CONCLUSION

This review found strong evidence for A. paniculata and ivy/primrose/thyme-based preparations and moderate evidence for P. sidoides being significantly superior to placebo in alleviating the frequency and severity of patients' cough symptoms. Additional research, including other herbal treatments, is needed in this area.

Defining Chronic Cough: A Systematic Review of the Epidemiological Literature

Purpose

Recent evidence suggests a global burden of chronic cough in general populations. However, the definitions vary greatly among epidemiological studies, and none have been validated for clinical relevance. We aimed to examine previous epidemiological definitions in detail and explore the operational characteristics.

Methods

A systematic review was conducted for epidemiological surveys that reported the prevalence of chronic cough in general adult populations during the years 1980 to 2013. A literature search was performed on Pubmed and Embase without language restriction. Epidemiological definitions for chronic cough were classified according to their components, such as cutoff duration. Meta-analyses were performed for the male-to-female ratio of chronic cough prevalence to explore operational characteristics of epidemiological definitions.

Results

A total of 70 studies were included in the systematic review. The most common epidemiological definition was identified as 'cough ≥3 months' duration without specification of phlegm (n=50); however, it conflicted with the cutoff duration in current clinical guidelines (cough ≥8 weeks). Meta-analyses were performed for the male-to-female ratio of chronic cough among 28 studies that reported sex-specific prevalence using the most common definition. The pooled male-to-female odds ratio was 1.26 (95% confidence interval 0.92-1.73) with significant heterogeneity (I²=96%, P<0.001), which was in contrast to clinical observations of female predominance from specialist clinics. Subgroup analyses did not reverse the ratio or reduce the heterogeneity.

Conclusions

This study identified major issues in defining chronic cough in future epidemiological studies. The conflict between epidemiological and clinical diagnostic criteria needs to be resolved. The unexpected difference in the gender predominance between the community and clinics warrants further studies. Clinical validation of the existing definition is required.

Cough hypersensitivity as a neuro-immune interaction

Cough is an intrinsic protective reflex. However, chronic cough affects a considerable proportion of general population and has a major impact on quality of life. A recent paradigm shift to ‘cough hypersensitivity syndrome’ suggests that chronic cough arises from hypersensitivity of the airway sensory nerves. As cough reflex is determined by interaction of the nervous system with immune system, persistent dysregulation of one or both of these systems may lead to chronic cough hypersensitivity. Here we review the current evidence for the neuro-immune interactions that underlie cough hypersensitivity and discuss future therapeutic strategies.

The impact of chronic cough: a cross-sectional European survey

PURPOSE

Studies that investigate the impact of chronic cough have largely focused on patients attending secondary care. Our aim was to investigate the opinions of the wider general population across Europe.

METHODS

An internet survey was made available in 12 languages on the European Lung Foundation website, between January 2012 and April 2013.

RESULTS

Of 1120 respondents from 29 different European countries, 67 % were female, mean age 51 years (SD 15), median cough duration 2-5 years. The majority of respondents reported cough impacted their quality of life, mood and ability to undertake activities. Despite 72 % of respondents having visited their doctor ≥3 times, only 53 % had received a diagnosis. Asthma was the most common diagnosis (23 %). Most respondents reported limited or no effectiveness of medications. 88 % of respondents reported that they would like more information to be available on chronic cough.

CONCLUSIONS

Chronic cough has a negative impact on quality of life. Further work is needed to raise awareness, promote management strategies, develop effective treatments and consider the educational and support needs of patients with chronic cough.

Pathophysiology of Clinical Symptoms in Acute Viral Respiratory Tract Infections

In this article we discuss the pathophysiology of common symptoms of acute viral respiratory infections (e.g., sneezing, nasal discharge, sore throat, cough, muscle pains, malaise, and mood changes). Since clinical symptoms are not sufficient to determine the etiology of viral respiratory tract infections, we believe that the host defense mechanisms are critical for the symptomatology. Consequently, this review of literature is focused on the pathophysiology of respiratory symptoms regardless of their etiology. We assume that despite a high prevalence of symptoms of respiratory infection, their pathogenesis is not widely known. A better understanding of the symptoms' pathogenesis could improve the quality of care for patients with respiratory tract infections.

Reliability and validity of a korean version of the leicester cough questionnaire

PURPOSE

There are no specific tools for measurement of the severity of chronic cough in Korea. We developed a Korean version of the Leicester Cough Questionnaire (LCQ) and tested its scaling and clinical properties.

METHODS

The LCQ was adapted for Korean conditions following a forward-backward translation procedure. All patients referred to chronic cough clinics at 5 university hospitals between May 2011 and October 2013 completed 2 questionnaires, the LCQ and the Short-Form 36 (SF-36), upon presentation and completed the LCQ and the Global Rating of Change (GRC) upon follow-up visits after 2 or 4 weeks. Concurrent validation, internal consistency, repeatability, and responsiveness were determined.

RESULTS

For the concurrent validation, the correlation coefficients (n=202 patients) between the LCQ and SF-36 varied between 0.42 and 0.58. The internal consistency of the LCQ (n=207) was high for each of the domains with a Cronbach's alpha coefficient of 0.82-0.94. The repeatability of the LCQ in patients with no change in cough (n=23) was high, with intra-class correlation coefficients of 0.66-0.81. Patients who reported an improvement in cough (n=30) on follow-up visits demonstrated significant improvement in each of the domains of the LCQ.

CONCLUSIONS

The Korean version of the LCQ is a valid and reliable questionnaire for measurement of the severity of cough in patients with chronic cough.

Nonpharmacological interventions for refractory chronic cough patients: systematic review

BACKGROUND

For people with refractory chronic cough, nonpharmacological interventions are emerging as alternatives to antitussive medications. These treatments generally are delivered by physiotherapists and speech and language therapists and consist of education, breathing exercises, cough suppression techniques, and counselling. Although the number of studies investigating these treatment options has increased in recent years there has not been a systematic review of the efficacy of these treatment options.

METHODS

Studies were searched for in EMBASE, AMED, Medline, CINAHL, and PsycINFO databases. Bibliographies of studies and reviews were searched by hand. Critical appraisal was carried out by one reviewer using the SIGN appraisal tools and Cochrane handbook for systematic reviews.

RESULTS

From a total of 184 studies, 5 full-text English language articles were included in the review. Nonpharmacological interventions were found to significantly reduce cough reflex sensitivity, improve quality of life, and lead to reductions in cough severity and frequency. However, few studies used validated and reliable tools to measure cough severity and frequency thereby limiting the robustness of these findings.

CONCLUSION

Present data support the use of two to four sessions of education, cough suppression techniques, breathing exercises, and counselling in order to achieve improvements in cough sensitivity and cough-related quality of life for people with chronic refractory cough. Due to the lack of validated outcome measures, results for other aspects of cough should be interpreted with caution. There is a need for additional larger-powered comparative studies investigating nonpharmacological interventions for refractory chronic cough.

A worldwide survey of chronic cough: a manifestation of enhanced somatosensory response

Reports from individual centres suggest a preponderance of females with chronic cough. Females also have heightened cough reflex sensitivity. Here we have reviewed the age and sex of unselected referrals to 11 cough clinics. To investigate the cause of any observed sex dimorphism, functional magnetic resonance imaging of putative cough centres was analysed in normal volunteers. The demographic profile of consecutive patients presenting with chronic cough was evaluated. Cough challenge with capsaicin was undertaken in normal volunteers to construct a concentration-response curve. Subsequent functional magnetic resonance imaging during repeated inhalation of sub-tussive concentrations of capsaicin observed areas of activation within the brain and differences in the sexes identified. Of the 10,032 patients presenting with chronic cough, two-thirds (6591) were female (mean age 55 years). The patient profile was largely uniform across centres. The most common age for presentation was 60-69 years. The maximum tolerable dose of inhaled capsaicin was lower in females; however, a significantly greater activation of the somatosensory cortex was observed. Patients presenting with chronic cough from diverse racial and geographic backgrounds have a strikingly homogeneous demographic profile, suggesting a distinct clinical entity. The preponderance of females may be explained by sex-related differences in the central processing of cough sensation.

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.

Cough in the elderly population: relationships with multiple comorbidity

BACKGROUND

The epidemiology of cough in the elderly population has not been studied comprehensively. The present study aimed to investigate the epidemiology of cough in a community elderly population, particularly in relation with their comorbidity.

METHODS

A cross-sectional analysis was performed using a baseline dataset from the Korean Longitudinal Study on Health and Aging, a community-based elderly population cohort study. Three types of cough (frequent cough, chronic persistent cough, and nocturnal cough) were defined using questionnaires. Comorbidity was examined using a structured questionnaire. Health-related quality of life was assessed using the Short Form 36 questionnaire.

RESULTS

The prevalence was 9.3% for frequent cough, 4.6% for chronic persistent cough, and 7.3% for nocturnal cough. In multivariate logistic regression analyses, smoking, asthma and allergic rhinitis were found to be risk factors for cough in the elderly. Interestingly, among comorbidities, constipation and uncontrolled diabetes mellitus (HbA1c ≥ 8%) were also found to have positive associations with elderly cough. In the Short Form 36 scores, chronic persistent cough was independently related to impairment of quality of life, predominantly in the mental component.

CONCLUSIONS

Cough has a high prevalence and is detrimental to quality of life in the elderly. Associations with smoking, asthma and rhinitis confirmed previous findings in younger populations. Previously unrecognised relationships with constipation and uncontrolled diabetes mellitus suggested the multi-faceted nature of cough in the elderly.