Future Directions in the Clinical Management of Cough

Gastroesophageal reflux disease and the risk of respiratory diseases: a Mendelian randomization study

BACKGROUND

Observational studies have suggested a suspected association between gastroesophageal reflux disease (GERD) and respiratory diseases, but the causality remains equivocal. The goal of this study was to evaluate the causal role of GERD in respiratory diseases by employing Mendelian randomization (MR) studies.

METHODS

We conducted Mendelian randomization analysis based on summary data of genome-wide association studies (GWASs) and three MR statistical techniques (inverse variance weighted, weighted median and MR-Egger) were employed to assess the probable causal relationship between GERD and the risk of respiratory diseases. Sensitivity analysis was also carried out to ensure more trustworthy results, which involves examining the heterogeneity, pleiotropy and leave-one-SNP-out method. We also identified 33 relevant genes and explored their distribution in 26 normal tissues.

RESULTS

In the analysis, for every unit increase in developing GERD, the odds ratio for developing COPD, bronchitis, pneumonia, lung cancer and pulmonary embolism rose by 72% (ORIVW = 1.72, 95% CI 1.50; 1.99), 19% (ORIVW = 1.19, 95% CI 1.11; 1.28), 16% (ORIVW = 1.16, 95% CI 1.07; 1.26), 0. 3% (ORIVW = 1.003, 95% CI 1.0012; 1.0043) and 33% (ORIVW = 1.33, 95% CI 1.12; 1.58), respectively, in comparison with non-GERD cases. In addition, neither heterogeneity nor pleiotropy was found in the study. This study also found that gene expression was higher in the central nervous system and brain tissue than in other normal tissues.

CONCLUSIONS

This study provided evidence that people who developed GERD had a higher risk of developing COPD, bronchitis, pneumonia, lung cancer and pulmonary embolism. Our research suggests physicians to give effective treatments for GERD on respiratory diseases. By exploring the gene expression, our study may also help to reveal the role played by the central nervous system and brain tissue in developing respiratory diseases caused by GERD.

Irritant-Induced Chronic Cough Triggers: A Scoping Review and Clinical Checklist

Purpose The primary aim of this review was to identify environmental irritants known to trigger chronic cough through the life span and develop a comprehensive clinically useful irritant checklist. Method A scoping review was conducted using the Preferred Reporting Items for Systematic Review and Meta-Analysis Extension for Scoping Reviews, checklist, and explanation. English-language, full-text resources were identified through Medline, PsycINFO, SPORTDiscus, Web of Science, and ProQuest Dissertations and Theses Global. Results A total of 1,072 sources were retrieved; of these, 109 were duplicates. Titles of abstracts of 963 articles were screened, with 295 selected for full-text review. Using the exclusion and inclusion criteria listed, 236 articles were considered eligible and 214 different triggers were identified. Triggers were identified from North America, Europe, Africa, Asia, and Australia. Occupational exposures were also delineated. Conclusions A clinically useful checklist of both frequently encountered triggers and idiosyncratic or rare triggers was developed. The clinical checklist provides a unique contribution to streamline and standardize clinical assessment of irritant-induced chronic cough. The international scope of this review extends the usefulness of the clinical checklist to clinicians on most continents.

The Multidimensional Cough Index: A Practical Scale to Measure Cough and Sputum

BACKGROUND

There currently is a lack of easy-to-use instruments with which to assess cough. The aim of the present study was to develop a scale for measuring the characteristics of cough and sputum.

METHODS

The authors developed a scale for assessing cough, including aspects such as intensity, frequency, physical impact, psychosocial impacts and sputum characteristics. The first four components were scored using a Cough Index, with a range of 0 to 20. Sputum information included volume, appearance, and hemoptysis. The scale was administered to 105 patients and re-administered to 51 about two weeks later. The patients also reported cough frequency and intensity using a 100-mm visual analogue scale (VAS) and answered the Leicester Cough Questionnaire (LCQ). Additionally, 12 patients with acute exacerbation (AE) of chronic airways disease were interviewed upon admission to and discharge from the hospital.

RESULTS

Analysis identified only one factor for the Cough Index, and Cronbach's alpha value was 0.819. Cough Index was significantly correlated with VAS_frequency (r = 0.651, p < 0.0001), VAS_intensity (r = 0.543, p<0.0001), and LCQ (r = -0.824, p < 0.0001). The intraclass correlation coefficient of test-retest scores was 0.779. The median Cough Index significantly decreased after AE treatment, as did the number of patients reporting increased sputum production and greenish and dark sputum. A Cough Index ≥ 4 distinguished respiratory patients from healthy subjects, with a sensitivity of 80% and a specificity of 85%.

CONCLUSION

The Multidimensional Cough Index condenses complex aspects related to cough and sputum production into a single instrument, with satisfactory validation.

The impact of chronic non-specific cough on children and their families: A narrative literature review

The aim of this article is to critically appraise and synthesize research that examines the impact chronic non-specific cough has on children and their families and to highlight gaps within the research. Chronic non-specific cough refers to a persistent cough without a specific diagnosis. While studies have begun to examine the impact on children and their families, this research has not been synthesized and appraised. A narrative literature review was undertaken. A comprehensive and systematic search was undertaken, using CINAHL, MEDLINE, British Nursing Index, PsycINFO, Cochrane Wiley Library and ASSIA databases. Studies were critically appraised for quality using the Hawker et al.'s appraisal tool. A narrative review of the findings was undertaken. Nine quantitative studies were included in the review. The article suggests that chronic non-specific cough affects the quality of life of both families and children, affecting quality of sleep, impacting upon participation in activities, causing emotional distress and creating substantial demand on the health service. Furthermore, the research highlighted the worries experienced by parents in relation to the cause of their child's cough. The review did not identify any qualitative research in this area and only one study collected data directly from children.

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.

Characteristics of Chinese patients with cough in primary care centre

Background

Cough is one of the most common respiratory symptoms and is well characterized in specialized cough clinics with high success rates of diagnosis and treatment. However, there is a paucity of data regarding cough in primary care settings. The present study aimed at investigating clinical epidemiology of cough through a national study of two questionnaire surveys sent to primary care physicians in China.

Methods

Approximately 18,000 subjects recruited were having daytime or night symptoms of cough and diagnoses of respiratory disease from February 2005 to April 2006 as Survey 1 and from June 2007 to December 2007 as Survey 2. Patients suffering from respiratory malignancy, hyperthyroidism, hypertension, heart disease, diabetes, severe hypohepatia or renal dysfunction, pregnancy, possible pregnancy or lactation, neutropenia were not eligible. Information regarding demography, history of allergies, symptomatic profile, treatment and curative effects for cough was elicited.

Results

8216 questionnaires were collected in Survey 1 and 9711 in Survey 2. The mean values of ages were 25.7 and 22.3 years old, respectively. Symptoms included expectoration (74% and 76%), wheeze (59% and 74%), breathlessness (22% and 26%), chest pain (9% and 13%) and fever (15% and 18%). About 15% and 23% patients had hypersusceptibility, of whom 6% to 17% had a family history. More than 50% of the cases had histories of allergic rhinitis, asthma, conjunctivitis or atopic dermatitis. Asthma, COPD, and bronchitis were dominant etiologies of cough. Procaterol or the combination of antibiotics and steroids were used as the treatment.

Conclusion

Causes and outcomes of cough differed with ages and time in this particular national study, while successful and precise diagnosis and management of cough in primary care settings need to be further improved in China.

The Current State of Cough Research: The Clinician’s Perspective

Cough is one of the most common reasons for medical consultation and it is responsible for a large human and socioeconomic burden. Current guidelines provide a useful framework for cough management and summarize current knowledge of causes and optimal testing sequences and treatments of cough. However, research is needed on the role of noninvasive airway inflammation measurement in assessing etiology; optimal treatment of postinfectious cough or cough due to gastroesophageal reflux disease; protussive treatment; causes of chronic cough in immunocompromised hosts; and characteristics and management of psychogenic cough. The effects of the use or nonuse of evidence-based guidelines should be documented. An empiric, integrative approach to management of chronic cough also needs further validation.