Prevalence, pathogenesis, and causes of chronic cough

Cough and cough hypersensitivity as treatable traits of asthma

Cough is a common and troublesome symptom in people with asthma and is often associated with poorer asthma control and exacerbations. Apart from asthma, other causes or comorbidities might underlie cough in asthma, such as rhinosinusitis and bronchiectasis. Eosinophilic inflammation and bronchoconstriction can lead to an acute episode of cough or worsen chronic cough. Cough hypersensitivity with laryngeal paraesthesia, allotussia, and hypertussia might underlie the cough of asthma through augmented sensory nerve excitability of upper-airway vagal sensory nerves. Cough associated with bronchoconstriction and type 2 inflammation should respond to inhaled corticosteroids and long-acting β-adrenoceptor agonist therapy. For cough hypersensitivity in adults, speech and language therapy and neuromodulators (eg, gabapentin) could be considered. In children, there is no consistent association of asthma with cough sensitivity or between cough and asthma severity. Further research is needed to realise the potential of cough as a measure of asthma control, to understand the mechanisms of cough in asthma, and to develop safe, effective treatments and a precision-medicine approach to the management of cough in asthma in children and adults.

Zi-Su-Zi decoction improves airway hyperresponsiveness in cough-variant asthma rat model through PI3K/AKT1/mTOR, JAK2/STAT3 and HIF-1α/NF-κB signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Cough-variant asthma (CVA) is one of the most common causes of chronic cough. Its pathogenesis is closely related to chronic airway inflammation and airway hyperresponsiveness. CVA belongs to the category of "wind cough" in Traditional Chinese medicine (TCM). Zi-Su-Zi decoction (ZSD) is a Chinese herbal formula that is clinically used for the treatment of cough and asthma, especially CVA. However, the mechanism of action remains unclear.

AIM OF THE STUDY

In this study, we aimed to explore the potential mechanism by which ZSD improves CVA airway hyperresponsiveness.

MATERIALS AND METHODS

The targets of ZSD in CVA were studied using a Network pharmacology. The main chemical components of ZSD were detected and analyzed using ultra-high-pressure liquid chromatography (UHPLC-MS/MS). In animal experiments, the rat model of CVA was established using Ovalbumin (OVA)/Aluminum hydroxide (AL(OH)3) sensitization. Moreover, the experiment also evaluated cough symptoms, percentage of eosinophils (EOS%), pulmonary function tests, histopathological sections, blood cytokine levels, mRNA and protein levels.

RESULTS

The results showed that Network pharmacology suggested 276 targets of ZSD and CVA and found that ZSD treatment with CVA was closely related to the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway. UHPLC-MS/MS revealed that ZSD contained 52 main chemical components. Compared with the model group, the cough symptoms of the rats in the different ZSD concentration groups were relieved, the EOS% index was lowered, and body weight was increased. HE staining showed that ZSD reduced airway inflammation, edema and hyperplasia, thereby improving the pathological structure of lung tissue, and the effect of high-dose ZSD was especially significant. Our most important finding was that ZSD blocked the entry of hypoxia-inducible factor-1α (HIF-1α), signal transducer and activator of transcription-3 (STAT3) and nuclear factor kappa-B (NF-κB) into the nucleus by interfering with PI3K/AKT1/mechanistic target of rapamycin (mTOR), and janus kinase 2 (JAK2) signaling factors. Consequently, inhibiting the release of cytokines and immunoglobulin-E, thereby reducing airway hyperresponsiveness (AHR) and partially reverses airway remodeling.

CONCLUSIONS

This study showed that ZSD can improve airway hyperresponsiveness and partially reverse airway remodeling by inhibiting the PI3K/AKT1/mTOR, JAK2/STAT3 and HIF-1α/NF-κB signaling pathways. Therefore, ZSD is an effective prescription for the treatment of CVA.

Characteristics and Management of Patients with Refractory or Unexplained Chronic Cough in Outpatient Hospital Clinics in Spain: A Retrospective Multicenter Study

PURPOSE

Chronic cough (cough that persists for ≥ 8 weeks) can cause a range of physical symptoms and psychosocial effects that significantly impair patients' quality of life. Refractory chronic cough (RCC) and unexplained chronic cough (UCC) are challenging to diagnose and manage, with substantial economic implications for healthcare systems.

METHODS

This retrospective multicenter non-interventional study aimed to characterize the profile and health resource consumption of patients with RCC or UCC who attended outpatient clinics at Spanish hospitals. Data were collected from medical records of patients with RCC or UCC for up to 3 years before study inclusion.

RESULTS

The patient cohort (n = 196) was representative of the chronic cough population (77.6% female, mean age 58.5 years). Two-thirds of patients (n = 126) had RCC. The most frequently visited doctors were pulmonologists (93.4% of patients) and primary care physicians (78.6%), with a mean of 5 visits per patient over three years' observation. The most common diagnostic tests were chest x-ray (83.7%) and spirometry with bronchodilation (77.0%). The most commonly prescribed treatments were proton pump inhibitors (79.6%) and respiratory medications (87.8%). Antibiotics were prescribed empirically to 56 (28.6%) patients. Differences between RCC or UCC groups related mainly to approaches used to manage cough-associated conditions (gastroesophageal reflux disease, asthma) in patients with RCC.

CONCLUSION

RCC and UCC are responsible for high health resource utilization in Spanish hospitals. Specific treatments targeting the pathological processes driving chronic cough may provide opportunities to reduce the associated burden for patients and healthcare systems.

Cough desensitization treatment for patients with refractory chronic cough: results of a second pilot randomized control trial

OBJECTIVE

The purpose of this study was to collect pilot efficacy data on a novel treatment for refractory chronic cough (RCC), which we call cough desensitization treatment (CDT).

DESIGN AND METHODS

In this parallel cohort, sham-controlled, randomized controlled trial, 21 adults with RCC were randomly assigned to 12 sessions of either CDT (progressive doses of aerosolized capsaicin while behaviorally suppressing cough; n = 11) or a sham treatment (repeated exposure to aerosolized saline; n = 9). The Leicester Cough Questionnaire (LCQ) was the primary outcome measure. Perceived cough severity with a visual analogue scale and cough challenge testing (for measuring cough-reflex sensitivity) were secondary outcome measures. Data were analyzed with mixed effects linear regression and follow-up contrasts.

RESULTS

Results on all measures favored CDT. Excluding one sham participant, whose baseline LCQ scores were deemed unreliable, mean change in LCQ at 3-weeks post treatment was 6.35 and 2.17 in the CDT and sham groups, respectively. There was moderate to strong evidence of a greater improvement in the CDT group in total LCQ score (p = .058) and LCQ Psychological domain (p = .026) and Physical domain (p = .045) scores. Strong evidence was found for a greater reduction in urge-to-cough during CCT in the CDT group (p = .037) and marginal for a reduction in the capsaicin cough-reflex sensitivity (p = .094). There was weak evidence of a greater reduction in cough severity in the CDT group (p = .103).

DISCUSSION

Although the study is limited due to the small sample size, the data provide additional evidence supporting further research on CDT. CDT resulted in a greater change in the primary efficacy measure (LCQ) than both pharmaceutical and behavioral treatments currently found in the literature.

TRIAL REGISTRATION

This trial (NCT05226299) was registered on Clinicaltrials.gov on 07/02/2022.

A Chronic Cough and Something More: An Unusual Presentation of Hepatocellular Carcinoma

Liver cancer is one of the main contributors to cancer-related death and is the fifth most frequent cancer worldwide. Hepatocellular carcinoma (HCC), the most common of liver cancers, is most frequently diagnosed incidentally during routine imaging in high-risk patients with cirrhosis. However, patients with advanced disease may present with upper abdominal pain, early satiety, weight loss, and a palpable upper abdominal mass. We describe a case of HCC in a 69-year-old male presenting exclusively with an intractable cough, which improved after transarterial chemoembolization-raising awareness of the importance of having a systematic and physiopathology-based approach to chronic cough to have an adequate diagnosis and treatment.

Development and clinical validation of Swaasa AI platform for screening and prioritization of pulmonary TB

Acoustic signal analysis has been employed in various medical devices. However, studies involving cough sound analysis to screen the potential pulmonary tuberculosis (PTB) suspects are very few. The main objective of this cross-sectional validation study was to develop and validate the Swaasa AI platform to screen and prioritize at risk patients for PTB based on the signature cough sound as well as symptomatic information provided by the subjects. The voluntary cough sound data was collected at Andhra Medical College-India. An Algorithm based on multimodal convolutional neural network architecture and feedforward artificial neural network (tabular features) was built and validated on a total of 567 subjects, comprising 278 positive and 289 negative PTB cases. The output from these two models was combined to detect the likely presence (positive cases) of PTB. In the clinical validation phase, the AI-model was found to be 86.82% accurate in detecting the likely presence of PTB with 90.36% sensitivity and 84.67% specificity. The pilot testing of model was conducted at a peripheral health care centre, RHC Simhachalam-India on 65 presumptive PTB cases. Out of which, 15 subjects truly turned out to be PTB positive with a positive predictive value of 75%. The validation results obtained from the model are quite encouraging. This platform has the potential to fulfil the unmet need of a cost-effective PTB screening method. It works remotely, presents instantaneous results, and does not require a highly trained operator. Therefore, it could be implemented in various inaccessible, resource-poor parts of the world.

Membranous Vocal Fold Lesions in Patients With Chronic Cough: A Case Series

OBJECTIVES

Trauma related to chronic cough and forceful glottal closure has been associated with lesions of the vocal process; however, there is limited description of cough leading to membranous vocal fold lesions. We present a series of mid-membranous vocal fold lesions in a cohort of patients with chronic cough, with a proposed mechanism of lesion formation.

METHODS

Patients treated for chronic cough with membranous vocal fold lesions affecting phonation were identified. Presentation, diagnosis, treatment strategies (behavioral, medical, and surgical), patient-reported outcome measures (PROMs), and videostroboscopy were reviewed.

RESULTS

Five patients are included (four females, one male, aged 56±16 years). Mean cough duration was 2.6±3.5 years. All patients were on acid suppressive medications for existing gastroesophageal reflux disease (GERD) prior to referral. All lesions were identified at the mid-membranous vocal folds and morphologically encompassed a wound healing spectrum between ulceration and/or granulation tissue (granuloma) formation. Patients were treated in an interdisciplinary fashion with behavioral cough suppression therapy, superior laryngeal nerve block, and neuromodulators. Three had persistent lesions requiring procedural intervention (one office-based steroid injection and two surgical excisions). At the completion of treatment, all five patients had improvement in Cough Severity Index with an average decrease of 15.2±4.8. All but one patient had improvement in their Voice Handicap Index-10 with an average decrease of 13.2±11.1. One patient undergoing surgical intervention was noted to have a persistent lesion on follow-up.

CONCLUSION

Mid-membranous vocal fold lesions in patients with chronic cough are uncommon. When they do occur, they represent epithelial change arising in context of shear injury and are distinct from phonotraumatic lesions in the lamina propria. An interdisciplinary approach including behavioral cough suppression therapy, neuromodulators, superior laryngeal nerve block, and acid suppression are reasonable for initial management, reserving surgical intervention for refractory lesions once the inciting source of injury has been controlled.

[Chronic cough]

Coughing is an important protective reflex of the respiratory tract and primarily serves clearance of the bronchial system. It is also an exceptionally common symptom in outpatient care that can be an expression of a variety of diseases. Coughing duration of longer than 8 weeks is referred to as chronic cough. A structured, often interdisciplinary diagnostic process is essential. The aim here is to identify causal treatment options, avoiding overdiagnosis and simultaneously not overlooking severe illness. This article discusses current diagnostic procedures, important differential diagnoses and possible treatment options.

Can clinical characteristics differentiate patients with unexplained chronic cough from patients with asthma and COPD?

Background: Chronic cough is reported in up to 20% of the adult population and often persists despite medical treatment with currently available therapies. Many clinical conditions, including asthma and chronic obstructive pulmonary disease (COPD), must be excluded before making a Unexplained chronic cough diagnosis. Methods: The primary objective was to use a large hospital dataset to compare clinical features of patients with a primary diagnosis of UCC with those with asthma or COPD without a primary diagnosis of UCC to help clinicians differentiate between these conditions more readily. Data were collected for all hospitalization and outpatient medical encounters for each patient between November 2013 and December 2018. Information included demographics, encounter dates, medications prescribed at every encounter for chronic cough, lung function testing, and hematologic parameters. Asthma and COPD were combined into one group to ensure there was no overlap with UCC and due to limitations of International Classification of Diseases coding to confirm an asthma(A)/COPD diagnosis. Results: Female gender represented 70% of encounters for UCC versus 61.8% for asthma/COPD (p < 0.0001); the mean age was 56.9 years for UCC versus 50.1 years for A/COPD (p < 0.0001). The number of patients on cough medications and the cough medication frequency were significantly higher in the UCC versus A/COPD group (p < 0.0001). UCC versus A/COPD patients had a total of eight versus three cough-related encounters over the study duration (i.e., 5 years) (<0.0001). The average interval between successive encounters was less for UCC (114 days) versus the A/COPD (288 days) group. Gender-adjusted Forced expiratory volume in the first second of exhalation/Forced vital capacity (FEV₁/FVC) ratios, residual volume%, and Diffusion capacity for carbon monoxide (DLCO%) were significantly higher in UCC versus A/COPD, whereas the response to bronchodilators of FEV₁, FVC and residual volumes were significantly greater in A/COPD patients. Conclusions: Clinical characteristics differentiating UCC from A/COPD could accelerate recognition of UCC diagnosis especially in the subspecialty setting where patients with these disorders are referred.

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

Background

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

Study design and methods

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

Results

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

Interpretation

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

Herbal Medicine Maekmundong-Tang on Patients with Nonspecific Chronic Cough: Study Protocol for a Double-Blind, Randomized Controlled Clinical Trial

As the treatment of nonspecific chronic cough with conventional medications that treat cough according to the cause is limited, Maekmundong-tang (comprising Liriopis seu Ophiopogonis Tuber, Pinelliae Tuber, Oryzae Semen, Zizyphi Fructus, Ginseng Radix, and Glycyrrhizae Radix et Rhizoma) has been used empirically in the clinical setting of East Asian traditional medicine. This study is the first to explore the feasibility, preliminary effect, safety, and cost-effectiveness of Maekmundong-tang for nonspecific chronic cough. This study protocol is that of a double-blind, randomized, active-controlled, parallel-group clinical trial for comparing Maekmundong-tang with Saengmaek-san (comprising Liriopis seu Ophiopogonis Tuber, Ginseng Radix, and Schisandrae Fructus), a Korean national health insurance-covered herbal medicine for cough. A total of 30 nonspecific chronic cough patients will participate and receive the assigned herbal medicine for 6 weeks, and clinical parameters will be assessed at weeks 0 (baseline), 3 (midterm assessment), 6 (primary endpoint), 9, and 24 (follow-up). Study feasibility outcomes, including recruitment, adherence, and completion rates, will be assessed. Preliminary effects on cough severity, frequency, and quality of life will be evaluated using outcome measures, such as the Cough Symptom Score, Cough Visual Analog Scale, and the Leicester Cough Questionnaire. Adverse events and laboratory tests will be monitored for safety evaluation, and exploratory economic evaluations will be conducted. The results will provide evidence of Maekmundong-tang in the treatment of nonspecific chronic cough.

The role of smoking and alcohol in mediating the effect of gastroesophageal reflux disease on lung cancer: A Mendelian randomization study

Observational studies have suggested a positive association between gastroesophageal reflux disease and lung cancer, but due to the existence of confounders, it remains undetermined whether gastroesophageal reflux disease (GERD) has a causal association with lung cancer. Therefore, Mendelian randomization (MR) analyses were applied to investigate the relationship between the two conditions. Two-sample Mendelian randomization analysis was utilized with summary genetic data from the European Bioinformatics Institute (602,604 individuals) and International Lung Cancer Consortium, which provides information on lung cancer and its histological subgroups. Furthermore, we used two-step Mendelian randomization and multivariable Mendelian randomization to estimate whether smoking initiation (311,629 cases and 321,173 controls) and alcohol intake frequency (n = 462,346) mediate any effect of gastroesophageal reflux disease on lung cancer risk. The Mendelian randomization analyses indicated that gastroesophageal reflux disease was associated with and significantly increased the risk of lung cancer (ORIVW = 1.35, 95% CI = 1.18-1.54; p = 1.36 × 10-5). Smoking initiation and alcohol intake frequency mediated 35% and 3% of the total effect of gastroesophageal reflux disease on lung cancer, respectively. The combined effect of these two factors accounted for 60% of the total effect. In conclusion, gastroesophageal reflux disease is associated with an increased risk of lung cancer, and interventions to reduce smoking and alcohol intake may reduce the incidence of lung cancer.

Multi-Modal Point-of-Care Diagnostics for COVID-19 Based on Acoustics and Symptoms

BACKGROUND

The COVID-19 pandemic has highlighted the need to invent alternative respiratory health diagnosis methodologies which provide improvement with respect to time, cost, physical distancing and detection performance. In this context, identifying acoustic bio-markers of respiratory diseases has received renewed interest.

OBJECTIVE

In this paper, we aim to design COVID-19 diagnostics based on analyzing the acoustics and symptoms data. Towards this, the data is composed of cough, breathing, and speech signals, and health symptoms record, collected using a web-application over a period of twenty months.

METHODS

We investigate the use of time-frequency features for acoustic signals and binary features for encoding different health symptoms. We experiment with use of classifiers like logistic regression, support vector machines and long-short term memory (LSTM) network models on the acoustic data, while decision tree models are proposed for the symptoms data.

RESULTS

We show that a multi-modal integration of inference from different acoustic signal categories and symptoms achieves an area-under-curve (AUC) of 96.3%, a statistically significant improvement when compared against any individual modality ([Formula: see text]). Experimentation with different feature representations suggests that the mel-spectrogram acoustic features performs relatively better across the three kinds of acoustic signals. Further, a score analysis with data recorded from newer SARS-CoV-2 variants highlights the generalization ability of the proposed diagnostic approach for COVID-19 detection.

CONCLUSION

The proposed method shows a promising direction for COVID-19 detection using a multi-modal dataset, while generalizing to new COVID variants.

COVID-19 assessment using HMM cough recognition system

This paper is a part of our contributions to research on the ongoing COVID-19 pandemic around the world. This research aims to use Hidden Markov Model (HMM) based automatic speech recognition system to analyze the cough signal and determine whether the signal belongs to a sick or healthy speaker. We built a configurable model by using HMMs, Gaussian Mixture Models (GMMs), Mel frequency spectral coefficients (MFCCs) and a cough corpus collected from healthy and sick voluntary speakers. Our proposed method is able to classify dry cough with sensitivity from 85.86% to 91.57%, differentiate the dry cough, and cough COVID-19 symptom with specificity from 5 to 10%. The obtained results are very encouraging to enrich our corpus with more data and increase the performance of our diagnostic system.

Ivy leaves extract EA 575 in the treatment of cough during acute respiratory tract infections: meta-analysis of double-blind, randomized, placebo-controlled trials

Ivy leaves extracts have been used successfully to treat acute cough, and data from well-controlled trials is accumulating. We present a meta-analysis of two double-blind, randomized, placebo-controlled trials. Patients with acute respiratory tract infection (ARTI) received ivy leaves dry extract EA 575 (n = 228) or placebo (n = 162) for 7 days, followed by a 7-day period without treatment. The main efficacy outcome was the Bronchitis Severity Score (BSS). Individual patient data meta-analyses were performed using mixed models for repeated measures, analysis of covariance and logistic ordinal regression. Significant BSS differences between EA 575 and placebo occurred already after 2 days and increased until treatment end, with BSS reductions of 8.6 ± 0.2 and 6.2 ± 0.2 (marginal means ± SEM; p < 0.001). The score reduction for placebo after 7 days was comparable to that for EA 575 after 4 days. In the EA 575 group, the proportion of cough-free patients was 18.1% at treatment end and 56.2% at end of follow-up, compared to 9.3% and 25.6% for placebo, respectively. Adverse event rates for EA 575 and placebo were comparable. EA 575 reduces effectively the intensity of acute cough associated with ARTIs and leads to a significant acceleration of recovery. No safety signals were observed.

The Diagnosis and Time of Onset of Voice Disorders in Patients with Chronic Cough

OBJECTIVES

Chronic cough is a complaint of up to 46% of patients referred to specialist clinics. Patients with cough often report hoarseness at the time of the cough diagnosis. When the cough fails to resolve with standard medications, referrals to other specialists including otolaryngologists are made. This is the first study to report the specific diagnosis and length of time it took to obtain a specific voice disorder diagnosis in patients with chronic cough.

STUDY DESIGN

Case Series METHODS: The charts of 105 patients referred to the Loma Linda Voice and Swallowing Center were reviewed. The first complaint of cough and/or hoarseness and the specific voice disorder diagnosis following otolaryngologic evaluation were identified. Voice disorders were divided into neurogenic or other/functional disorders and common comorbidities were identified. Statistical analysis between diagnostic groups, gender, and age were obtained.

RESULTS

The specific voice disorders in the cohort were identified. There was a high prevalence of neurogenic voice disorders (n = 85, 81%). There were significant relationships between chronic cough and the two most common neurogenic voice disorders, vocal fold paresis and vocal fold atrophy. The average length of time between complaint of hoarseness and the specific voice disorder diagnosis was 32.3 months. Most patients (86%) complained of voice problems after diagnosis of chronic cough. A significant association was found in prevalence of asthma (OR = 4.52, P = 0.02) and dyspnea (OR = 4.24, P = 0.02) in the cohort who presented first with voice complaints and later developed chronic cough.

CONCLUSIONS

There is a high incidence of neurogenic voice disorders accompanying patients with chronic cough. Understanding the relationship between chronic cough and hoarseness provides the clinician with specific diagnostic information in the treatment of both disorders.

GERD-related chronic cough: Possible mechanism, diagnosis and treatment

GERD, or gastroesophageal reflux disease, is a prevalent medical condition that affects millions of individuals throughout the world. Chronic cough is often caused by GERD, and chronic cough caused by GER is defined as GERD-related chronic cough (GERC). It is still unclear what the underlying molecular mechanism behind GERC is. Reflux theory, reflex theory, airway allergies, and the novel mechanism of esophageal motility disorders are all assumed to be linked to GERC. Multichannel intraluminal impedance combined with pH monitoring remains the gold standard for the diagnosis of GERC, but is not well tolerated by patients due to its invasive nature. Recent discoveries of new impedance markers and new techniques (mucosal impedance testing, salivary pepsin, real-time MRI and narrow band imaging) show promises in the diagnosis of GERD, but the role in GERC needs further investigation. Advances in pharmacological treatment include potassium-competitive acid blockers and neuromodulators (such as Baclofen and Gabapentin), prokinetics and herbal medicines, as well as non-pharmacological treatments (such as lifestyle changes and respiratory exercises). More options have been provided for the treatment of GERC other than acid suppression therapy and anti-reflux surgery. In this review, we attempt to review recent advances in GERC mechanism, diagnosis, and subsequent treatment options, so as to provide guidance for management of GERC.

Particle Swarm Optimization-Based Extreme Learning Machine for COVID-19 Detection

COVID-19 (coronavirus disease 2019) is an ongoing global pandemic caused by severe acute respiratory syndrome coronavirus 2. Recently, it has been demonstrated that the voice data of the respiratory system (i.e., speech, sneezing, coughing, and breathing) can be processed via machine learning (ML) algorithms to detect respiratory system diseases, including COVID-19. Consequently, many researchers have applied various ML algorithms to detect COVID-19 by using voice data from the respiratory system. However, most of the recent COVID-19 detection systems have worked on a limited dataset. In other words, the systems utilize cough and breath voices only and ignore the voices of the other respiratory system, such as speech and vowels. In addition, another issue that should be considered in COVID-19 detection systems is the classification accuracy of the algorithm. The particle swarm optimization-extreme learning machine (PSO-ELM) is an ML algorithm that can be considered an accurate and fast algorithm in the process of classification. Therefore, this study proposes a COVID-19 detection system by utilizing the PSO-ELM as a classifier and mel frequency cepstral coefficients (MFCCs) for feature extraction. In this study, respiratory system voice samples were taken from the Corona Hack Respiratory Sound Dataset (CHRSD). The proposed system involves thirteen different scenarios: breath deep, breath shallow, all breath, cough heavy, cough shallow, all cough, count fast, count normal, all count, vowel a, vowel e, vowel o, and all vowels. The experimental results demonstrated that the PSO-ELM was capable of attaining the highest accuracy, reaching 95.83%, 91.67%, 89.13%, 96.43%, 92.86%, 88.89%, 96.15%, 96.43%, 88.46%, 96.15%, 96.15%, 95.83%, and 82.89% for breath deep, breath shallow, all breath, cough heavy, cough shallow, all cough, count fast, count normal, all count, vowel a, vowel e, vowel o, and all vowel scenarios, respectively. The PSO-ELM is an efficient technique for the detection of COVID-19 utilizing voice data from the respiratory system.

Physiology and pathophysiology of human airway mucus

The mucus clearance system is the dominant mechanical host defense system of the human lung. Mucus is cleared from the lung by cilia and airflow, including both two-phase gas-liquid pumping and cough-dependent mechanisms, and mucus transport rates are heavily dependent on mucus concentration. Importantly, mucus transport rates are accurately predicted by the gel-on-brush model of the mucociliary apparatus from the relative osmotic moduli of the mucus and periciliary-glycocalyceal (PCL-G) layers. The fluid available to hydrate mucus is generated by transepithelial fluid transport. Feedback interactions between mucus concentrations and cilia beating, via purinergic signaling, coordinate Na+ absorptive vs Cl- secretory rates to maintain mucus hydration in health. In disease, mucus becomes hyperconcentrated (dehydrated). Multiple mechanisms derange the ion transport pathways that normally hydrate mucus in muco-obstructive lung diseases, e.g., cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD), non-CF bronchiectasis (NCFB), and primary ciliary dyskinesia (PCD). A key step in muco-obstructive disease pathogenesis is the osmotic compression of the mucus layer onto the airway surface with the formation of adherent mucus plaques and plugs, particularly in distal airways. Mucus plaques create locally hypoxic conditions and produce airflow obstruction, inflammation, infection, and, ultimately, airway wall damage. Therapies to clear adherent mucus with hydrating and mucolytic agents are rational, and strategies to develop these agents are reviewed.

Characteristics of different asthma phenotypes associated with cough: a prospective, multicenter survey in China

Background

Asthma is a heterogeneous disease with variable symptoms, which presents with cough either as the sole or predominant symptom with or without wheezing. We compared the clinical and pathophysiological characteristics of cough predominant asthma (CPA), cough variant asthma (CVA) and classic asthma (CA) in order to determine any differential phenotypic traits.

Methods

In 20 clinics across China, a total of 2088 patients were finally recruited, including 327 CVA, 1041 CPA and 720 CA patients. We recorded cough and wheezing visual analogue scale, Leicester cough questionnaire (LCQ) and asthma control test scores. Fractional exhaled nitric oxide (FeNO), induced sputum cell counts, and capsaicin cough challenge were also measured and compared.

Results

CPA patients more frequently presented with cough as the initial symptom, and laryngeal symptoms (p < 0.001), had less symptoms related with rhinitis/sinusitis and gastroesophageal reflux (p < 0.05) than CA patients. Comorbidities including rhinitis and gastroesophageal reflux were similar, while the proportion of COPD and bronchiectasis was higher in CA patients. There were no differences in FeNO levels, sputum eosinophil and neutrophil counts, FEV1 (%pred) decreased from CVA to CPA to CA patients (p < 0.001). Cough sensitivity was higher in CVA and CPA compared to CA (p < 0.001), and was positively correlated with LCQ scores.

Conclusions

CVA, CPA and CA can be distinguished by the presence of laryngeal symptoms, cough sensitivity and airflow obstruction. Asthma-associated chronic cough was not associated with airway inflammation or comorbidities in our cohort.

Trial registration The Chinese Clinical Trial Registration Center, ChiCTR-POC-17011646, 13 June 2017

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02104-8.

Challenges and Opportunities of Deep Learning for Cough-Based COVID-19 Diagnosis: A Scoping Review

In the past two years, medical researchers and data scientists worldwide have focused their efforts on containing the pandemic of coronavirus disease 2019 (COVID-19). Deep learning models have been proven to be capable of efficient medical diagnosis and prognosis in cancer, common lung diseases, and COVID-19. On the other hand, artificial neural networks have demonstrated their potential in pattern recognition and classification in various domains, including healthcare. This literature review aims to report the state of research on developing neural network models to diagnose COVID-19 from cough sounds to create a cost-efficient and accessible testing tool in the fight against the pandemic. A total of 35 papers were included in this review following a screening of the 161 outputs of the literature search. We extracted information from articles on data resources, model structures, and evaluation metrics and then explored the scope of experimental studies and methodologies and analyzed their outcomes and limitations. We found that cough is a biomarker, and its associated information can determine an individual's health status. Convolutional neural networks were predominantly used, suggesting they are particularly suitable for feature extraction and classification. The reported accuracy values ranged from 73.1% to 98.5%. Moreover, the dataset sizes ranged from 16 to over 30,000 cough audio samples. Although deep learning is a promising prospect in identifying COVID-19, we identified a gap in the literature on research conducted over large and diversified data sets.

The disease burden and quality of life of chronic cough patients in South Korea and Taiwan

Background

Chronic cough (CC) is a common condition, but the burden of CC in general populations remains largely unknown. This study aims to investigate the disease prevalence and burden among community-based CC patients in South Korea and Taiwan, using structured tools.

Methods

A population-based cross-sectional study uses data from the 2020 South Korea and Taiwan National Health and Wellness Survey (NHWS) as well as a CC survey conducted between January–February 2020 and March–April 2020, respectively. Health outcome measures included health-related quality of life (HRQoL), health state utilities, work productivity and activity impairment (WPAI), and measurement of depression, anxiety, and insomnia among CC patients.

Results

The weighted lifetime and 12-month prevalence of CC was 6.20% and 4.34% in South Korea, and 8.27% and 5.55% in Taiwan. Compared to matched non-CC controls, CC patients reported poorer HRQoL (SF-12v2) in terms of physical component summary (PCS) score (South Korea: 47.69 ± 7.68 vs. 50.08 ± 7.29; Taiwan: 48.58 ± 7.15 vs. 50.50 ± 7.30) and mental component summary (MCS) score (44.15 ± 8.85 vs. 46.28 ± 8.50; 42.44 ± 7.78 vs. 44.60 ± 8.08), health state utilities EQ-5D index (0.73 ± 0.23 vs. 0.82 ± 0.16; 0.82 ± 0.13 vs. 0.86 ± 0.14), and more visits to healthcare professionals (7.80 vs. 4.61; 6.09 vs. 4.20) (p < 0.05). In terms of WPAI, CC patients reported higher impairments in presenteeism (32.8% vs. 21.0%; 25.9% vs. 19.4%), total work productivity (36.2% vs. 22.3%; 27.7% vs. 20.6%), and total activity (34.2% vs. 23.2%; 27.7% vs. 20.3%) than non-CC controls (p < 0.001). CC patients in South Korea and Taiwan experienced anxiety, depression, and insomnia more than non-CC controls. Poorer health outcomes were associated with the severity of CC. Patients with severe CC (visual analogue scale [VAS]>4) in both nations reported lower PCS score (45.80 vs. 49.48; 47.41 vs. 49.22) and higher absenteeism (8.5% vs. 3.6%; 5.5% vs. 1.8%) than patients with mild CC (VAS≤4) (p < 0.05).

Conclusions

The findings revealed that the disease burden of CC in general populations of South Korea and Taiwan is considerable with a negative impact on the overall quality of life, social and work life, and psychological comorbidities and is significantly associated with increased severity of the CC. There is an unmet need for further treatment interventions for CC patients to relieve the burden of CC in both nations.

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.

Diagnostic value of reflux episodes in gastroesophageal reflux-induced chronic cough: a novel predictive indicator

Background

Multichannel intraluminal impedance and pH-monitoring (MII-pH) is an essential testing modality for gastroesophageal reflux-induced chronic cough (GERC), while the existing diagnostic criteria still have some inherent defects. This study aimed to explore the diagnostic value of a direct and objective index, reflux episodes, and related parameters in MII-pH in different types of GERC.

Methods

Patients with chronic cough suspected of gastroesophageal reflux disease who successfully received MII-pH were enrolled. The differences in MII-pH parameters were analyzed among patients with different etiologies and the predictive diagnostic value of reflux episodes and related parameters were analyzed in patients with GERC, acid GERC, and non-acid GERC, and compared with existing diagnostic criteria.

Results

A total of 190 patients with suspected GERC who underwent MII-pH were enrolled; 131 of these patients were finally diagnosed with GERC. When the reflux episodes were used to diagnose GERC, the area under the curve (AUC) was 0.684; when the acid reflux episodes and the ratio of acid reflux episodes were used to diagnose acid GERC, the AUCs were 0.769 and 0.854; when the non-acid reflux episodes and the ratio of non-acid reflux episodes were used to diagnose non-acid GERC, the AUCs were 0.735 and 0.705, respectively. When the non-acid reflux episodes > 58 and the proportion of non-acid reflux episodes > 68.18% were used alone or in combination to diagnose non-acid GERC, their diagnostic value was significantly better than SAP or SI (all ps < 0.05).

Conclusion

The number of reflux episodes has a good diagnostic value for GERC, especially in the diagnosis of non-acid GERC.

[Acute and chronic cough - differential diagnosis and treatment]

Cough is a frequent reason for consultation in the general practitioner's office. Most of the time, the symptom is harmless and self-limiting, as in the case of a banal cold cough, for example - however, serious diseases such as malignancies can also be the cause. Evaluation is therefore not always easy. This article presents a targeted and appropriate approach and discusses which treatments are recommended and effective.Acute and chronic cough are differentiated according to the duration of symptoms (up to 8 weeks/longer than 8 weeks). The most common cause of acute cough is a self-limiting viral infection of the upper respiratory tract; the most important differential diagnosis is community-acquired pneumonia. If there are no defined warning signs (red flags), the history and clinical examination are sufficient to establish the diagnosis in the case of an acute cough; medication is not necessary. In the case of a chronic cough, a chest X-ray is usually ordered and then further investigations are carried out in accordance with the most probable suspected diagnosis; probationary therapies are an important part of the workup. Coughs that are refractory to treatment or unexplained require individualised treatment (pharmacological, including off-label, non-pharmacological) and regular re-evaluation.

Tracheobronchial-esophageal reflex initiates esophageal hypersensitivity and aggravates cough hyperreactivity in guinea pigs with esophageal acid infusion

Esophageal-tracheobronchial reflex is considered the main mechanism underlying cough due to gastroesophageal reflux, and is associated with esophageal hypersensitivity. We hypothesized that tracheobronchial-esophageal reflex may also exist, and may be related to esophageal hypersensitivity. To test this hypothesis, conscious and ether-anesthetized guinea pigs were subjected to repetitive capsaicin inhalation to establish models of cough (conscious) and cough-free (anesthetized) airway injury, respectively, followed by esophageal acid infusion. Recurrent capsaicin inhalation induced similar cough hyperreactivity to inhaled capsaicin after esophageal acid infusion in guinea pigs with cough and guinea pigs with cough-free airway injury during recurrent capsaicin inhalation. Cough hyperreactivity, along with overexpression of transient receptor potential vanilloid 1 (TRPV1) receptors in esophageal mucosa and in nerve fibers of tracheal mucosa of guinea pigs were blocked by pretreatment with esophageal infusion of capsazepine, but not atropine. Thus, recurrent airway nociceptive stimuli induce esophageal hyperreactivity via a tracheobronchial-esophageal reflex mediated by vagal C afferents expressing TRPV1, and enhance cough due to reflux.

Cough hypersensitivity and chronic cough

Chronic cough is globally prevalent across all age groups. This disorder is challenging to treat because many pulmonary and extrapulmonary conditions can present with chronic cough, and cough can also be present without any identifiable underlying cause or be refractory to therapies that improve associated conditions. Most patients with chronic cough have cough hypersensitivity, which is characterized by increased neural responsivity to a range of stimuli that affect the airways and lungs, and other tissues innervated by common nerve supplies. Cough hypersensitivity presents as excessive coughing often in response to relatively innocuous stimuli, causing significant psychophysical morbidity and affecting patients' quality of life. Understanding of the mechanisms that contribute to cough hypersensitivity and excessive coughing in different patient populations and across the lifespan is advancing and has contributed to the development of new therapies for chronic cough in adults. Owing to differences in the pathology, the organs involved and individual patient factors, treatment of chronic cough is progressing towards a personalized approach, and, in the future, novel ways to endotype patients with cough may prove valuable in management.

The Evolving Clinical Practice of Chronic Cough

Chronic cough, defined as a cough lasting for greater than 8 weeks, accounts for a substantial number of primary care and specialist consultations in the United States. Although cough can arise from a myriad number of serious respiratory diseases, attention has traditionally focused on diagnosing and treating gastroesophageal reflux, upper airway cough syndrome, and eosinophilic airway inflammation (asthma and nonasthmatic eosinophilic bronchitis) in patients with normal chest imaging. The newly described paradigm and entity of cough hypersensitivity syndrome (CHS) becomes useful when the etiology of cough remains elusive or when the cough remains refractory despite appropriate therapy for underlying causes. We present an update on the evolving understanding of refractory chronic cough and/or unexplained chronic cough as manifestations of laryngeal hypersensitivity and CHS. This includes a focus on understanding the pathophysiology underlying current and novel therapeutics for CHS, while also ensuring that common causes of chronic cough continue to be evaluated and treated in a systematic multidisciplinary manner.

Safety, Pharmacodynamics, and Pharmacokinetics of P2X3 Receptor Antagonist Eliapixant (BAY 1817080) in Healthy Subjects: Double-Blind Randomized Study

Background and Objective

There is no licensed treatment for refractory chronic cough; off-label therapies have limited efficacy and can produce adverse effects. Excessive adenosine triphosphate signaling via P2X3 receptors is implicated in refractory chronic cough, and selective P2X3 receptor antagonists such as eliapixant (BAY 1817080) are under investigation. The objective of the study was to investigate the safety and tolerability of ascending repeated oral doses of eliapixant in healthy volunteers.

Methods

We conducted a repeated-dose, double-blind, randomized, placebo-controlled study in 47 healthy male individuals. Subjects received repeated twice-daily ascending oral doses of eliapixant (10, 50, 200, and 750 mg) or placebo for 2 weeks. The primary outcome was frequency and severity of adverse events. Other outcomes included pharmacokinetics and evaluation of taste disturbances, which have occurred with the less selective P2X3 receptor antagonist gefapixant.

Results

Peak plasma concentrations of eliapixant were reached 3–4 h after administration of the first and subsequent doses. With multiple dosing, steady-state plasma concentrations were reached after ~ 6 days, and plasma concentrations predicted to achieve ≥ 80% P2X3 receptor occupancy (the level required for efficacy) were reached at 200 and 750 mg. Increases in plasma concentrations with increasing doses were less than dose proportional. After multiple dosing, mean plasma concentrations of eliapixant showed low peak–trough fluctuations and were similar for 200- and 750-mg doses. Eliapixant was well tolerated with a low incidence of taste-related adverse events.

Conclusions

Eliapixant (200 and 750 mg) produced plasma concentrations that cover the predicted therapeutic threshold over 24 h, with good safety and tolerability. These results enabled eliapixant to progress to clinical trials in patients with refractory chronic cough.

Clinical Trial Registration

Clinicaltrials.gov: NCT03310645 (initial registration: 16 October, 2017).

Supplementary Information

The online version contains supplementary material available at 10.1007/s40262-022-01126-1.

There are few effective treatments for patients with a long-term (chronic) cough. It is thought that chronic cough is caused by nerves becoming oversensitive, wrongly causing a cough when there is no need. We tested a new drug called eliapixant in 47 healthy men. Eliapixant reduces the excessive nerve signaling responsible for chronic cough. We looked for side effects of eliapixant and measured how it behaves in the body. In particular we looked for side effects relating to the sense of taste because gefapixant, a similar drug to eliapixant, can affect taste. Participants took one of four eliapixant doses or a placebo twice daily for 2 weeks. The highest levels of eliapixant in the blood were seen 3–4 h after taking the drug, and stable concentrations were seen after about 6 days. At the two highest doses, eliapixant reached concentrations in the body that should be high enough to work in patients with chronic cough. Side effects were generally similar between eliapixant and placebo. Taste-related side effects were mild and went away without needing treatment. The positive results of this study meant that eliapixant could be tested in patients with chronic cough.

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

Background

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

Methods

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

Results

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

Conclusion

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

Chronic cough in asthma is associated with increased airway inflammation, more comorbidities, and worse clinical outcomes

Background: Cough is often the most prominent and intractable symptom reported by patients with asthma, but few studies have explored the characteristics of patients with asthma and with chronic cough (CC) in a real-world setting. Methods: In a prospective cohort study, patients ages ≥ 18 years with stable asthma were consecutively recruited at the West China Hospital, Sichuan University. The patients were classified as having asthma with CC (the CC group) or asthma with non-CC (the non-CC group) after 3 months of optimized asthma therapy according to standard guidelines. Multidimensional assessment was performed at baseline, followed by a 12-month follow-up to assess asthma exacerbations. Results: Of 323 patients with asthma, 127 patients were assigned to the CC group and 196 patients were assigned to the non-CC group. The participants with CC were older and had more airflow obstruction; worse asthma control and quality of life; increased airway inflammation; upper respiratory tract infection as a trigger; and more comorbidities, such as psychological dysfunction, rhinitis, chronic obstructive pulmonary disease, and bronchiectasis. They reported greater work productivity loss and daily activity impairment, and increased moderate-to-severe exacerbations. Conclusion: The participants with asthma and with CC had a significant disease burden, with increased exacerbations, health-care utilization, and impaired work productivity and daily activity. These observations indicated potential clinical implications in patients with asthma and with CC, and call for more attention to this aspect of asthma.

[Acute Cough in Adult Patients]

Background

Acute cough (< 8 weeks) is a frequent complaint in family practice consultations. The most common cause are respiratory infections. The Guideline "Acute and chronic cough" of the German College of General Practitioners and Family Physicians (DEGAM) was updated in 2021 and contains recommendations for an evidence-based approach for the management of acute cough in primary care.

Methods

The guideline has been updated in accordance with the findings of a systematic search of the literature for international guidelines and systematic reviews. All recommendations were developed by an interdisciplinary guideline committee and agreed by formal consensus.

Results

History-taking, exclusion of red flags and a physical examination are the basis of diagnostic evaluation. If an acute, uncomplicated bronchitis is likely, no laboratory tests, sputum diagnostics, or chest x-rays should be performed, and antibiotics should not be administered. Evidence based strategies to avoid antibiotic therapy (delayed prescribing, shared decision making, point-of-care-tests) can be used. There is inadequate evidence for the efficacy of antitussive or expectorant drugs against acute cough. The state of the evidence for phytotherapeutic agents is heterogeneous; clinical importance is minimal. COVID-19 should currently be considered in cases of acute respiratory symptoms. If specific symptoms or red flags occur, further diagnoses in the context of acute cough such as community-acquired pneumonia, influenza disease and exacerbations of chronic respiratory diseases (bronchial asthma, COPD) should be taken into consideration.

Conclusions

These evidence-based recommendations are intended to reduce the use of antibiotics to treat colds and acute bronchitis, for which they are not indicated. Further clinical trials of symptomatic treatments for cough should be performed in order to extend the evidence base.

Application of unsupervised deep learning algorithms for identification of specific clusters of chronic cough patients from EMR data

BACKGROUND

Chronic cough affects approximately 10% of adults. The lack of ICD codes for chronic cough makes it challenging to apply supervised learning methods to predict the characteristics of chronic cough patients, thereby requiring the identification of chronic cough patients by other mechanisms. We developed a deep clustering algorithm with auto-encoder embedding (DCAE) to identify clusters of chronic cough patients based on data from a large cohort of 264,146 patients from the Electronic Medical Records (EMR) system. We constructed features using the diagnosis within the EMR, then built a clustering-oriented loss function directly on embedded features of the deep autoencoder to jointly perform feature refinement and cluster assignment. Lastly, we performed statistical analysis on the identified clusters to characterize the chronic cough patients compared to the non-chronic cough patients.

RESULTS

The experimental results show that the DCAE model generated three chronic cough clusters and one non-chronic cough patient cluster. We found various diagnoses, medications, and lab tests highly associated with chronic cough patients by comparing the chronic cough cluster with the non-chronic cough cluster. Comparison of chronic cough clusters demonstrated that certain combinations of medications and diagnoses characterize some chronic cough clusters.

CONCLUSIONS

To the best of our knowledge, this study is the first to test the potential of unsupervised deep learning methods for chronic cough investigation, which also shows a great advantage over existing algorithms for patient data clustering.

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

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

Respiratory symptoms and use of dust-control measures in New Zealand construction workers – A cross-sectional study

Dust-exposed construction workers have an increased risk of respiratory symptoms, but the efficacy of dust-control measures remains unclear. This study compared respiratory symptoms, using a modified European Community Respiratory Health Survey questionnaire, between construction workers (n = 208) and a reference group of bus drivers and retail workers (n = 142). Within the construction workers, we assessed the effect of collective (on-tool vacuum/’wet-cut’ systems) and personal (respirators) exposure controls on symptom prevalence. Logistic regression assessed differences between groups, adjusted for age, ethnicity, and smoking status. Construction workers were more likely to cough with phlegm at least once a week (OR 2.4, 95% CI 1.2–4.7) and cough with phlegm ≥3 months/year for ≥2 years (OR 2.8, CI 1.2–7.0), but they had similar or fewer asthma symptoms. Construction workers who had worked for 11–20 years reported more cough/phlegm symptoms (OR 5.1, 1.7–15.0 for cough with phlegm ≥3 months/year for ≥2 years) than those who had worked <10 years (OR 1.9, 0.6–5.8), when compared to the reference group. Those who used ‘wet-cut’ methods reported less cough with phlegm, although the evidence for this association was weak (OR 0.4, CI 0.2–1.1 for cough with phlegm at least once a week); use of on-tool extraction showed a similar trend. No associations between respiratory protective equipment-use and symptoms were found. In conclusion, construction workers reported more symptoms suggestive of bronchitis, particularly those employed in the industry for >10 years. Use of collective dust exposure controls might protect against these symptoms, but this requires confirmation in a larger study.

Soft Exoskeleton Mimics Human Cough for Assisting the Expectoration Capability of SCI Patients

OBJECTIVE

This paper describes the design of a bionic soft exoskeleton and demonstrates its feasibility for assisting the expectoration function rehabilitation of patients with spinal cord injury (SCI).

METHODS

A human-robot coupling respiratory mechanic model is established to mimic human cough, and a synergic inspire-expire assistance strategy is proposed to maximize the peak expiratory flow (PEF), the key metric for promoting cough intensity. The negative pressure module of the exoskeleton is a soft "iron lung" using layer-jamming actuation. It assists inspiration by increasing insufflation to mimic diaphragm and intercostal muscle contraction. The positive pressure module exploits soft origami actuators for assistive expiration; it pressures human abdomen and bionically "pushes" the diaphragm upward.

RESULTS

The maximum increase in PEF ratios for mannequins, healthy participants, and patients with SCI with robotic assistance were 57.67%, 278.10%, and 124.47%, respectively. The soft exoskeleton assisted one tetraplegic SCI patient to cough up phlegm successfully.

CONCLUSION

The experimental results suggest that the proposed soft exoskeleton is promising for assisting the expectoration ability of SCI patients in everyday life scenarios.

SIGNIFICANCE

The proposed soft exoskeleton is promising for advancing the application field of rehabilitation exoskeletons from motor functions to respiratory functions.

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

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

Quantitative evaluation of disease severity in connective tissue disease-associated interstitial lung disease by dual-energy computed tomography

Background

High-resolution computed tomography (HRCT) is recommended diagnosing and monitoring connective tissue disease-associated interstitial lung disease (CTD-ILD). Quantitative computed tomography has the potential to precisely assess the radiological severity of CTD-ILD, but has still been under study.

Objective

To investigate whether dual-energy computed tomography (DECT), a novel quantitative technique, can be used for quantitative severity assessment in CTD-ILD.

Methods

This cross sectional study recruited adult CTD-ILD patients who underwent DECT scans from the ICE study between October 2019 and November 2021. DECT parameters, including effective atomic number (Z_eff), lung (lobe) volume, and monochromatic CT number (MCTN) of each lung lobe, were evaluated. CTD-ILD was classified into extensive CTD-ILD and limited CTD-ILD by staging algorithm using combined forced vital capacity (FVC)%predicted and total extent of ILD (TEI) on CT. Dyspnea, cough, and life quality were scored by Borg dyspnea score, Leicester cough questionnaire (LCQ), and short-form 36 health survey questionnaire (SF-36), respectively.

Results

There was a total of 147 patients with DECT scans enrolled. Higher Z_eff value (3.104 vs 2.256, p < 0.001), higher MCTN (− 722.87 HU vs − 802.20 HU, p < 0.001), and lower lung volume (2309.51cm³ vs 3475.21cm³, p < 0.001) were found in extensive CTD-ILD compared with limited CTD-ILD. DECT parameters had significant moderate correlations with FVC%predicted (|r|= 0.542–0.667, p < 0.01), DLCO%predicted (|r|= 0.371–0.427, p < 0.01), and TEI (|r|= 0.485–0.742, p < 0.01). Receiver operating characteristic (ROC) analysis indicated MCTN averaged over the whole lung had the best performance for extensive CTD-ILD discrimination (AUC = 0.901, cut-off: − 762.30 HU, p < 0.001), with a sensitivity of 82.1% and a specificity of 85.4%. The Z_eff value was the independent risk factor for dyspnea (OR = 3.644, 95% CI: 1.846–7.192, p < 0.001) and cough (OR = 3.101, 95% CI: 1.528–6.294, p = 0.002), and lung volume significantly contributed to the mental component summary (MCS) in SF-36 (standardized β = 0.198, p < 0.05).

Conclusions

DECT can be applied to evaluate the severity of CTD-ILD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-01972-4.

The interrelationship of chronic cough and depression: a prospective population-based study

Background

Chronic cough is a debilitating medical condition that is often complicated by psychomorbidities such as depressive symptoms. Nevertheless, little is known about the impact of chronic cough on the risk of developing depression. Therefore, we investigated the association between chronic cough and prevalent, incident and recurrent depression in a population-based sample of middle-aged and older persons.

Methods

Within the Rotterdam Study, a population-based cohort, we defined chronic cough as reporting daily coughing for ⩾3 months. Depression was assessed using the Center for Epidemiologic Studies Depression scale, clinical interviews and medical records. Associations between chronic cough and depression were determined with linear, logistic and Cox regression analyses.

Results

The study included 5877 participants (mean±sd age 72±8 years, 59% female) who contributed 37 287 person-years of follow-up. At baseline, participants with chronic cough reported more depressive symptoms (adjusted standardised mean difference 0.15, 95% CI 0.07–0.22) compared to those without chronic cough. Over time, chronic cough was associated with an increased risk of depression in participants with a history of depression (hazard ratio (HR) 1.45, 95% CI 1.13–1.84), but not in those without a history of depression (HR 0.91, 95% CI 0.68–1.22).

Conclusions

Adults with chronic cough have a disproportionate burden of depressive symptoms and an increased risk of recurrent depression. This highlights the importance of screening for depression in patients with chronic cough.

Adults with chronic cough have a disproportionate burden of depressive symptoms and are more likely to suffer recurrent depression, highlighting the need for screening for depression in individuals with chronic coughhttps://bit.ly/3sPvYTd

Clinical and Inflammatory Characteristics of the Chinese APAC Cough Variant Asthma Cohort

Background

The AtyPical Asthma in China (APAC) cohort is a multi-center prospective, observational cohort set-up to investigate the clinical, pathophysiological features, prognosis, and mechanisms of cough variant asthma (CVA).

Objectives

To present the characteristics of newly physician-diagnosed adults with CVA (n = 328) compared to mild-moderate classic asthma (CA, n = 206).

Methods and Main Results

CVA subjects showed a higher proportion of female (67.1 vs. 55.3%, P = 0.0084), abnormal laryngopharyngeal sensations (71 vs. 51%, p < 0.0001) than CA, but presented with near normal spirometry and higher methacholine PD20-FEV1 values [4.2 (1, 8.6) vs. 0.8 (0.4, 4.7), P < 0.0001]. Lower fractional exhaled nitric oxide (FENO) levels [38.5 (19.8, 72.5) vs. 53. (28.5, 92.2), P = 0.0019], blood eosinophil counts [0.2 (0.1, 0.4) vs. 0.3 (0.2, 0.5), P = 0.0014], and sputum eosinophils [2.3 (0.3, 8.0) vs. 12.2 (2, 34.5), p < 0.0001] were found in CVA. Despite lower total serum IgE levels in CVA, there was similar proportion of atopy in both groups. The prevalence of cough in CA was 86.4%, while CVA reported more severe cough on Visual Analog Scale, Cough Evaluation Test, and Leicester Cough Questionnaire, similar anxiety and depression scores but better asthma control scores as reflected by Asthma Control Test compared to CA. No correlation was found between cough assessment outcomes and sputum eosinophil count, blood eosinophil count, FENO, spirometry variables, or PD20-FEV1.

Conclusion

Cough variant asthma is distinctive from classic asthma in regard to clinical features, lung function, and airway inflammation. Quality of life is badly impaired as well in spite of better asthma control scores.

Clinical Practice Guideline: Chronic Cough

BACKGROUND

Chronic cough, i.e., cough lasting longer than eight weeks, affects approximately 10% of the population and is a common reason for outpatient medical consultation. Its differential diagnosis is extensive, and it is generally evaluated in poorly structured fashion with a variety of diagnostic techniques. The German Clinical Practice Guideline on Acute and Chronic Cough was updated in 2021 and contains a description of the recommended stepwise, patient-centered, and evidence-based procedure for the management of chronic cough.

METHODS

The guideline has been updated in accordance with the findings of a systematic search of the literature for international guidelines and systematic reviews. All recommendations were developed in an interdisciplinary manner and agreed upon by formal consensus. The target group consists of adult patients with cough.

RESULTS

History-taking, after the exclusion of red flags, should include questioning about smoking status, medications, and relevant present and past illnesses (COPD, asthma). Subsequent diagnostic testing should include a chest x-ray and pulmonary function tests. If the patient is taking an ACE inhibitor, a test of drug discontinuation can be carried out first. Radiologically detected pulmonary masses or evidence of rare diseases (interstitial lung diseases, bronchiectasis) are an indication for chest CT or for direct referral to an appropriate specialist. If the imaging studies and pulmonary function tests are normal, the patient is most likely suffering from a disease entity that can be treated empirically, such as upper airway cough syndrome or cough variant asthma. Any patient with an unexplained or refractory cough must receive proper patient education; individual therapeutic trials of physiotherapeutic or speechtherapeutic methods are possible, as is the off-label use of gabapentin or morphine.

CONCLUSION

Chronic cough should be evaluated according to an established diagnostic algorithm in collaboration with specialists. Treatments such as inhaled corticosteroids should be tested exhaustively in accordance with the guidelines, and the possibility of multiple causes as well as the role of patient compliance should be kept in mind before a diagnosis of unexplained or intractable cough is assigned.

Symptomatic Features and Factors Associated With Do-Not-Resuscitate Consent in Advanced Cancer Patients Admitted to Palliative Care Ward

This study aimed to conduct a retrospective cross-sectional study to investigate the prevalence of symptoms and symptom clusters on sociodemographic and disease characteristics, as well as factors associated with Do-Not-Resuscitate (DNR) consent. Advanced cancer patients were enrolled between 2018 and 2020 with available data. Demographic and clinical data were obtained for analysis from Hospital Information System (HIS) in China. Symptom clusters were extracted by hierarchical cluster analysis. Chi-square test and multiple logistic regression were conducted to investigate the prevalence characteristics of symptoms and influencing factors of DNR consent, respectively. 798 advanced cancer patients were enrolled. The most prevalent symptoms were pain (93%), anorexia (36.5%), and sleep disorders (34.2%). High heart rate was associated with poor performance status and more symptoms. Three clusters were extracted: fatigue-related, respiratory-circulatory system, and digestive system symptom clusters. The incidence of symptoms was statistically significant in age, gender, education level, residence, BMI, performance status, distress score, ADL, and primary pain level. The DNR signature rate was 15.5%. Female, distant metastasis, in-ward rescue, and appearance of dyspnea were independent influencing factors of DNR signature.Chinese hospitalized cancer patients had more symptoms burden that were influenced by various demographic characteristics, especially pain and fatigue-related symptoms. Concerning the trajectory of vital signs is important among advanced cancer patients. The DNR signature rate was lower and our finding indicating an urgency to accurately assess the prognosis and give more palliative care education to enhance DNR rates and early signing in Chinese context.

Small Airway Dysfunction in Cough Variant Asthma: Prevalence, Clinical, and Pathophysiological Features

Introduction: Small airway dysfunction (SAD) commonly presents in patients with classic asthma, which is associated with airway inflammation, disease severity, and asthma control. However, the prevalence of SAD, its relationship with cough severity and airway inflammation, and its development after antiasthmatic treatment in patients with cough variant asthma (CVA) need to be clarified. This study aimed to investigate the prevalence of SAD and its relationship with clinical and pathophysiological characteristics in patients with CVA and the change in small airway function after antiasthmatic treatment.

Methods: We retrospectively analyzed 120 corticosteroid-naïve patients with CVA who had finished a standard questionnaire and relevant tests in a specialist cough clinic, such as cough visual analog scale (VAS), differential cells in induced sputum, fractional exhaled nitric oxide (FeNO) measurement, spirometry, and airway hyper-responsiveness. Information of 1-year follow-up was recorded in a part of patients who received complete cough relief after 2 months of treatment. SAD was defined as any two parameters of maximal mid-expiratory flow (MMEF)% pred, forced expiratory flow at 50% of forced vital capacity (FEF50%) pred, and forced expiratory flow at 75% of forced vital capacity (FEF75%) pred measuring <65%.

Results: SAD occurred in 73 (60.8%) patients with CVA before treatment. The patients with SAD showed a significantly longer cough duration (24.0 vs. 6.0, p = 0.031), a higher proportion of women (78.1 vs. 59.6%, p = 0.029), older mean age (41.9 vs. 35.4, p = 0.005), and significantly lower forced expiratory volume in 1 s (FEV₁%) pred, FEV₁/FVC, MMEF% pred, FEF50% pred, FEF75% pred, PEF% pred, and PD20 (all p < 0.01) as compared with patients without SAD. There were no significant differences in cough VAS, sputum eosinophils count, FeNO, and TIgE level between patients with SAD and those without SAD. Among 105 patients who completed 2 months of antiasthmatic treatment and repeatedly experienced spirometry measurement, 57 (54.3%) patients still had SAD, despite a significant improvement in cough VAS, sputum eosinophils, FeNO, FEF50% pred, and PEF% pred (all p < 0.01). As compared with patients without SAD, patients with SAD showed no significant differences in the relapse rate (50.0 vs. 41.9%, p = 0.483) and wheeze development rate (10.4 vs. 0%, p = 0.063) during the follow-up.

Conclusions: Small airway dysfunction occurred in over half of patients with CVA and persisted after short-term antiasthmatic treatment, which showed distinctive clinical and pathophysiological features.

Effect of Continuous Positive Airway Pressure on Chronic Cough in Patients with Obstructive Sleep Apnea and Concomitant Gastroesophageal Reflux

BACKGROUND

Obstructive sleep apnea (OSA) and/or gastroesophageal reflux (GER) may be the contributors to chronic cough in patients with OSA and concomitant GER. This study aimed to explore whether continuous positive airway pressure (CPAP), antireflux treatment and lifestyle modifications improve chronic cough in patients with OSA and concomitant GER.

METHODS

Patients with OSA and concomitant GER who also experienced chronic cough were enrolled, and were divided into two groups. Patients who were treated with general treatment (antireflux treatment and lifestyle modifications) as the control group, and patients who were treated with CPAP and general treatment as the treatment group. Effects of different treatments on chronic cough were assessed, and the association among chronic cough, GER and OSA was evaluated by Pearson's correlation analysis.

RESULTS

The Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale were better in the treatment group after 1 week of treatment; further, the improvement became stronger with the duration of therapy. The gastroesophageal reflux disease questionnaire, visual analog scale (VAS) for cough, and daytime and nighttime cough symptom scores significantly improved in both groups after treatment, whereas this improvement was more significant in the treatment group. Significant associations between the apnea-hypopnea index (AHI) and VAS, weak acid reflux and VAS, and weak acid reflux and AHI were observed.

CONCLUSION

CPAP improved the symptoms of chronic cough and GER in patients with OSA and concomitant GER. AHI and weak acid reflux may be important factors affecting the therapeutic effect of chronic cough in patients with OSA and concomitant GER.

Prevalence of chronic cough and patient characteristics in adults in Spain: A population-based cross-sectional survey

Background

Chronic cough (CC) represents a significant health burden. This study assessed the prevalence of CC (defined as per international guidelines as cough duration >8 weeks) in Spanish adults and compared characteristics between CC and non-CC cohorts.

Methods

CC cohorts were compiled using data from adult respondents to the 2020 Spanish cross-sectional online National Health and Wellness Survey (NHWS). Using propensity scores, respondents experiencing CC during their lifetime and the previous 12 months were matched 3:1 to respondents without CC and their health characteristics were compared. The number of Spanish adults affected with CC was estimated using weighted CC prevalence.

Results

CC during their lifetime or the previous 12 months was experienced by 579 (8.2%) and 389 (5.5%) of 7074 NHWS respondents, of whom 233 (38.5%) and 171 (44.0%), respectively, had physician-diagnosed CC. Based on weighted prevalence rates, lifetime and 12-month CC were estimated to affect ≈3.3 million and ≈2.2 million Spanish adults, respectively. Relative to the non-CC cohort, the 12-month CC cohort consistently demonstrated poorer health status, poorer mental health, greater healthcare utilization, and lower productivity at work and home.

Conclusion

This study contributes novel data regarding the prevalence of CC in Spain, suggests that CC is underdiagnosed, and reflects that CC and related comorbidities inflict a significant health burden in the affected population.

Clinical characteristics in adult patients with somatic cough syndrome

Objective:

The data in regard of the clinical characteristics and diagnosis of somatic cough syndrome in adults were limited. The aim of this study was to fill that gap.

Methods:

This was a retrospective analysis of patients with somatic cough syndrome. We described clinical characteristics of adult patients with somatic cough syndrome.

Results:

Twenty-three somatic cough syndrome patients were identified in 543 adult patients with chronic cough. Psychiatric disorder of these patients was identified as anxiety (n = 8), obsessive-compulsive (n = 7), somatoform (n = 6), depression (n = 3), and cognitive bias (n = 1). Twelve patients showed abnormal results of investigations related with common causes of chronic cough, including gastroesophageal reflux, sputum eosinophilia, bronchial hyper-responsiveness, or signs of sinusitis but did not respond to the treatments directed to those conditions. All these patients were ever misdiagnosed as other causes of chronic cough. Compared to 520 non-somatic cough syndrome patients, patients with somatic cough syndrome were younger (32 (29.0–43.0) vs 42.0 (32.0–55.0) years, p = 0.013), longer disease duration (48.0 (19.5–102.0) vs 24.0 (9.0–72.0) months, p = 0.037), more common in dry cough (100% vs 57.6%, p < 0.001), and lower proportion of nocturnal cough (13.0% vs 40.2%, p = 0.009). Common cold (60.9%) was the most common initial trigger of cough and itchy throat (60.9%) was the most common accompanying symptom in patients with somatic cough syndrome. Notably, there were similar distribution in cough triggers and accompanying symptoms between two groups.

Conclusion:

In spite of much higher proportion of dry cough and smaller proportion of nocturnal cough, adult patients with somatic cough syndrome show similar clinical characteristics with other chronic cough patients, in regard of cough triggers, accompanying symptoms as well as abnormal results of investigations, which should be an important reason for misdiagnosis of somatic cough syndrome. Psychiatric disorder should be addressed in clinical management of chronic cough.

Burden and impact of chronic cough in UK primary care: a dataset analysis

OBJECTIVE

Chronic cough (CC) is a debilitating respiratory symptom, now increasingly recognised as a discrete disease entity. This study evaluated the burden of CC in a primary care setting.

DESIGN

Cross-sectional, retrospective cohort study.

SETTING

Discover dataset from North West London, which links coded data from primary and secondary care. The index date depicted CC persisting for ≥8 weeks and was taken as a surrogate for date of CC diagnosis.

PARTICIPANTS

Data were extracted for individuals aged ≥18 years with a cough persisting ≥8 weeks or cough remedy prescription, between Jan 2015 and Sep 2019.

MAIN OUTCOME MEASURES

Demographic characteristics, comorbidities and service utilisation cost, including investigations performed and treatments prescribed were determined.

RESULTS

CC was identified in 43 453 patients from a total cohort of 2 109 430 (2%). Median (IQR) age was 64 years (41-87). Among the cohort, 31% had no recorded comorbidities, 26% had been given a diagnosis of asthma, 17% chronic obstructive pulmonary disease, 12% rhinitis and 15% reflux. Prevalence of CC was greater in women (57%) and highest in the 65-74 year age range. There was an increase in the number of all investigations performed in the 12 months before and after the index date of CC diagnosis, and in particular for primary care chest X-ray and spirometry which increased from 6535 to 12 880 and from 5791 to 8720, respectively. This was accompanied by an increase in CC-associated healthcare utilisation costs.

CONCLUSION

One-third of individuals had CC in the absence of associated comorbidities, highlighting the importance of recognising CC as a condition in its own right. Overall outpatient costs increased in the year after the CC index date for all comorbidities, but varied significantly with age. Linked primary-care datasets may enable earlier detection of individuals with CC for specialist clinic referral and targeted treatment.