Phenotypes of cough in children: A latent class analysis.

INTRODUCTION: Distinguishing phenotypes among children with cough helps understand underlying causes. Using a statistical data-driven approach, we aimed to identify and validate cough phenotypes based on measurable traits, physician diagnoses, and prognosis. METHODS: We used data from the Swiss Paediatric Airway Cohort and included 531 children aged 5-16 years seen in outpatient clinics since 2017. We included children with any parent-reported cough (i.e. cough without a cold, cough at night, cough more than other children, or cough longer than 4 weeks) without current wheeze. We applied latent class analysis to identify phenotypes using nine symptoms and characteristics and selected the best model using the Akaike information criterion. We assigned children to the most likely phenotype and compared the resulting groups for parental atopy history, comorbidities, spirometry, fractional exhaled nitric oxide (FeNO), skin prick tests and specific IgE, physician diagnoses, and 1-year prognosis. RESULTS: We identified four cough phenotypes: non-specific cough (26%); non-allergic infectious and night cough with snoring and otitis (4%); chronic allergic dry night cough with snoring (9%); and allergic non-infectious cough with rhino-conjunctivitis (61%). Children with the allergic phenotype often had family or personal history of atopy and asthma diagnosis. FeNO was highest for the allergic phenotype [median 17.9 parts per billion (ppb)] and lowest for the non-allergic infectious phenotype [median 7.0 parts per billion (ppb)]. Positive allergy test results differed across phenotypes (p < .001) and were most common among the allergic (70%) and least common among the non-specific cough (31%) phenotypes. Subsequent wheeze was more common among the allergic than the non-specific phenotype. CONCLUSION: We identified four clinically relevant cough phenotypes with different prognoses. Although we excluded children with current wheeze, most children with cough belonged to allergy-related phenotypes.

Predictors of asthma control differ from predictors of asthma attacks in children: The Swiss Paediatric Airway Cohort.

BACKGROUND: It is unclear if predictors of asthma attacks are the same as those of asthma symptom control in children. OBJECTIVE: We evaluated predictors for these two outcomes in a clinical cohort study. METHODS: The Swiss Paediatric Airway Cohort (SPAC) is a multicentre prospective clinical cohort of children referred to paediatric pulmonologists. This analysis included 516 children (5-16 years old) diagnosed with asthma. At baseline, we collected sociodemographic information, symptoms, personal and family history and environmental exposures from a parental baseline questionnaire, and treatment and test results from hospital records. Outcomes were assessed 1 year later by parental questionnaire: asthma control in the last 4 weeks as defined by GINA guidelines, and asthma attacks defined as any unscheduled visit for asthma in the past year. We used logistic regression to identify and compare predictors for suboptimal asthma control and asthma attacks. RESULTS: At follow-up, 114/516 children (22%), reported suboptimal asthma control, and 114 (22%) an incident asthma attack. Only 37 (7%) reported both. Suboptimal asthma control was associated with poor symptom control at baseline (e.g. ≥1 night wheeze/week OR: 3.2; 95% CI: 1.7-6), wheeze triggered by allergens (2.2; 1.4-3.3), colds (2.3; 1.4-3.6) and exercise (3.2; 2-5), a more intense treatment at baseline (2.4; 1.3-4.4 for Step 3 vs. 1), history of preschool (2.6; 1.5-4.4) and persistent wheeze (2; 1.4-3.2), and exposure to tobacco smoke (1.7; 1-2.6). Incident asthma attacks were associated with previous episodes of severe wheeze (2; 1.2-3.3) and asthma attacks (2.8; 1.6-5 for emergency care visits), younger age (0.8; 0.8-0.9 per 1 year) and non-Swiss origin (0.3; 0.2-0.5 for Swiss origin). Lung function, exhaled nitric oxide (FeNO) and allergic sensitization at baseline were not associated with control or attacks. CONCLUSION: Children at risk of long-term suboptimal asthma control differ from those at risk of attacks. Prediction tools and preventive efforts should differentiate these two asthma outcomes.

Characteristics of Severe Asthma Patients and Predictors of Asthma Control in the Swiss Severe Asthma Registry.

BACKGROUND: Asthma is a chronic airway disease, affecting over 300 million people worldwide. 5-10% of patients suffer from severe asthma and account for 50% of asthma-related financial burden. Availability of real-life data about the clinical course of severe asthma is insufficient. OBJECTIVES: The aims of this study were to characterize patients with severe asthma in Switzerland, enrolled in the Swiss Severe Asthma Registry (SSAR), and evaluate predictors for asthma control. METHOD: A descriptive characterisation of 278 patients was performed, who were prospectively enrolled in the registry until January 2022. Socio-demographic variables, comorbidities, diagnostic values, asthma treatment, and healthcare utilisation were evaluated. Groups of controlled and uncontrolled asthma according to the asthma control test were compared. RESULTS: Forty-eight percent of patients were female and the mean age was 55.8 years (range 13-87). The mean body mass index (BMI) was 27.4 kg/m2 (±6). 10.8% of patients were current smokers. Allergic comorbidities occurred in 54.3% of patients, followed by chronic rhinosinusitis (46.4%) and nasal polyps (34.1%). According to the ACT score, 54.7% had well controlled, 16.2% partly controlled and 25.9% uncontrolled asthma. The most common inhalation therapy was combined inhaled corticosteroids/long-acting ß2-agonists (78.8%). Biologics were administered to 81.7% of patients and 19.1% received oral steroids. The multivariable analysis indicated that treatment with biologics was positively associated with asthma control whereas higher BMI, oral steroids, exacerbations, and COPD were negative predictors for asthma control. CONCLUSION: Biologics are associated with improved control in severe asthma. Further studies are required to complete the picture of severe asthma in order to provide improved care for those patients.

[COPD : a still neglected condition]. / BPCO : une maladie encore négligée.

Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung disorder with a complex clinical picture. The diagnosis may be difficult at times, as COPD may develop insidiously and remain unnoticed for a long time. Therefore, general practitioners play a central role in early detection of disease. Suspected COPD may be confirmed by further investigations in collaboration with a pulmonologist. The most recent GOLD guideline defines three COPD risk groups (A-B-E) which should guide the personalized treatment concept. General practitioners are crucial for implementing non-pharmacological measures such as smoking cessation, regular exercise, vaccinations, and patient self-management education. However, this also underlines the challenges to implement the GOLD recommendations in daily practice.

La BPCO est une maladie hétérogène avec un tableau clinique complexe. Le diagnostic n'est pas toujours facile à évoquer, car elle peut se développer insidieusement et passer longtemps inaperçue. Les médecins de premier recours (MPR) jouent donc un rôle central dans le diagnostic précoce. La suspicion de BPCO peut être confirmée en collaboration avec un pneumologue par des examens fonctionnels respiratoires avant l'instauration d'un traitement médicamenteux. Les nouvelles recommandations GOLD, publiées en 2022 définissent trois groupes de risques pour la BPCO (A-B-E). Les MPR sont importants pour la mise en œuvre de mesures accompagnant le traitement (arrêt du tabac, activité physique régulière, vaccinations, éducation thérapeutique). Mais cela souligne également les exigences élevées de la mise en œuvre des recommandations GOLD dans la pratique quotidienne.*.

[Novelties in the Treatment of Asthma]. / Nouveautés dans la prise en charge de l'asthme.

For general practitioners there have been important novelties in the treatment of asthma due to recent modifications of the international guidelines from Global Initiative for Asthma (GINA). In Step 1, use of short-acting beta2-agonists (SABA) without concomitant inhaled corticosteroids (ICS) as controller is no longer recommended for lack of efficacy and safety reasons. Instead, low dose ICS-formoterol as needed is recommended. In Step 5, in patients with severe uncontrolled asthma GINA recommends targeted biologic therapies like interleukin antibodies. Asthma patients presenting simultaneously with symptoms of chronic obstructive pulmonary disease (COPD) should receive treatment containing ICS. Independent of the current corona pandemic, GINA recommendations stay in place.

Les nouvelles recommandations GINA (Global Initiative for Asthma) modifient radicalement la prise en charge des patients asthmatiques pour le médecin de premier recours. Dans l'asthme léger (palier 1 GINA), les bêta2-agonistes à courte durée d'action (SABA) seuls comme traitement de secours ne sont plus recommandés au profit d'une association de corticostéroïdes inhalés (CSI) faiblement dosés avec un bronchodilatateur à longue durée d'action à début d'action rapide (formotérol). Dans l'asthme sévère non contrôlé (palier 5 GINA), l'objectif est d'éviter la corticothérapie orale au profit de thérapies biologiques ciblées (par exemple, anticorps anti-interleukine). Un traitement contenant des CSI doit être maintenu chez les asthmatiques même si une BPCO est associée. Les recommandations GINA ne sont pas modifiées par les conditions actuelles de pandémie.

Diagnosis of asthma in children: findings from the Swiss Paediatric Airway Cohort.

INTRODUCTION: Diagnosing asthma in children remains a challenge because respiratory symptoms are not specific and vary over time. AIM: In a real-life observational study, we assessed the diagnostic accuracy of respiratory symptoms, objective tests and two paediatric diagnostic algorithms (proposed by the Global Initiative for Asthma (GINA) and the National Institute for Health and Care Excellence (NICE)) in the diagnosis of asthma in school-aged children. METHODS: We studied children aged 5-17 years who were referred consecutively to pulmonary outpatient clinics for evaluation of suspected asthma. Symptoms were assessed by parental questionnaire. The investigations included specific IgE measurement or skin prick tests, measurement of exhaled nitric oxide fraction (F eNO), spirometry, body plethysmography and bronchodilator reversibility (BDR). Asthma was diagnosed by paediatric pulmonologists based on all available data. We assessed diagnostic accuracy of symptoms, tests and diagnostic algorithms by calculating sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under the curve (AUC). RESULTS: Among 514 participants, 357 (70%) were diagnosed with asthma. The combined sensitivity and specificity was highest for any wheeze (sensitivity=75%, specificity=65%), dyspnoea (sensitivity=56%, specificity=76%) and wheeze triggered by colds (sensitivity=58%, specificity=78%) or by exercise (sensitivity=55%, specificity=74%). Of the diagnostic tests, the AUC was highest for specific total airway resistance (sRtot; AUC=0.73) and lowest for the residual volume (RV)/total lung capacity (TLC) ratio (AUC=0.56). The NICE algorithm had sensitivity=69% and specificity=67%, whereas the GINA algorithm had sensitivity=42% and specificity=90%. CONCLUSION: This study confirms the limited usefulness of single tests and existing algorithms for the diagnosis of asthma. It highlights the need for new and more appropriate evidence-based guidance.

Electronic monitoring of adherence to inhaled corticosteroids: an essential tool in identifying severe asthma in children.

International guidelines recommend that severe asthma can only be diagnosed after contributory factors, including adherence, have been addressed. Accurate assessment of adherence is difficult in clinical practice. We hypothesised that electronic monitoring in children would identify nonadherence, thus delineating the small number with true severe asthma.Asthmatic children already prescribed inhaled corticosteroids were prospectively recruited and persistence of adherence assessed using electronic monitoring devices. Spirometry, airway inflammation and asthma control were measured at the start and end of the monitoring period.93 children (62 male; median age 12.4 years) were monitored for a median of 92 days. Median (range) monitored adherence was 74% (21-99%). We identified four groups: 1) good adherence during monitoring with improved control, 24% (likely previous poor adherence); 2) good adherence with poor control, 18% (severe therapy-resistant asthma); 3) poor adherence with good control, 26% (likely overtreated); and 4) poor adherence with poor control, 32%. No clinical parameter prior to monitoring distinguished these groups.Electronic monitoring is a useful tool for identifying children in whom a step up in treatment is indicated. Different approaches are needed in those who are controlled when adherent or who are nonadherent. Electronic monitoring is essential in a paediatric severe asthma clinic.

The ADO index as a predictor of two-year mortality in general practice-based chronic obstructive pulmonary disease cohorts.

BACKGROUND: Existing prediction models for mortality in chronic obstructive pulmonary disease (COPD) patients have not yet been validated in primary care, which is where the majority of patients receive care. OBJECTIVES: Our aim was to validate the ADO (age, dyspnoea, airflow obstruction) index as a predictor of 2-year mortality in 2 general practice-based COPD cohorts. METHODS: Six hundred and forty-six patients with COPD with GOLD (Global Initiative for Chronic Obstructive Lung Disease) stages I-IV were enrolled by their general practitioners and followed for 2 years. The ADO regression equation was used to predict a 2-year risk of all-cause mortality in each patient and this risk was compared with the observed 2-year mortality. Discrimination and calibration were assessed as well as the strength of association between the 15-point ADO score and the observed 2-year all-cause mortality. RESULTS: Fifty-two (8.1%) patients died during the 2-year follow-up period. Discrimination with the ADO index was excellent with an area under the curve of 0.78 [95% confidence interval (CI) 0.71-0.84]. Overall, the predicted and observed risks matched well and visual inspection revealed no important differences between them across 10 risk classes (p = 0.68). The odds ratio for death per point increase according to the ADO index was 1.50 (95% CI 1.31-1.71). CONCLUSIONS: The ADO index showed excellent prediction properties in an out-of-population validation carried out in COPD patients from primary care settings.

An open-label study examining the effect of pharmacological treatment on mannitol- and exercise-induced airway hyperresponsiveness in asthmatic children and adolescents with exercise-induced bronchoconstriction.

BACKGROUND: Mannitol- and exercise bronchial provocation tests are both used to diagnose exercise-induced bronchoconstriction. The study aim was to compare the short-term treatment response to budesonide and montelukast on airway hyperresponsiveness to mannitol challenge test and to exercise challenge test in children and adolescents with exercise-induced bronchoconstriction. METHODS: Patients were recruited from a paediatric asthma rehabilitation clinic located in the Swiss Alps. Individuals with exercise-induced bronchoconstriction and a positive result in the exercise challenge test underwent mannitol challenge test on day 0. All subjects then received a treatment with 400 µg budesonide and bronchodilators as needed for 7 days, after which exercise- and mannitol-challenge tests were repeated (day 7). Montelukast was then added to the previous treatment and both tests were repeated again after 7 days (day 14). RESULTS: Of 26 children and adolescents with exercise-induced bronchoconstriction, 14 had a positive exercise challenge test at baseline and were included in the intervention study. Seven of 14 (50%) also had a positive mannitol challenge test. There was a strong correlation between airway responsiveness to exercise and to mannitol at baseline (r = 0.560, p = 0.037). Treatment with budesonide and montelukast decreased airway hyperresponsiveness to exercise challenge test and to a lesser degree to mannitol challenge test. The fall in forced expiratory volume in one second during exercise challenge test was 21.7% on day 0 compared to 6.7% on day 14 (p = 0.001) and the mannitol challenge test dose response ratio was 0.036%/mg on day 0 compared to 0.013%/mg on day 14 (p = 0.067). CONCLUSION: Short-term treatment with an inhaled corticosteroid and an additional leukotriene receptor antagonist in children and adolescents with exercise-induced bronchoconstriction decreases airway hyperresponsiveness to exercise and to mannitol.

The clinical features of asthma exacerbations in early-onset and eosinophilic late-onset asthma may differ significantly.

Over 20 years ago, the concept of asthma control was created and appropriate measurement tools were developed and validated. Loss of asthma control can lead to an exacerbation. Years ago, the term "clinically significant asthma exacerbation" was introduced to define when a loss of control is severe enough to declare it an asthma exacerbation. This term is also used by health insurances to determine when an exacerbation is eligible for reimbursement of biologics in clinical practice, however, it sometimes becomes apparent that a clear separation between loss of "asthma control" and an exacerbation is not always possible. In this review, we attempt to justify why exacerbations in early allergic asthma and adult eosinophilic asthma can differ significantly and why this is important in clinical practice as well as when dealing with health insurers.

Standardization of Reporting Obstructive Airway Disease in Children: A National Delphi Process.

BACKGROUND: Pediatric pulmonologists report asthma and obstructive bronchitis in medical records in a variety of ways, and there is no consensus for standardized reporting. OBJECTIVE: We investigated which diagnostic labels and features pediatric pulmonologists use to describe obstructive airway disease in children and aimed to reach consensus for standardized reporting. METHODS: We obtained electronic health records from 562 children participating in the Swiss Pediatric Airway Cohort from 2017 to 2018. We reviewed the diagnosis section of the letters written by pediatric pulmonologists to referring physicians and extracted the terms used to describe the diagnosis. We grouped these terms into diagnostic labels (eg, asthma) and features (eg, triggers) using qualitative thematic framework analysis. We also assessed how frequently the different terms were used. Results were fed into a modified Delphi process to reach consensus on standardized reporting. RESULTS: Pediatric pulmonologists used 123 different terms to describe the diagnosis, which we grouped into 6 diagnostic labels and 17 features. Consensus from the Delphi process resulted in the following recommendations: (i) to use the diagnostic label "asthma" for children older than 5 years and "obstructive bronchitis" or "suspected asthma" for children younger than 5 years; (ii) to accompany the diagnosis with relevant features: diagnostic certainty, triggers, symptom control, risk of exacerbation, atopy, treatment adherence, and symptom perception. CONCLUSION: We found great heterogeneity in the reporting of obstructive airway disease among pediatric pulmonologists. The proposed standardized reporting will simplify communication among physicians and improve quality of research based on electronic health records.

[COPD - An Underestimated Disease]. / COPD ­ eine unterschätzte Erkrankung.

COPD - An Underestimated Disease Abstract: Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung condition with a complex clinical picture. The diagnosis is not easy to make because COPD can develop insidiously and remain unnoticed for a long time. Therefore, general practitioners play a central role in the early detection of the disease. Suspected COPD can be confirmed by special examinations in collaboration with pulmonologists. The new GOLD guideline defines three COPD risk groups (A-B-E) which should guide the personalized treatment concept. A short- or long-acting bronchodilator (SAMA/SABA or LAMA/LABA) is recommended for group A, and a dual long-acting bronchodilator therapy (LABA+LAMA) is recommended for group B and E. In case of blood eosinophilia (≥300 cells/µl) and/or recent hospitalization for COPD exacerbation, triple therapy (LABA+LAMA+ICS) is recommended. General practitioners are important in implementing non-pharmacological measures (smoking cessation, regular exercise, vaccinations, patient selfmanagement education). However, this also underlines the high demands of the implementation of the GOLD guideline in daily practice.

Treatment Decisions in Children With Asthma in a Real-Life Clinical Setting: The Swiss Paediatric Airway Cohort.

BACKGROUND: Asthma treatment should be modified according to symptom control and future risk, but there are scarce data on what drives treatment adjustments in routine tertiary care. OBJECTIVE: We studied factors that drive asthma treatment adjustment in pediatric outpatient clinics. METHODS: We performed a cross-sectional analysis of the Swiss Paediatric Airway Cohort, a clinical cohort of 0- to 16-year-old children seen by pediatric pulmonologists. We collected information on diagnosis, treatment, lung function, and FeNO from hospital records; and on symptoms, sociodemographic, and environmental factors from a parental questionnaire. We used reported symptoms to classify asthma control and categorized treatment according to the 2020 Global Initiative for Asthma guidelines. We used multivariable logistic regression to study factors associated with treatment adjustment (step-up or down vs no change). RESULTS: We included 551 children diagnosed with asthma (mean age, 10 years; 37% female). At the clinical visit, most children were prescribed Global Initiative for Asthma step 3 (35%). Compared with previsit treatment, 252 children remained on the same step (47%), 227 were stepped up (42%), and 58 were stepped down (11%). Female sex (adjusted odds ratio [aOR] = 1.61; 95% confidence interval [CI], 1.05-2.47), poor asthma control (aOR = 3.08; 95% CI, 1.72-5.54), and lower FEV1 Z-score (aOR = 0.70; 95% CI, 0.56-0.86 per one Z-score increase) were independently associated with treatment step-up, and low FeNO (aOR = 2.34; 95% CI, 1.23-4.45) was associated with treatment step-down, with marked heterogeneity between clinics. CONCLUSIONS: In this tertiary care real-life study, we identified main drivers for asthma treatment adjustment. These findings may help improve both asthma management guidelines and clinical practice.

Inflammatory bowel disease and the lung in paediatric patients.

The prevalence of inflammatory bowel disease (IBD) has increased over the past 20 years. Pulmonary involvement in paediatric IBD is rare but may be missed since the spectrum of symptoms is broad and mimics other diseases. The most important differential diagnoses of pulmonary manifestations of IBD are infections and therapy-related side-effects. There is no gold standard to diagnose respiratory manifestations in children with IBD. Diagnostic tests should be chosen according to history and clinical presentation. Treatment of respiratory manifestations of IBD includes inhaled or oral corticosteroids and initiation or step-up of immunomodulatory IBD therapies.

A 3-month period of electronic monitoring can provide important information to the healthcare team to assess adherence and improve asthma control.

In children with difficult asthma, a single period of electronic monitoring can help to assess a patient's adherence and the possible impact of improved adherence on asthma control https://bit.ly/3c3Gj6n.

[Novelties in the Treatment of Asthma]. / Neues in der Asthma-Grundversorgung.

Novelties in the Treatment of Asthma Abstract. For general practitioners there have been important novelties in the treatment of asthma due to recent modifications of the international guidelines from Global Initiative for Asthma (GINA). Step 1 no longer recommends the use of short-acting ß2-agonists (SABA) without concomitant inhaled corticosteroids (ICS) as a controller because of the lack of efficacy and for safety reasons. Instead, low dose ICS-formoterol as needed is recommended. GINA step 5 recommends targeted biologic therapies like interleukin antibodies in patients with severe uncontrolled asthma. Asthma patients presenting simultaneously with symptoms of chronic obstructive pulmonary disease (COPD) should receive treatment containing ICS. Independent of the current corona pandemic, GINA recommendations stay in place. Recent data on prescriptions of SABA and oral corticosteroids (OCS) in Switzerland indicate that they still play an important role in asthma management and that GINA recommendations have not yet been sufficiently implemented into practice.

Diagnosis in children with exercise-induced respiratory symptoms: A multi-center study.

OBJECTIVE: Exercise-induced respiratory symptoms (EIS) are common in childhood and reflect different diseases that can be difficult to diagnose. In children referred to respiratory outpatient clinics for EIS, we compared the diagnosis proposed by the primary care physician with the final diagnosis from the outpatient clinic and described diagnostic tests and treatments. DESIGN: An observational study of respiratory outpatients aged 0-16 years nested in the Swiss Paediatric Airway Cohort (SPAC). PATIENTS: We included children with EIS as the main reason for referral. Information about diagnostic investigations, final diagnosis, and treatment prescribed came from outpatient records. We included 214 children (mean age 12 years, range 2-17, 54% males) referred for EIS. RESULTS: The final diagnosis was asthma in 115 (54%), extrathoracic dysfunctional breathing (DB) in 35 (16%), thoracic DB in 22 (10%), asthma plus DB in 23 (11%), insufficient fitness in 10 (5%), chronic cough in 6 (3%), and other diagnoses in 3 (1%). Final diagnosis differed from referral diagnosis in 115 (54%, 95%-CI 46%-60%). Spirometry, body plethysmography, and exhaled nitric oxide were performed in almost all, exercise-challenge tests in a third, and laryngoscopy in none. 91% of the children with a final diagnosis of asthma were prescribed inhaled medication and 50% of children with DB were referred to physiotherapy. CONCLUSIONS: Diagnosis given at the outpatient clinic often differed from the diagnosis proposed by the referring physician. Diagnostic evaluations, management, and follow-up differed between clinics and diagnostic groups highlighting the need for evidence-based diagnostic guidelines and harmonized procedures for children seen for EIS.

Reported Symptoms Differentiate Diagnoses in Children with Exercise-Induced Respiratory Problems: Findings from the Swiss Paediatric Airway Cohort (SPAC).

BACKGROUND: Exercise-induced breathing problems with similar clinical presentations can have different etiologies. This makes distinguishing common diagnoses such as asthma, extrathoracic and thoracic dysfunctional breathing (DB), insufficient fitness, and chronic cough difficult. OBJECTIVE: We studied which parent-reported, exercise-induced symptoms can help distinguish diagnoses in children seen in respiratory outpatient clinics. METHODS: This study was nested in the Swiss Paediatric Airway Cohort, an observational study of children aged 0 to 17 years referred to pediatric respiratory outpatient clinics in Switzerland. We studied children aged 6 to 17 years and compared information on exercise-induced symptoms from parent-completed questionnaires between children with different diagnoses. We used multinomial regression to analyze whether parent-reported symptoms differed between diagnoses (asthma as base). RESULTS: Among 1109 children, exercise-induced symptoms were reported for 732 (66%) (mean age: 11 years, 318 of 732 [43%] female). Among the symptoms, dyspnea best distinguished thoracic DB (relative risk ratio [RRR]: 5.4, 95% confidence interval [CI]: 1.3-22) from asthma. Among exercise triggers, swimming best distinguished thoracic DB (RRR: 2.4, 95% CI: 1.3-6.2) and asthma plus DB (RRR: 1.8, 95% CI: 0.9-3.4) from asthma only. Late onset of symptoms was less common for extrathoracic DB (RRR: 0.1, 95% CI: 0.03-0.5) and thoracic DB (RRR: 0.4, 95% CI: 0.1-1.2) compared with asthma. Localization of dyspnea (throat vs chest) differed between extrathoracic DB (RRR: 2.3, 95% CI: 0.9-5.8) and asthma. Reported respiration phase (inspiration or expiration) did not help distinguish diagnoses. CONCLUSION: Parent-reported symptoms help distinguish different diagnoses in children with exercise-induced symptoms. This highlights the importance of physicians obtaining detailed patient histories.

Fluctuation-based clustering reveals phenotypes of patients with different asthma severity.

Serial peak expiratory flow (PEF) measurements can identify phenotypes in severe adult asthma, enabling more targeted treatment. The feasibility of this approach in children has not been investigated. Overall, 105 children (67% male, median age 12.4 years) with a range of asthma severities were recruited and followed up over a median of 92 days. PEF was measured twice daily. Fluctuation-based clustering (FBC) was used to identify clusters based on PEF fluctuations. The patients' clinical characteristics were compared between clusters. Three PEF clusters were identified in 44 children with sufficient measurements. Cluster 1 (27% of patients: n=12) had impaired spirometry (mean forced expiratory volume in 1 s (FEV1) 71% predicted), significantly higher exhaled nitric oxide (≥35 ppb) and uncontrolled asthma (asthma control test (ACT) score <20 of 25). Cluster 2 (45%: n=20) had normal spirometry, the highest proportion of difficult asthma and significantly more patients on a high dose of inhaled corticosteroids (≥800 µg budesonide). Cluster 3 (27%: n=12) had mean FEV1 92% predicted, the highest proportion of patients with no bronchodilator reversibility, a low ICS dose (≤400 µg budesonide), and controlled asthma (ACT scores ≥20 of 25). Three clinically relevant paediatric asthma clusters were identified using FBC analysis on PEF measurements, which could improve telemonitoring diagnostics. The method remains robust even when 80% of measurements were removed. Further research will determine clinical applicability.

The Swiss Paediatric Airway Cohort (SPAC).

Chronic respiratory symptoms, such as cough, wheeze and dyspnoea, are common in children; however, most research has, with the exception of a few large-scale clinical cohort studies, been performed in the general population or in small, highly-selected samples. The Swiss Paediatric Airway Cohort (SPAC) is a national, prospective clinical cohort of children and adolescents who visit physicians for recurrent conditions, such as wheeze and cough, and exercise-related respiratory problems. The SPAC is an observational study and baseline assessment includes standardised questionnaires for families and data extracted from hospital records, including results of clinically indicated investigations, diagnoses and treatments. Outcomes are assessed through annual questionnaires, monthly symptom reporting via mobile phone and follow-up visits. The SPAC will address important questions about clinical phenotypes, diagnosis, treatment, and the short- and long-term prognosis of common respiratory problems in children. The cohort currently consists of 347 patients from four major hospitals (Bern, Zurich, Basel and Lucerne), with 70-80 additional patients joining each month. More centres will join and the target sample size is a minimum of 3000 patients. The SPAC will provide real-life data on children visiting the Swiss healthcare system for common respiratory problems and will provide a research platform for health services research and nested clinical and translational studies.