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Dive into the research topics where Adrian Chan is active.

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Featured researches published by Adrian Chan.


The Lancet Respiratory Medicine | 2018

Fractional exhaled nitric oxide as a predictor of response to inhaled corticosteroids in patients with non-specific respiratory symptoms and insignificant bronchodilator reversibility: a randomised controlled trial

David Price; Roland Buhl; Adrian Chan; Daryl Freeman; Elizabeth Gardener; Clifford Godley; Kevin Gruffydd-Jones; Lorcan McGarvey; Ken Ohta; Dermot Ryan; Jörgen Syk; Ngiap Chuan Tan; Tze Lee Tan; Mike Thomas; Sen Yang; Priyanka Raju Konduru; Marcus Ngantcha; Martina Stagno d'Alcontres; Therese S. Lapperre

BACKGROUND Chronic non-specific respiratory symptoms are difficult to manage. This trial aimed to evaluate the association between baseline fractional exhaled nitric oxide (FeNO) and the response to inhaled corticosteroids in patients with non-specific respiratory symptoms. METHODS In this double-blind randomised placebo-controlled trial, we enrolled undiagnosed patients, aged 18-80 years, with cough, wheeze, or dyspnoea and less than 20% bronchodilator reversibility across 26 primary care centres and hospitals in the UK and Singapore. Patients were assessed for 2 weeks before being randomly assigned (1:1) to 4 weeks of treatment with extrafine inhaled corticosteroids (QVAR 80 μg, two puffs twice per day, equivalent to 800 μg per day beclomethasone dipropionate) or placebo. Randomisation was stratified by baseline FeNO measurement: normal (≤25 parts per billion [ppb]), intermediate (>25 tp <40 ppb), and high (≥40 ppb). The primary endpoint was change in Asthma Control Questionnaire (ACQ7) mean score. We used generalised linear modelling to assess FeNO as a predictor of response, estimating an interaction effect between FeNO and treatment on change in ACQ7. We did our primary and secondary analyses in the per-protocol set, which excluded patients with non-completion of the primary endpoint, non-compliance to treatment (ascertained by patient report), and study visits made outside the predefined visit windows. This study is registered on ClinicalTrials.gov, number NCT02294279. FINDINGS Between Feb 4, 2015, and July 12, 2016, we randomly assigned 294 patients to extrafine inhaled corticosteroid treatment (n=148) or placebo (n=146). Following exclusions due to protocol violations, we analysed 214 patients (114 extrafine inhaled corticosteroids and 100 placebo). We observed a significant interaction between baseline FeNO and treatment group for every 10 ppb increase in baseline FeNO, with the change in ACQ7 greater in the extrafine inhaled corticosteroids group than in the placebo group (difference between groups 0·071, 95% CI 0·002 to 0·139; p=0·044). The most common adverse events were nasopharyngitis (18 [12%] patients in the treatment group vs 13 [9%] in the placebo group), infections and infestations (25 [17%] vs 21 [14%]), and respiratory, thoracic, and mediastinal disorders (13 [9%] vs 17 [12%]). INTERPRETATION FeNO measurement is an easy and non-invasive tool to use in clinical practice in patients with non-specific respiratory symptoms to predict response to inhaled corticosteroids. Further research is needed to examine its role in patients with evidence of other airway diseases, such as chronic obstructive pulmonary disease. FUNDING Sponsored by OPRI with partial funding by Circassia and study drugs provided by TEVA.


Allergy | 2017

Long-term future risk of severe exacerbations: Distinct 5-year trajectories of problematic asthma.

Anthony Chau Ang Yii; Jessica Tan; Therese S. Lapperre; Adrian Chan; Su Y. Low; Thun How Ong; Keng L. Tan; Sanjay H. Chotirmall; Peter J. Sterk; Mariko S. Koh

Assessing future risk of exacerbations is an important component of asthma management. Existing studies have investigated short‐ but not long‐term risk. Problematic asthma patients with unfavorable long‐term disease trajectory and persistently frequent severe exacerbations need to be identified early to guide treatment.


Journal of Asthma and Allergy | 2017

Sensitization to Aspergillus species is associated with frequent exacerbations in severe asthma

Ken Junyang Goh; Anthony Chau Ang Yii; Therese S. Lapperre; Adrian Chan; Fook Tim Chew; Sanjay H. Chotirmall; Mariko Siyue Koh

Background Severe asthma is a largely heterogeneous disease with varying phenotypic profiles. The relationship between specific allergen sensitization and asthma severity, particularly in Asia, remains unclear. We aim to study the prevalence of specific allergen sensitization patterns and investigate their association with outcomes in a severe asthma cohort in an Asian setting. Methods We conducted a cross-sectional study of patients receiving step 4 or 5 Global Initiative for Asthma treatment. Univariate and multivariate analyses were performed to assess the association between sensitization to a specific identifiable allergen by skin prick test (SPT) and uncontrolled asthma (defined in our study as the use of ≥2 steroid bursts or hospitalization in the past year, a history of near-fatal asthma or evidence of airflow obstruction on spirometry). Results Two hundred and six severe asthma patients (mean age 45±17 years, 99 [48.1%] male) were evaluated. Of them, 78.2% had a positive SPT to one or more allergens. The most common allergen to which patients were sensitized was house dust mites (Blomia tropicalis, Dermatophagoides pteronyssinus and Dermatophagoides farinae). Also, 11.7% were sensitized to Aspergillus species. On multivariate analysis, Aspergillus sensitization was associated with uncontrolled asthma (odds ratio 6.07, 95% confidence interval 1.80–20.51). In particular, Aspergillus sensitization was independently associated with the use of ≥2 steroid bursts in the past year (odds ratio 3.05, 95% confidence interval 1.04–8.95). No similar associations of uncontrolled asthma with sensitization to any other allergens were found. Conclusion High allergen, specifically Aspergillus sensitization was observed in the Asian population with severe asthma by SPT. Aspergillus sensitization was specifically associated with frequent exacerbations and a greater corticosteroid requirement. An improved understanding of the severe asthma with Aspergillus sensitization phenotype is warranted, which is likely a subgroup of severe asthma with fungal sensitization.


Expert Review of Respiratory Medicine | 2017

Understanding COPD-overlap syndromes

Tuang Yeow Poh; Micheál Mac Aogáin; Adrian Chan; Anthony Chau Ang Yii; Valerie Fei Lee Yong; Pei Yee Tiew; Mariko Siyue Koh; Sanjay H. Chotirmall

ABSTRACT Introduction: Chronic obstructive pulmonary disease accounts for a large burden of lung disease. It can ‘overlap’ with other respiratory diseases including bronchiectasis, fibrosis and obstructive sleep apnea (OSA). While COPD alone confers morbidity and mortality, common features with contrasting clinical outcomes can occur in COPD ‘overlap syndromes’. Areas covered: Given the large degree of heterogeneity in COPD, individual variation to treatment is adopted based on its observed phenotype, which in turn overlaps with features of other respiratory disease states such as asthma. This is coined asthma-COPD overlap syndrome (‘ACOS’). Other examples of such overlapping clinical states include bronchiectasis-COPD (‘BCOS’), fibrosis-COPD (‘FCOS’) and OSA-COPD (‘OCOS’). The objective of this review is to highlight similarities and differences between the COPD-overlap syndromes in terms of risk factors, pathophysiology, diagnosis and potential treatment differences. Expert commentary: As a consequence of COPD overlap syndromes, a transition from the traditional ‘one size fits all’ treatment approach is necessary. Greater treatment stratification according to clinical phenotype using a precision medicine approach is now required. In this light, it is important to recognize and differentiate COPD overlap syndromes as distinct disease states compared to individual diseases such as asthma, COPD, fibrosis or bronchiectasis.


Clinical & Experimental Allergy | 2018

Filaggrin mutations increase allergic airway disease in childhood and adolescence through interactions with eczema and aeroallergen sensitization

Adrian Chan; William Terry; Hongmei Zhang; Wilfried Karmaus; Susan Ewart; John W. Holloway; Graham Roberts; Syed Hasan Arshad

Filaggrin loss‐of‐function (FLG‐LOF) mutations are an established genetic cause of eczema. These mutations have subsequently been reported to increase the risk of aeroallergen sensitization and allergic airway disease. However, it is unclear whether FLG variants require both eczema and aeroallergen sensitization to influence airway disease development long‐term outcomes.


Chest | 2011

A Middle-aged Asthmatic Woman With Unresolving Cough

Adrian Chan; Keng Leong Tan; Angela Takano; Pyng Lee

A 45-year-old woman was referred to the respiratory clinic for productive cough of 6 months’ duration. She was a lifelong nonsmoker and had a history of childhood asthma for which she had not been on regular treatment. CBC count showed a mildly elevated WBC count (10.1 3 10 9 cells/L), and chest radiograph (CXR) was reported to show increased lung density of the left lower zone. She was prescribed a course of macrolide, steroid, and salbutamol inhalers by the general practitioner a month prior to the consultation, but her symptoms did not improve. On further questioning, she remembered an episode of hemoptysis 1 year earlier. There was no weight loss, fever, or night sweats. The patient was afebrile and well nour-


Journal of Thoracic Disease | 2014

Pulmonary alveolar proteinosis

Adrian Chan; Angela Takano; Ann Ling Hsu; Su Ying Low

We report a 68-year-old female who presented with chronic cough and progressive dyspnoea. Computed tomography of the thorax and subsequent bronchoscopy confirmed the diagnosis of pulmonary alveolar proteinosis (PAP), which was treated with whole lung lavage. This case is reported in view of the low incidence of PAP.


BMC Pulmonary Medicine | 2015

Radial endobronchial ultrasound in diagnosing peripheral lung lesions in a high tuberculosis setting

Adrian Chan; Anantham Devanand; Su Ying Low; Mariko Siyue Koh


American Journal of Respiratory and Critical Care Medicine | 2014

Beyond Removal of Endobronchial Foreign Body

Anne Ann Ling Hsu; Angela Takano; Adrian Chan


american thoracic society international conference | 2018

The Role of FeNO in Cough Management: A Randomised Controlled Trial

David Price; Roland Buhl; Adrian Chan; Daryl Freeman; Elizabeth Gardener; Clifford Godley; Kevin Gruffydd-Jones; Lorcan McGarvey; Ken Ohta; Dermot Ryan; Jörgen Syk; Ngiap Chuan Tan; Tze Lee Tan; Mike Thomas; Sen Yang; Priyanka Raju Konduru; Marcus Ngantcha; M. Stagno d'Alcontres; Therese S. Lapperre

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David Price

University of Aberdeen

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Dermot Ryan

University of Edinburgh

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Lorcan McGarvey

Queen's University Belfast

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Angela Takano

Singapore General Hospital

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