CompletedNot Applicable

Diagnostic and Translational Values of Point-of-care Blood Eosinophils and Exhaled Nitric Oxide (FeNO) in People Referred by Primary Care for Suspected Asthma

Canada123 participantsStarted 2022-11-07

Plain-language summary

Asthma is characterised by episodic symptoms (attacks) caused by airway inflammation and decreased airflow to the lungs. It affects 10% of the Canadian population and is the most common chronic disease in childhood. Despite its burden and its potential to be life-threatening, establishing the diagnosis takes time due to difficulty in accessing specialised breathing tests. Indeed, the current diagnostic strategy relies on a breathing test (spirometry) and, if non-diagnostic, a subsequent more complicated breathing test conducted in hospitals (a bronchial provocation test). Our dependence on the latter test must be confronted to the bottleneck created by our reliance on it and the difficulty to do these tests in children. Furthermore, within the current framework, people receiving a diagnosis do not know if they have active airway inflammation - a key feature with predicts increased susceptibility to asthma attacks and treatment responsiveness. Our study's goal is to validate clinically accessible and useful diagnostic tests for peoplesuspected to have asthma. Specifically, we are interested in alternative tests that are a) achievable outside the hospital; b) useful markers of airway inflammation/risk c) can identify people at with a higher likelihood of responding to anti-inflammatory therapy. The two tests we are mainly interested in are: * Exhaled nitric oxide (measured with a portable handheld machine) * The blood eosinophil count (obtained on a general blood test) +/- Other tests which we might be able to develop within this cohort (e.g. urine tests)

Who can participate

Age range18 Years

SexALL

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Inclusion Criteria: * aged ≥ 12 years who have symptoms suggestive of asthma, * referred by their primary care provider (defined as a non-respirologist, non-allergist, non-otolaryngologist) using the CHUS suspected asthma decision-making algorithm. Under that algorithm, patients have non-diagnostic pre- and post-bronchodilator spirometry and no contraindications to a methacholine challenge. * Free and informed consent must be given by the patient (and their legal guardian, if applicable). Exclusion Criteria: * Use of an inhaled or systemic corticosteroid in the previous 48 hours; * Smoking in the previous 6 hours; history of viral and/or bacterial respiratory infection in the past 4 weeks; * major cardiopulmonary disease, including: a) chronic obstructive pulmonary disease (COPD), defined by all of the following: i) aged ≥ 40 years , ii) permanent obstruction on spirometry (FEV1/FVC \<0.7) and iii) a smoking history of \>10 pack-years or known alpha-1-antitrypsin deficiency, b) lung conditions deemed significant by the investigator, including cystic fibrosis and bronchiectasis, and c) unstable heart disease.

What they're measuring

AUC of the ROC analysis to diagnose asthma

Timeframe: FeNO measured on the day of the methacholine challenge (i.e. Baseline visit)

Blood eosinophil count: ROC analysis AUC to diagnose asthma

Timeframe: Blood eosinophils measured on the day of the methacholine challenge (i.e. Baseline visit)

Combination of FeNO + Blood eosinophil count: ROC analysis AUC to diagnose asthma

Timeframe: FeNO and blood eosinophils measured on the day of the methacholine challenge (i.e. Baseline visit)

Trial details

NCT IDNCT05992519

SponsorUniversité de Sherbrooke

Sponsor typeOTHER

Study typeOBSERVATIONAL

Primary completion2025-10-30

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