First-Line Diagnostic Investigations for Suspected Adult Asthma

NCT07792213 | Active Not Recruiting

• 1 other identifier: 2215_1715
• Study Type: observational
• Target: 2,176
• Locations: 1 country
• Sites: 1

Brief Summary

Asthma is a common long-term condition that can be difficult to diagnose accurately. Symptoms such as breathlessness, wheeze and cough can vary over time and may be caused by other conditions. Some people with asthma have normal breathing test results when they are assessed, which can make diagnosis challenging and lead to delays in treatment. This study aims to determine which commonly used tests, either alone or in combination, are most accurate for diagnosing asthma in adults with suspected disease. Participants referred to George Eliot Hospital for investigation of possible asthma will be invited to take part. Following informed consent, participants will undergo a range of routine diagnostic tests during their first visit. These include spirometry with bronchodilator response testing in patient with both normal airway function and airflow obstruction, fractional exhaled nitric oxide (FeNO), which measures airway inflammation, and oscillometry, which assesses how air moves through the lungs. Participants will then attend a second visit for a bronchial provocation challange test, which helps determine whether the airways are unusually sensitive, a key feature of asthma. The study will compare the results of these tests with the final diagnosis to assess how accurately each test identifies or excludes asthma. It will also investigate whether combining different tests improves diagnostic accuracy and whether factors such as obesity affect diagnostic measurements of increased asthma prevalence. The findings will help improve understanding of the most effective ways to diagnose asthma in routine clinical practice. This may lead to faster and more accurate diagnoses, reduce the need for unnecessary investigations, and support better care for people with suspected asthma.

Conditions

Asthma (Diagnosis)

Outcome Measures

Primary Outcomes (1)

• Primary outcome measure- Sensitivity, Specificity, Positive Predictive Value, Negative Predictive Value, and Area Under the ROC Curve of Combined First-Line Objective Testing for Asthma Diagnosis

  Diagnostic performance of combined first-line objective investigations (fractional exhaled nitric oxide \[FeNO\], oscillometry, spirometry, and bronchodilator reversibility testing) compared with the composite reference standard incorporating bronchial provocation testing. Diagnostic performance will be assessed using sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating characteristic curve (AUC).

  6 weeks

Secondary Outcomes (4)

• Secondary out come measure - Number and Proportion of Participants Requiring Bronchial Provocation Testing Following First-Line Assessment

  6 weeks

• Diagnostic Concordance Between First-Line Objective Investigations and the Composite Reference Standard

  6 weeks

• Diagnostic Performance of First-Line Objective Investigations According to Obesity Status

  6 weeks

• Diagnostic Performance of First-Line Objective Investigations in Participants With Preserved Baseline Spirometry

  6 weeks

Interventions

Spirometry DIAGNOSTIC_TEST

Participants will undergo standardised pre-bronchodilator spirometry using a calibrated spirometer operated by trained study personnel. Measurements will include forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), slow vital capacity (SVC), peak expiratory flow (PEF) and the FEV₁/FVC ratio. Participants will perform at least three acceptable forced expiratory manoeuvres, with the highest reproducible values recorded. Spirometry will be conducted at the protocol-specified study visit(s) to assess pulmonary function as an outcome measure. Testing will follow current international quality control and acceptability standards.

Fractional Exhaled Nitric Oxide DIAGNOSTIC_TEST

Participants will undergo FeNO measurement using a calibrated nitric oxide analyser operated by trained study personnel. The test will be performed according to standardised international guidelines using a controlled exhalation at a constant flow rate. FeNO values, expressed in parts per billion (ppb), will be recorded to assess airway inflammation. Measurements will be obtained at protocol-specified study visit(s) under standardised testing conditions, with quality control procedures followed throughout testing.

bronchodilator response DIAGNOSTIC_TEST

Participants will undergo bronchodilator response testing to assess for airway responsiveness in both obstructive and normal patients. Spirometry will be performed before and after administration of a standardised dose of an inhaled short-acting bronchodilator delivered via a metered-dose inhaler with a spacer. Post-bronchodilator spirometry will be conducted after the protocol-specified waiting period. Changes in forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), and other spirometric parameters will be recorded according to standardised international guidelines. Testing will be performed by trained study personnel using calibrated equipment.

oscillometry DIAGNOSTIC_TEST

Participants will undergo respiratory oscillometry using a calibrated oscillometry device operated by trained study personnel. Measurements will be obtained during quiet tidal breathing according to standardised international guidelines. Respiratory impedance parameters, including airway resistance (e.g., R5, R20), reactance (e.g., X5), resonant frequency (Fres), and area of reactance (AX), will be recorded. At least three acceptable measurements meeting quality control criteria will be obtained. Testing will be performed at protocol-specified study visit(s) under standardised conditions to assess respiratory mechanics.

Bronchial Provocation challange test DIAGNOSTIC_TEST

Participants will undergo a standardised bronchial provocation challenge to assess airway hyperresponsiveness. Increasing doses of a bronchial provoking agent will be administered according to a standardised protocol under the supervision of trained study personnel. Spirometry will be performed after each dose to measure changes in forced expiratory volume in one second (FEV₁). The test will continue until a predefined decline in FEV₁ is achieved or the maximum protocol dose is reached. Testing will be performed using calibrated equipment with continuous monitoring and appropriate safety procedures, following current international guidelines.

Eligibility Criteria

• Age: 16 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)
• Sampling Method: Probability Sample

Study Population

Potential participants will be identified from adults referred to the Physiological Sciences Department at George Eliot Hospital NHS Trust for objective investigation of suspected asthma through routine primary or secondary care referral pathways. Eligible participants will be assessed by the research team. Only patients who provide written informed consent will be enrolled into the study. Following consent, the lead researcher will access relevant electronic healthcare records to collect the clinical information required for the study, as described in the consent form. Study data will be assigned a unique pseudonymised study identification number and stored securely, password-protected, on the Trust's systems. Access to identifiable information will be restricted to authorised members of the research team in accordance with the UK GDPR, the Data Protection Act 2018 and NHS information governance policies.

You may qualify if:

• Adults aged 16years and older
• Referral for objective investigation of suspected asthma
• Ability to provide written informed consent

You may not qualify if:

• Previous confirmed diagnosis of asthma or other chronic airways disease
• Respiratory tract infection within six weeks prior to testing
• Current smoker or ex-smoker with a greater than 10p\\pack-year smoking history
• Inability to perform pulmonary function testing to acceptable technical standards
• Contraindications to any of the diagnostic investigations as per departmental guidelines
• Lack of capacity to provide informed consent

Sponsors & Collaborators

• George Eliot Hospital: lead

Study Sites (1)

Physiological Sciences

Nuneaton, North Warwickshire, CV10 7DJ, United Kingdom

Location

MeSH Terms

Conditions

Asthma; Disease

Interventions

Spirometry; Fractional Exhaled Nitric Oxide Testing

Condition Hierarchy (Ancestors)

Bronchial Diseases; Respiratory Tract Diseases; Lung Diseases, Obstructive; Lung Diseases; Respiratory Hypersensitivity; Hypersensitivity, Immediate; Hypersensitivity; Immune System Diseases; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Respiratory Function Tests; Diagnostic Techniques, Respiratory System; Diagnostic Techniques and Procedures; Diagnosis; Breath Tests

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 7, 2026
• First Posted: August 28, 2026
• Study Start: August 2, 2026
• Primary Completion (Estimated): February 27, 2028
• Study Completion (Estimated): July 30, 2028
• Last Updated: August 28, 2026

Record last verified: 2026-08

Locations

GB (1)