A pilot platform for investigating novel diagnostic techniques to improve asthma diagnosis in primary care

PI Title: Dr Helen Ashdown

Lead member: University of Oxford

Asthma is a lung condition in which the airways can become narrowed and inflamed causing coughing, breathlessness and wheezing that vary over time. Currently, there is no single test to confirm whether someone has asthma, and the diagnosis is
made based on a combination of the patient’s symptoms and one or more breathing tests (e.g. spirometry) which look for airway narrowing. The problem is that, as asthma symptoms vary, the results of these tests may be normal by the time they
are done. We know from previous studies that patients find it very frustrating to have multiple tests, none of which provide a final answer, and that undiagnosed asthma can  result in long-term lung damage.

We suspect that some patients who have ‘normal’ results on currently used breathing tests may actually have lung abnormalities that make them more likely to have asthma-like symptoms – but the current tests are not sensitive (accurate)
enough to pick up these abnormalities.

Asthma is almost always diagnosed by GPs or practice nurses, but most asthma tests are developed in hospitals. We would like to start evaluating new tests for asthma in primary care settings, as this approach will give more useful information
about their accuracy and insight on how they might be used by patients and GPs/nurses.

We will recruit patients who contact their GP with symptoms suggestive of new asthma. Participants will need to be included before they start any treatments, as treatment can affect the results. Participants will have a phone call with the study GP to discuss their symptoms, followed by a study appointment, usually within a week. There, they will have all the usual tests for asthma diagnosis (spirometry, fraction of exhaled nitric oxide, FeNO), plus the new breathing tests (laser gas analysis -
sigmaCL, handheld capnometry - N-Tidal™, oscillometry - tremoflo®), as well as blood tests and questionnaires about symptoms and their experience with the different tests. They will also complete a peak flow diary at home for two weeks, using a digital Smart Peak Flow monitor via an app. We aim to recruit 100 patients with suspected asthma, plus 50 healthy volunteers with no symptoms.

The usual breathing test results from the suspected asthma group will be fed back to each participant’s GP and will be combined with symptom assessments to determine whether the patient has confirmed or unconfirmed asthma. The results will be compared between groups to see how accurate the new tests are at picking up asthma, and whether there are any abnormalities in the unconfirmed asthma group compared to healthy volunteers.