Do you have asthma? Are you sure? Draft guidance from the National Institute for Health and Care Excellence (Nice), out for consultation and not yet finalised, says that up to 30% of adults diagnosed with it “do not have clear evidence of asthma”. The percentage was the Nice committee’s best estimate, based on results from numerous studies. Nice says there is no gold standard test to diagnose asthma and that doctors mainly do it on the basis of a thorough history – asking patients about symptoms such as wheezing, coughing and breathing problems, as well as whether they have allergies or eczema.
The typical wheeze in asthma is a continuous whistling sound heard on breathing out. A family history of asthma or allergies can also increase the likelihood of having it. Nice says doctors should ask whether symptoms are worse at work, as some chemicals can trigger asthma. Asthma UK gives the number of people having treatment for asthma as 5.4 million, which would mean that, potentially, 1.6 million might be misdiagnosed. But asthma is not a trivial disease. Anyone who has had, or witnessed, an asthma attack will know how terrible it is to fight for breath. In the UK, three people a day die from asthma. So should the draft Nice guidance make you think twice about your diagnosis, or is it better to be safe than very, very sorry?
The solution
No one should hurl away their inhaler before seeing their GP. Although this guidance is about diagnosis, Nice states that, in many cases, asthma control is already inadequate, which could be life-threatening. What it is suggesting is that GPs should work through a flow chart of tests to achieve a more accurate diagnosis. Some GPs already use spirometry – a test to help diagnose various lung conditions – but Nice suggests it should be the first test for anyone over five years of age. Spirometry involves blowing into a machine that measures how much air you breathe in, and how much and how quickly you can exhale. If the results suggest that the airway is obstructed (in asthma, the muscles around the airways tighten and the lining of the airways becomes inflamed and swollen), Nice says that the next test is to see if there is improvement after use of an inhaler to widen the airways. Further tests would measure levels of nitric oxide in the breath (higher in people with asthma). Children under five should still mostly be treated on the basis of clinical judgment.
Nice says that people who already have a diagnosis of asthma and are stable should have annual reviews of their symptoms and spirometry tests. This is really important and nobody should decide they don’t have asthma before having such a review. After all, most people diagnosed with asthma do have it.
