Thousands of people diagnosed with asthma don’t actually have the condition, experts have warned, meaning they could be taking potent steroids unnecessarily and risk having other life-threatening conditions missed.
To meet the criteria for an asthma diagnosis, lung capacity must be below a set threshold, which can be measured by a device called a spirometer that monitors how much air you can exhale. But poor access and short supplies of the machines have left doctors reliant on less accurate methods.
Patients instead may be diagnosed based on symptoms and the results of a so-called peak flow test, a much more basic measure of lung capacity.
Dr Azeem Majeed, professor of primary care and public health at Imperial College London, says: ‘Asthma can be difficult to diagnose because there are many other conditions that feature similar symptoms. That’s why it is important to carry out a range of tests. This isn’t always happening because GPs can’t get the right ones.’
The warnings follow a study, published in the British Medical Journal that estimates roughly a third of asthma patients could be wrongly diagnosed.
Misdiagnosis prevents patients receiving treatment for conditions they may have, which could include dangerously high blood pressure, coronary heart disease – when the arteries that supply the heart are narrow – and chronic obstructive pulmonary disease (COPD), when the lungs are inflamed and damaged.
Father of two Tom Packham, 27, from Lancashire was wrongly diagnosed with asthma when he was suffering from potentially life-threatening pulmonary hypertension
Mr Packham, pictured with his family, said the asthma treatment made his underlying condition worse
Roughly eight million Britons have been diagnosed with asthma and about five million receive treatment. The condition develops when the airways that carry air in and out of the lungs become inflamed and sensitive, which causes them to temporarily narrow, resulting in breathlessness and a tight feeling in the chest.
Usually this is treated with inhalers. Most patients will be given a blue inhaler, which contains a medication called sabutimol that relaxes and opens up the airways. Some patients are also given preventer inhalers, which contain steroid medicine to keep down inflammation and swelling, or an inhaler that combines the two. However, these carry a risk of fungal infections in the throat and mouth and can cause sore throats.
If inhalers aren’t controlling the asthma symptoms, patients are escalated to stronger treatments, including high-dose steroids and other medicines that can cause serious side effects. When taken for long periods, steroids can increase the risk of osteoporosis – weak bones – and high blood pressure.
But experts say many patients who end up on the stronger medications don’t in fact have asthma. ‘If a patient isn’t responding to treatment – which they generally won’t if they don’t have asthma – the dose can keep getting increased, making side effects more likely,’ says Andrew Bush, professor of paediatric respirology at the National Heart and Lung Institute at Imperial College London.
‘The medication can stunt growth in children and stop the body making hormones such as cortisol, which is essential in helping the brain absorb nutrients.’
Experts say misdiagnosis has long existed, but the Covid pandemic amplified the problem. This is because spirometry tests, performed in GP surgeries, were paused during 2020 and 2021 as they were considered high-risk.
In some areas, testing capacity is still not back to pre-pandemic levels, says Prof Majeed. ‘They are funded by local health chiefs, not individual GP services,’ he adds. ‘Some local teams haven’t invested in bringing the tests back for every practice, as they are expensive.
‘Also, some doctors aren’t trained on the machines while some may have the machine but lack the staff to operate them.’
This means doctors diagnose asthma based on symptoms and the results of a peak flow test – but the result can change if a patient has exercised or is stressed or tired.
One patient wrongly treated for asthma was Tom Packham, 27, from Lancashire. In February, the father-of-two called his GP complaining of breathlessness and feeling dizzy. He was told to monitor his lung function at home with a peak flow device and the results were used to diagnose asthma. He was given a preventer inhaler and a blue inhaler for attacks of breathlessness.
But his symptoms got worse. Doctors offered another inhaler containing stronger steroids.
Tom says: ‘First, the nurse said I wasn’t using the inhaler right, then they put me on a stronger one. I hardly saw the GP or nurse face-to-face, which didn’t help. I kept trying to tell them it wasn’t asthma but they kept insisting.’
Within a few months he became so dizzy he struggled to walk, and passed out on two occasions. His GP sent him for tests, which showed problems with the blood vessels supplying his lungs. He was diagnosed with pulmonary hypertension – high blood pressure which can lead to heart failure.
Tom is on medication for his condition and can now walk relatively comfortably, but he still doesn’t know what the future holds. ‘I try to stay positive,’ he says.
Prof Majeed stresses patients should not stop taking their asthma medication without talking to a GP.
‘Sometimes doctors have to give medicine even if they’re not certain of the diagnosis, to rule things out,’ he says. ‘But it is crucial to review patients. If the medicine isn’t working, it is possible the diagnosis isn’t right.’