Thousands of people diagnosed with asthma don’t actually have the condition, experts warn, meaning they may be taking strong steroids unnecessarily and risk overlooking other life-threatening conditions.
To meet the criteria for an asthma diagnosis, lung capacity must be below a certain threshold, which can be measured by a device called a spirometer, which monitors how much air you can exhale. But poor access and a shortage of machines have left doctors dependent on less accurate methods.
Patients can instead 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 with similar symptoms. That is why it is important to carry out various tests. This doesn’t always happen because GPs can’t get the right one.’
The warnings follow a study published in the British Medical Journal that estimates that about a third of asthma patients could be misdiagnosed.
Misdiagnosis prevents patients from being treated for conditions they may have, including dangerously high blood pressure, coronary artery disease – when the arteries supplying 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 suffering from potentially life-threatening pulmonary hypertension
Mr Packham, pictured with his family, said the asthma treatment made his underlying condition worse
About eight million Britons have been diagnosed with asthma and about five million are receiving treatment. The condition develops when the airways that carry air in and out of the lungs become inflamed and tender, temporarily narrowing them, resulting in shortness of breath and chest tightness.
Usually this is treated with inhalers. Most patients are given a blue inhaler, which contains a medicine called sabutimol that relaxes and opens the airways. Some patients are also given preventative inhalers, which contain steroids to reduce inflammation and swelling, or an inhaler that combines both. However, these carry a risk of yeast infections in the throat and mouth and can cause a sore throat.
If inhalers fail to control asthma symptoms, patients are escalated to stronger treatments, including high-dose steroids and other medications that can cause serious side effects. With long-term use, steroids can increase the risk of osteoporosis—weak bones—and high blood pressure.
But experts say many patients who end up on the stronger drugs don’t actually have asthma. “If a patient doesn’t respond to treatment — which they generally won’t if they don’t have asthma — the dose can go up and up, increasing the likelihood of side effects,” said Andrew Bush, a professor of pediatric breathing at the National Heart Institute. and Pulmonary Institute at Imperial College London.
“The drug can stunt children’s growth and stop the body from making hormones like cortisol, which is essential for helping the brain absorb nutrients.”
Experts say misdiagnosis has been around for a long time, but the Covid pandemic has compounded the problem. This is because spirometry tests, performed in GP practices, were suspended in 2020 and 2021 because 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 have not invested in bringing back the tests for each practice because they are expensive.
“Also, some doctors are not trained in the machines, while some have the machine but don’t have the staff to operate it.”
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 mistreated for asthma was Tom Packham, 27, from Lancashire. In February, the father-of-two called his doctor complaining of shortness of breath and dizziness. 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 shortness of breath attacks.
But his symptoms got worse. Doctors offered another inhaler with stronger steroids.
Tom says, ‘First the nurse said I wasn’t using the inhaler properly, then they put me on a stronger one. I hardly saw the doctor or nurse face-to-face, which didn’t help either. I kept trying to tell them it wasn’t asthma, but they kept insisting.’
Within a few months, he became so dizzy that he had difficulty walking and fainted twice. His GP sent him for an examination, which showed that there were problems with the blood vessels that supply his lungs with blood. He was diagnosed with pulmonary hypertension – high blood pressure that 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 emphasizes that patients should not stop taking their asthma medication without consulting a GP.
“Sometimes doctors have to give drugs, even if they’re not sure about the diagnosis, to rule things out,” he says. ‘But it is crucial to review patients. If the drug doesn’t work, the diagnosis may be wrong.’