Increasing asthma inhaler strength does not prevent serious attacks and may stunt growth, study finds

An extra-strong dose of asthma medication given to children to help control their condition does nothing to prevent serious attacks and could even stunt their growth, experts have warned.

Scientists found that children moved to a higher dose of their steroid inhaler when their symptoms showed they were likely to suffer a serious exacerbation of their condition, suffered no fewer attacks than children who kept their regular dose.

More worryingly, these children were shown to have grown more slowly than those whose dose was not increased, growing 0.23cm per year less on average, and were exposed to more harmful steroids.

“Low-dose inhaled steroids remain the cornerstone of daily treatment in affected children,” said study lead Dr Daniel Jackson, associate professor of paediatrics at the University of Wisconsin School of Medicine and Public Health.

“But these findings suggest that a short-term increase, to high-dose inhaled steroids, should not be routinely included in asthma treatment plans for children with mild-moderate asthma who are regularly using low-dose inhaled corticosteroids.”

Temporary high-dose steroids are recommended by Global Asthma Initiative guidance, and are used by doctors in the UK and US, particularly for school age children who might not have strategies for controlling their asthma without medication.

More than 5 million people in the UK suffer from asthma and uncontrolled attacks can to long-term lung damage, or even death.

Worsening asthma symptoms can signal a serious exacerbation could be coming, and while higher steroid exposure can have long-term effects it is thought to be worth it to prevent a serious attack.

These can be brought on by respiratory infections, like a cold or flu, hay fever or air pollution.

“Exacerbations are frequently heralded by slowly declining lung function and increasing asthma symptoms,” said Dr Philip Bardin, of the Monash University and Medical Centre in Melbourne, Australia, in an editorial reviewing the study published in the New England Journal of Medicine (NEJM) today.

“These acute flares of asthma are detrimental because they adversely affect quality of life, lung function and healthcare costs, and have the potential to end in death.”

This was true in the case of five-year-old Ellie-May Clark who died after she was turned away by her GP for being 10 minutes late to an emergency appointment, but had originally left school wheezing and in pain.

“Asthma specialists have long thought that this condition, termed the “yellow zone”, provides the perfect timing for initiating more aggressive care,” Dr Bardin added.

For the study, conducted at multiple hospitals across the US, 254 children with mild to moderate asthma, aged five to 11, were recruited for a 48-week trial.

All the children were using regular steroid inhalers called glucocorticoids twice daily to control their asthma.

They were randomly assigned to two groups, one which would continue with their conventional dose of inhaled steroids when they were showing “yellow zone” exacerbation signs.

The other group were given a dose that was five times stronger, which they would maintain for a week when symptoms worsened, with neither patients or doctors knowing what treatment they were getting.

The study found that high-dose treatment did not reduce asthma exacerbations, delay the onset of these exacerbations or improve symptoms.

It also exposed young patients to higher doses of powerful corticosteroids which increase their risk of osteoporosis, high blood pressure, eye disorders and diabetes later in life.

“The association with slower growth in height ... observed in the high-dose group was unexpected,” study authors said.

Even though the difference between the heights of the two groups was small, children in the high-dose group only had just over two weeks on the high-dose treatment.

The authors said longer-term use could have a bigger impact, adding: “This relationship arouses the concern that more frequent or prolonged use of this strategy, if the use of inhaled glucocorticoids was its cause, could lead to greater adverse effects.”

“This study allows caregivers to make informed decisions about how to treat their young patients with asthma,” said Dr James Kiley, director of the lung diseases division of the US National Heart, Lung and Blood Institute – which funded this research.

“Trials like this can be used in the development of treatment guidelines for children with asthma.”