Steroid inhalers commonly used to prevent asthma attacks may not work any better than a placebo for many people with mild asthma, according to recent research.

Synthetic corticosteroids mimic the steroid hormone cortisol, reducing inflammation in the airways. But the drug targets a type of inflammation that may be found in far fewer patients than previously thought, research in a recent issue of the New England Journal of Medicine finds. Among patients age 12 and older in the study who had mild, persistent asthma, more than half did just as well, or better, on a placebo as they did on a steroid inhaler.

"We're suggesting that it's time to reevaluate what the standard recommended form of treatment is for these milder patients," says Stephen Lazarus, a pulmonologist at the University of California, San Francisco, and the study's lead author.

Since the early 1990s, the international guideline for treating patients with mild, persistent asthma has been to use a low-dose steroid inhaler twice a day. The recommendation was based mainly on studies of people with severe asthma; the thinking was that if people with mild symptoms used the steroid inhaler early on, it would prevent damage to their airways later.

But when the medications didn't seem to reduce asthma attacks, doctors blamed the patients.

"For many years, I think we've attributed their poor asthma control to the fact that they weren't taking their medicines," Lazarus says, "and it may be that many of them were taking their medicines — they just weren't working."

Lazarus and his team studied around 300 patients who had mild asthma. The vast majority — 73% — did not have Type 2 inflammation, an inflammation characterized by a high level of eosinophilic white blood cells, which are believed to be much more prevalent among asthma patients.

Of those patients, 66% did just as well, or better, on a placebo as on the steroid inhaler mometasone in terms of urgent care visits, days when they had trouble breathing or nights when they woke up because they were unable to breathe.

Merck, the drug company that makes mometasone, declined to comment on the study.

"We may be giving people steroids, subjecting them to potential adverse effects and the increased costs, without a significant clinical benefit," Lazarus says.

While inhaled steroids are generally safe, there is some risk for bone loss, cataracts, glaucoma and thinning of the skin.

Bone loss has long been a concern for asthma patient Suzanne Leigh, who works in UCSF's media department.

"I'm a low-BMI white woman with a history of autoimmune disease, which puts me at high risk for osteoporosis," says Leigh.

When she read the study, Leigh says, she was frustrated to learn that the $500 asthma inhaler she uses — one that increases her risk of breaking a hip in a few years — might not even work.

"I don't know where I go from here," she says. "Do I continue with the medication, or do I stop — and end up in the emergency department?"

Lazarus suggests she follow her doctor's current recommendation. While the study suggests that guidelines on treatments for mild asthma may ultimately shift, a bigger, longer study is needed, Lazarus says, before any major clinical changes are made.

"If someone has evidence of episodic, periodic asthma and asthma exacerbations that lead to emergency department visits and they respond when treated with inhaled steroids, then it kind of doesn't matter what the lab test shows," he says. "If they have a clinical response that is genuine, that probably is an appropriate treatment regimen."

But in general, he says, there is no magic lab test that can say which asthma patients will respond to inhalers and which ones won't.

"I would say that if you have people who are taking inhaled steroids and they're not responding, the answer is not necessarily to just continue to escalate the dose," he says, "but to question whether there's an alternative."

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