TUESDAY, May 21, 2019 (HealthDay News) -- A widely used type of asthma medication may not work in more than half of patients who are prescribed it, new research shows.
Inhaled corticosteroids, which are designed to reduce airway inflammation, are recommended for all patients with persistent asthma.
But this medication's effectiveness may be limited to a type of inflammation that occurs in far fewer patients than once thought, according to the researchers.
For the study, which was funded by the U.S. National Heart, Lung, and Blood Institute, investigators compared the use of an inhaled steroid called mometasone (Nasonex) to a placebo in 295 patients over 12 years of age with mild persistent asthma.
The patients were grouped according to the level of eosinophils (Eos), a type of white blood cell, in their phlegm. In all, 73% were "Eos low" -- about 50% more than the researchers expected. The remaining 27% were "Eos high."
Among those who were Eos low, there was no significant difference in response to mometasone versus the placebo. And about 66% did as well or better on the placebo, the findings showed.
Eos-high patients were nearly three times more likely to respond to the inhaled steroid than to the placebo (74% versus 26%), according to the study published May 19 in the New England Journal of Medicine.
One lung expert noted inhaled steroids have been used to treat asthma for decades.
"Aerosolized steroids revolutionized the treatment of asthma in the 1990s, and so it is curious to come upon a study wherein more than half of asthmatics studied responded to aerosolized steroid no better than placebo," said Dr. Len Horovitz, a pulmonary specialist with Lenox Hill Hospital in New York City. But he noted that accurately measuring Eos levels in the phlegm can be difficult.
The researchers also looked at use of a medication called tiotropium (Spiriva), which is prescribed along with inhaled steroids. Tiotropium relaxes the muscles that tighten around the airways in asthma.
Though there was not enough evidence to conclude that patients prescribed tiotropium are likely to do better, the results suggested that alternatives to inhaled steroids should be studied further, the researchers said.
"The take-home message is that many patients have a pattern of inflammation that makes them less likely to respond to inhaled steroids," explained study first author Dr. Stephen Lazarus. He's a professor in the division of pulmonary and critical care medicine at the University of California, San Francisco.
"Doctors should consider this if patients are not responding, rather than just increasing the dose," he suggested in a university news release.
The U.S. Centers for Disease Control and Prevention has more on asthma.
SOURCE: Len Horovitz, M.D., pulmonary specialist, Lenox Hill Hospital, New York City; University of California, San Francisco, news release, May 19, 2019