Study challenges current treatment for mild asthma

04/11/05

People with "mild persistent asthma" -- about a quarter of all asthma sufferers -- appear to gain adequate relief by inhaling anti-inflammatory steroids only during periods of bad symptoms, rather than daily as current guidelines recommend, a new study shows.

Symptoms of mild, persistent asthma are wheezing, coughing, or chest tightness two to six days of the week, or awakening due to asthma two or three times a month. Conventional treatment usually requires two prescribed drugs: a "beta agonist" for immediate relief, and daily use of inhaled corticosteroids to reduce airway inflammation and minimize risk of severe asthma attacks and airway scarring that might permanently reduce lung capacity.

But the year-long controlled study shows that adult asthma sufferers fare about as well whether they take a steroid drug every day or only during asthma attacks. Changes in lung function, overall frequency of symptoms and the number of severe attacks were about the same, whichever regimen was followed.

According to one of the study's authors, if the estimated four million people with mild persistent asthma took inhaled steroids only when symptoms flared, the annual medication costs would be about $2 billion lower -- or up to $150 a month per patient less -- than if they took the steroids every day as current NIH guidelines recommend.

The multi-center study, known as the Improving Asthma Control Trial (IMPACT), was funded by the National Heart, Lung and Blood Institute, and led by scientists at UCSF and Harvard Medical School.

The results are being published in the April 14 issue of The New England Journal of Medicine. The issue also includes an editorial on the study and its likely impact on treatment for asthma.

"There is no question that use of inhaled corticosteroids or other anti-inflammatory drugs known as anti-leukotrienes are effective -- and necessary -- for patients with moderate or severe asthma, but our findings suggest that the NIH guidelines for treating asthma may have gone a little too far in requiring patients with truly mild asthma to take these anti-inflammatory drugs every day," said Homer Boushey, MD, professor of medicine at UCSF and study co-leader.

"This study will need confirmation before the findings should change the standard of practice, but it suggests that adults with mild asthma may do about as well if they have the medication on hand and are advised to take them for a week or two just when their symptoms flare up."

About 20 million Americans suffer from asthma, with most experiencing symptoms that are considered "mild intermittent" or "mild persistent" -- requiring occasional use of beta agonists to relieve symptoms but causing few emergency department visits or hospitalizations. Opinion has been divided among experts as to how best to treat these conditions. In 1997, an expert NIH panel recommended daily use of inhaled steroids to prevent attacks, and theoretically, to counter the possibility of permanent, debilitating airway scarring which would further aggravate breathing. But only about 30 percent of patients who are prescribed inhaled steroids refill their prescriptions.

"The steroids do not provide immediate relief; that's the job of the beta agonists such as albuterol," Boushey explained. "Either because patients experience no obvious, immediate benefit, or because they are concerned about using inhaled steroids -- or some combination of reasons -- most people discontinue steroid use for asthma. Our study shows that for mild asthma, at least for the short term, this 'folk wisdom' is a safe practice.

"We can't say for sure though that inhaled corticosteroid treatment might not be good for preventing airway 'scarring' and progressive loss of pulmonary function in the long run. What we can say is that the patients in our study, who all had mild asthma, did not have many severe attacks, and did not seem to be losing pulmonary function rapidly."

The researches noted that patients who used the corticosteroids daily did experience some benefits: "They had more symptom-free days and less bronchial inflammation. But daily use of the steroids did not significantly reduce the risk of severe attacks or prevent loss of pulmonary function," Boushey stressed.

The six-city study involved 225 adult patients with mild persistent asthma. During the one-year study, participants took daily doses of either a placebo or one of two anti-inflammatory medications -- inhalant corticosteroids or anti-leukotrienes. All participants also had use of clearly labeled inhalant steroid sprays to take for short periods for mild worsening of asthma, and prednisone tablets for more severe episodes. In this way, the study not only compared the two anti-inflammatory drugs against each other and a placebo, but also tested intermittent versus continual medication, since those in the placebo group ended up taking the anti-inflammatory mediations only during flare ups. All three groups experienced about the same degree of relief, the researchers report.

All those enrolled in the study were taught how to recognize symptoms of worsening asthma and how to treat themselves with short courses of therapy. Many patients found that simply learning how to take care of themselves made a big difference in their ability to live with their asthma after the study ended, the researchers note.

"One of the most important things we did during this study was to work closely with the participants to help them effectively manage their asthma symptoms," said Audrey Plough, RN, the nurse coordinator for the UCSF site of the study.

After one year, the three groups not only showed similar lung function and severity of symptoms, but also similar "quality of life" scores -- measures of physical, social and emotional impairments due to asthma.

"The results of IMPACT suggest that for the type of patients with mild persistent asthma included in this study, choosing not to take daily medications may be okay, but this choice should be made in consultation with the patient's healthcare provider," said Elliot Israel, MD, co-leader of the study at Brigham and Women's Hospital in Boston.

"People with more severe asthma must follow recommendations for daily medications, and all asthma patients -- even those with mild asthma -- should adequately treat their symptoms," he added.

The National Asthma Education and Prevention Program which had recommended the daily anti-inflammatory regimen for patients with mild, persistent asthma, is expected to consider the results of the new IMPACT study and others in developing updated guidelines for treatment next year, the researchers note.

"The results of IMPACT will have tangible benefits for both asthma patients and providers," said James Kiley, PhD, director of the NHLBI Division of Lung Diseases. "We established the Asthma Clinical Research Network several years ago for just this purpose -- to generate meaningful data on new therapeutic approaches."

Participating centers in the trial, in addition to UCSF and Harvard, were: Columbia Presbyterian Medical Center and Harlem Lung Center, New York; National Jewish Medical and Research Center, Denver; University of Wisconsin, Madison; and Thomas Jefferson Medical College, Philadelphia, PA.

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Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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