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Study Faults Data on Asthma Inhalers and Growth

Researchers say it didn't take compliance into account

WEDNESDAY, Oct. 9, 2002 (HealthDayNews) -- Several recent studies have reassured the parents of asthmatic children that their youngsters' growth will not be stunted by the use of inhaled steroids.

However, researchers in the United States and Denmark are wondering out loud how reassuring those studies should be. They question whether the results were truly definitive because they didn't account for compliance rates. The latest round in this volley appears as a research letter in tomorrow's issue of The New England Journal of Medicine.

In medicine, compliance is a measure of how often a patient takes a prescribed medication. If the prescription is to take two puffs of an inhaler twice a day, and a child only takes two puffs in the morning, he is only 50 percent compliant.

"Past research which did not include measures of compliance should be interpreted with caution," says one of the authors, Dr. Ole Wolthers from the Children's Clinic in Randers, Denmark.

Almost 5 million American children have asthma, according to the American Academy of Allergy, Asthma and Immunology. Asthma is responsible for 5,000 deaths in the United States every year and accounts for almost 2 million hospital visits annually. Each year, 14 million school days are missed because of asthma.

Inhaled steroids are one of the most effective preventive treatments available to control asthma. They help to reduce the underlying inflammation that makes it difficult to breathe. However, Wolthers says that few patients on these medications stay compliant over the long term.

In the letter, Wolthers and his co-author, Dr. David Allen from the University of Wisconsin Children's Hospital, cite a study on compliance that monitored the actual use of medications by implanting an electronic chip into the inhaler to record dosing information. That study found compliance was near 80 percent at three months, but dropped to 54 percent at nine months and fell even further, to 49 percent, at 27 months of use.

Since previous studies have found that growth rates are slowed during the first year of inhaled steroid use and then gradually level off back to normal, the authors theorize that in the beginning, when compliance is at its highest, children are receiving a high enough dose to affect their growth. Later, as compliance wanes, the dose they receive is not sufficient to alter their growth rate, suggest Wolthers and Allen.

Does this mean parents should take their children off inhaled corticosteroids? Absolutely not.

"Steroids are important drugs in asthma management," confirms Wolthers. "They maintain lung function in the long term and in many cases may be lifesaving."

What the authors do recommend is that future studies take into account the likely lack of compliance.

Dr. Susanna McColley, acting head of the division of pulmonary medicine at Children's Memorial Hospital in Chicago, agrees that compliance should be considered in studies of the long-term effects of inhaled corticosteroids, but says that parents shouldn't be unduly alarmed by this issue. First, she points out that the data from the studies reflect real-life usage of the medications. She adds that, even in the worst-case scenario, growth might only be affected by a centimeter or two.

"Clearly, inhaled corticosteroids save lives and improve children's ability to attend school and avoid illness," says McColley. "Don't toss out a very effective medication for a theoretical concern."

She does, however, recommend that children be on the lowest dose of steroid possible. She also says that if your child's asthma is stable -- no missed school, no coughing at night, and no visits to the emergency room -- you should talk a doctor about reducing the dose of inhaled steroids. Also, children who are on inhaled steroids long-term should be visiting their doctors periodically and they should have their growth monitored, McColley adds.

What To Do

For more information about asthma, go to Kid's Health. To learn more about asthma medications, including inhaled steroids, visit the American Academy of Allergy Asthma and Immunology.

SOURCES: Ole Wolthers, M.D., Children's Clinic, Randers, Denmark; Susanna McColley, M.D., acting head, division of pulmonary medicine, Children's Memorial Hospital, and associate professor, pediatrics, Feinberg School of Medicine, Northwestern University, Chicago; Oct. 10, 2002, The New England Journal of Medicine
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