CAMP is the longest and largest controlled study of treatments for childhood asthma to date. It showed that inhaled corticosteroids provide superior asthma control. Their only side effect was a temporary one -- a small reduction in the children's rate of growth observed just in the first year of treatment. The inhaled corticosteroids significantly reduced airway hyperresponsiveness, the heightened sensitivity in the airways that leads to asthma symptoms following exposure to certain irritants and allergens. However, their use did not result in the anticipated improvements in measures of lung function.
"Although asthma experts around the world have recognized the effectiveness of inhaled corticosteroids in treating asthma, their long term effects in children were not clear, and questions have been raised about their possible effects on growth," said NHLBI Director Dr. Claude Lenfant. "CAMP confirms their effectiveness while providing reassuring evidence about their safety."
"We hope these results will convince more physicians, and parents as well, that treating children with mild to moderate asthma with inhaled corticosteroids will result in better asthma control and improved quality of life, " he added.
Asthma is the most common chronic respiratory disease of childhood throughout the world, and its prevalence has been increasing in epidemic proportions worldwide. In the U.S., asthma affects close to 5 million children, approximately 30-40 percent of whom are estimated to have mild to moderate asthma (symptoms more than twice a week). Childhood asthma is a leading cause of school absences – resulting in more than 11 million lost school days a year. It is currently estimated to cost the U.S. economy nearly $2 billion each year.
CAMP involved more than 1,000 children ages 5-12 with mild to moderate asthma. The children were randomly assigned to receive either budesonide, an inhaled corticosteroid; nedocromil, a non-steroid anti-inflammatory medication; or a placebo. All children were also provided with a beta-agonist for use, as needed, to relieve symptoms.
CAMP showed that the inhaled corticosteroid provided superior asthma control. Compared to children on placebo, children treated with the steroid had 45 percent fewer urgent care visits; 43 percent fewer hospitalizations; 45 percent less use of oral steroids, which are used to treat severe exacerbations; 30 percent fewer days in which additional asthma medication was needed; and 22 percent more episode-free days. The nedocromil group had 27 percent fewer urgent care visits and 16 percent less use of oral steroids, compared to the group on placebo, but there was no difference between the nedocromil and placebo groups in hospitalizations, use of additional medications, or episode-free days.
The only side effect from the inhaled corticosteroids was a slight, but temporary, reduction in growth rate. In the first year of the study, the average increase in height in the children treated with budesonide was about 3/8 of an inch less than that of the other children. However, after the first year and throughout the remaining 4 years of the study, the children on budesonide grew at the identical rate as the other children. Wrist x-rays taken at the end of the study suggest that the adult height of these children will be the same as that of the children taking nedocromil or placebo. (A second study in the October 12, 2000 NEJM, which followed children with asthma into adulthood, found that the children with asthma who received long-term treatment with budesonide attained normal adult height.)
Said Lenfant, "We recognize that even a slight slowing of growth may be a concern for parents. But this effect was short term and temporary – after the first year, the growth rates were the same in all groups. And there are substantial long-term benefits of enabling a child with asthma to be active at play and school, to sleep through the night and to stay away from the emergency department and hospital."
"We will continue to observe CAMP participants for another 4 years, by which time most of them will have reached puberty. This will give us a complete picture of the effects of inhaled corticosteroids on both final adult height and maximum adult lung function," he added.
Several recent smaller studies have suggested that childhood asthma may be associated with impairments in lung growth and a steady decline in lung function. The CAMP investigators hypothesized that treating children with asthma with anti-inflammatory medication might improve lung growth and reduce lung function decline. However, at the end of the study, there were no differences in lung function in any of the groups, when measured after administration of a bronchodilator to relax the airways. It is possible that the children had already experienced an irreversible decline in lung function by the time they enrolled in CAMP, and treatment was not started early enough to effect change. Future NHLBI studies will examine asthma treatments in younger children.
The NHLBI's 1991 "Guidelines for the Diagnosis and Management of Asthma," with their emphasis on inflammation, rather than bronchospasm, as the underlying cause of asthma, marked the beginning of a new approach to treating asthma. The Guidelines recommended anti-inflammatory medications for long-term asthma control in people with frequent asthma symptoms, although data on their long term effects in children were limited. Since the CAMP study started, new asthma medication have become available, including long-acting beta agonists and leukotriene modifiers, but data on their long-term effects in children are not yet available.
Said Lenfant, " CAMP provides scientific evidence regarding the long term effectiveness and safety of inhaled corticosteroids for children. Physicians, other health care professionals, and parents should feel comfortable using them to help children with mild to moderate asthma participate fully in childhood activities."
Participating CAMP clinical centers are: Asthma, Inc., Seattle, WA; Brigham and Women's Hospital, Boston, MA; Hospital for Sick Children, Toronto, Ont.; Johns Hopkins Asthma and Allergy Center, Baltimore, MD; National Jewish Medical and Research Center, Denver, CO; University of California and Kaiser Permanente Southern California Region; University of New Mexico, Albuquerque, NM; and Washington University, St. Louis, MO. The CAMP data coordinating center is Johns Hopkins University.
The medications used in CAMP were donated by AstraZeneca, Wayne, PA; Aventis, Parsippany, NJ; Glaxo Research Institute, Research Triangle Park, NC; and Schering-Plough, Kenilworth, NJ.
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