WASHINGTON — Children with asthma who used 6 or more canisters of short-acting beta2-agonists in a year had twice the risk of asthma exacerbation, compared with children who used fewer than 6 canisters, based on results of a database review of more than 33,000 children aged 6-17 years.
Studies have shown an association between increased use of short-acting beta2-agonists (SABAs) and asthma exacerbation in children, but a threshold for high SABA use has not been established, said Christopher M. Blanchette, Ph.D., of Lovelace Respiratory Research Institute in Kannapolis, N.C.
Dr. Blanchette and his colleagues reviewed data from 33,951 children with asthma who were continuously enrolled for 2 years in the PharMetrics Patient-Centric Database (a pool of more than 70 commercial health insurance plans) between July 1, 2003, and June 30, 2007. The researchers excluded children with chronic obstructive pulmonary disease, bronchitis, cystic fibrosis, and other conditions that required oral cortico-steroids. Average age was 11 years.
Asthma exacerbation was determined by any or all of the following: oral corticosteroid prescriptions, urgent care or emergency department visits for asthma, and hospitalizations for asthma.
Overall, most (70%) children used 0-2 canisters per year. A total of 24% of the children used no canisters, 46% used 0.5-2 canisters, 23% used 2.5-6 canisters, 5% used 6.5-12 canisters, and 2% used more than 12 canisters, according to the results presented at annual meeting of the American Academy of Allergy, Asthma, and Immunology.
A total of 3,147 children (9%) used 6 or more SABA canisters, which was significantly associated with asthma exacerbation. In addition to a doubled risk of asthma exacerbation, children who used 6 or more canisters per year were more than three times as likely to be hospitalized or to have emergency department or urgent care visits, compared with children who used 0-5 canisters.
The study was limited by a lack of control for all potentially confounding factors, including the use of inhaled corticosteroids, the researchers wrote. The most common comorbidities were allergies or allergic rhinitis (35%), acute pharyngitis (25%), and acute upper respiratory infections (22%).
Although most of the children in the study did not meet the threshold associated with increased risk, the findings highlight the need for physicians to watch for the overuse of SABAs as a sign of uncontrolled asthma and adjust treatment accordingly to reduce the risk of exacerbation. The study was sponsored by AstraZeneca PLC.
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