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Safety of Long-Acting β-Agonists
IN RESPONSE:
My coauthors and I appreciate the thoughtful comments on our meta-analysis. We would first like to clarify that our analysis included only randomized, placebo-controlled trials to assess the safety of LABAs compared with placebo. The results showed that LABA use in these trials increased asthma hospitalizations, life-threatening attacks, and asthma deaths by 2- to 4-fold compared with placebo.
In response to Dr. Ernst and colleagues' commentary elsewhere in this issue (1), we chose trials of at least 3 months' duration to allow adverse effects associated with continued treatment to develop. Long-acting β-agonists have an initial beneficial effect on asthma control that may last for a few weeks before clinically significant tolerance develops. We analyzed all events that occurred in the trials, even those that occurred in the initial few weeks, and we still found a net increased risk associated with LABA use. It is important to note that in our analysis of hospitalizations, approximately 7% of the participants were African American and all participants had full access to health care.
In response to Drs. Nelson and Dorinsky and Dr. Ernst and colleagues, our study was not designed to assess the protective effect of concomitant inhaled corticosteroids on the adverse effects of LABAs. We estimated that half of the participants in the trials were also using inhaled corticosteroids, which may approximate the degree of use in the general population when the trials were performed. A subgroup analysis of 7 trials (2–8) with more than 75% concomitant inhaled corticosteroid use (an average of 90% use) still demonstrated a 2-fold increase in asthma hospitalizations for LABA compared with placebo (odds ratio, 2.1 [95% CI, 1.3 to 3.4]). …
