Changes in Asthma Maintenance Therapy Prescribing Patterns Following the 2006 Long-acting β-Agonist FDA Drug Warning

Purpose: The US Food and Drug Administration issued a boxed warning on all products containing a long-acting β-agonist (LABA) in March 2006, after the findings from a trial suggested an increased risk for death in patients treated with salmeterol monotherapy. Almost nothing is known about the impact of this warning on LABA prescribing patterns or on clinicians' approaches to asthma maintenance therapy.

Methods: A cohort of asthmatic adults on LABA therapy was retrospectively identified from a Baltimore-area Medicaid data warehouse. Pharmacy claims were used for determining the utilization rates of all asthma maintenance medications. Rates from the 6-month period before the warning (September 1, 2005, to February 28, 2006) were compared with rates from a similar 6-month period 1 year afterward (September 1, 2006, to February 28, 2007). The demographic characteristics of patients who continued LABA use were compared with those of discontinuers. In LABA discontinuers, utilization of alternative maintenance drugs was assessed.

Findings: In this cohort of 455 asthmatic patients, LABAs were prescribed only in combination with inhaled corticosteroids. Following the warning, 53% of patients discontinued LABA use, and the mean number of LABA prescription fills per patient decreased from 2.6 to 1.8 (P < 0.0001). Concurrently, the use of inhaled corticosteroids increased from 0.3 to 0.8 fills per patient (P < 0.0001). LABA continuers were younger (P = 0.0005), more likely to be black (P = 0.0079), and more consistent with LABA fills prewarning (P < 0.0001). Of the 243 LABA discontinuers, 155 were placed on no alternative maintenance therapy.

Implications: The management of asthma changed significantly after the LABA warning. The use of LABAs combined with inhaled corticosteroids plummeted, while the use of inhaled corticosteroid monotherapy increased. More than half of patients who discontinued LABAs were not placed on alternative maintenance therapy.