Asthma exacerbations during first therapy with long acting beta 2-agonists

Long acting beta(2)-agonists (LBA) have become an important therapeutic str ategy in the treatment of asthma. There is, however, debate whether LBA inc rease the risk of asthma exacerbations (AE). We studied whether the risk of AE was increased in patients starting LBA therapy and whether the risk was associated with severity. Patients, aged 5-49 years, who were firstly prescribed LBA between 1992 and 1995, and who had at least two consecutive prescriptions of LBA, were sele cted from the PHARMO-RLS database. The exposure period was the interval bet ween the first and last dispensing of the first exposure episode. The year before the onset was the control period. Single short courses of oral gluco corticosteroids or antibiotics were used as proxy indicators for AE. Severi ty indicators, assessed in the 6 months before initiation of LBA, were used to classify patients' severity. A total of 788 patients met the inclusion criteria (men: 45.1%, median age: 35). The incidence rate of AE increased significantly (p < 0.001) with sev erity from 1.7 to 2.4 and 1.1 to 2.7 AE per person year in index and contro l period, respectively. The risk was merely elevated among patients who sta rt LBA therapy without being treated with other anti-asthma drugs before (R R 1.4, 95% CI 1.0-2.2). First starters of LBA showed no overall change in incidence of AE when comp ared with the year before starting treatment. A total of 6.9% of patients u sed LBA as step-one therapy. These patients suffer, in contrast to the whol e population, a 40% increased risk of having AE. Although this could be due to confounding, we recommend being reluctant to prescribe LBA to patients who have not been treated before with other anti-asthma drugs.