Rationale: Studies evaluating the safety of salmeterol are inconclusive, which might be the result from not taking into account the impact of concomitant inhaled corticosteroids (ICS).
Objective: To study whether salmeterol use with and without concomitant ICS, respectively, was associated with an increased risk of asthma-related hospitalizations among patients with asthma.
Methods: A case-control study nested within a cohort of patients with asthma, identified in the year 2000, over a 2-year period was conducted. Cases were subjects who had a first-time hospitalization for asthma in the year 2001, and were matched with up to five controls by age (+/- 5 years), sex, and number of asthma-related outpatient visits.
Measurements: Hospitalizations and medication use were extracted from the MEDSTAT's MarketScan database.
Main results: There were 333 cases of asthma-related hospitalizations and 1607 matched control subjects. Any use of salmeterol with concomitant ICS use during the prior year was associated with a 32% risk reduction for being hospitalized due to asthma (OR = 0.68; 95% CI = 0.48, 0.96). In the presence of concomitant ICS use, patients who either used salmeterol currently or used seven or more canisters of salmeterol during the prior year had 46% (OR = 0.54, 95% CI = 0.32, 0.92), and 59% (OR = 0.41, 95% CI = 0.21, 0.79) reductions in the risk of hospital admissions for asthma, respectively.
Limitations: Though indirect measure of asthma severity was adjusted during the analyses, the lack of information on lung function might result in a selection bias. Additionally, only a small sample size of patients was found to use salmeterol without concomitant ICS use, and this introduced the issue of lack of power.
Conclusions: Use of salmeterol in conjunction with ICS is associated with a decreased risk of hospital admission for asthma.