European Respiratory Society


The safety of long-acting β2-agonist (LABA) treatment in asthma has been questioned following reported increased respiratory deaths when salmeterol was added to usual pharmacotherapy. The aim of this study was to examine whether asthma, cardiac or all-cause mortality and morbidity were increased with formoterol use.

The analysis included all AstraZeneca randomised controlled parallel-group asthma trials of 3–12-months duration involving formoterol. Risks associated with formoterol use compared with non-LABA treatment, overall and in combination with inhaled corticosteroids (ICS), were assessed using an intention-to-treat analysis of the rates and rate ratios of deaths and serious adverse events (SAEs). The main objective of this study was to compare asthma-related mortality in patients using formoterol and those not using formoterol.

There were eight asthma-related deaths (0.34 per 1,000 person-yrs) among 49,906 formoterol-randomised patients (92% using ICS), and two (0.22 per 1,000 person-yrs) among 18,098 patients (83% using ICS) not randomised to formoterol, which was nonsignificant. Asthma-related SAEs (>90% of which were hospitalisations) were significantly fewer among formoterol-randomised patients (0.75 versus 1.10%). There was no increase in asthma-related SAEs with increased daily doses of formoterol (9, 18 or 36 μg). There was no significant difference in cardiac mortality or noncardiac nonasthma-related mortality in formoterol-randomised compared to non-LABA-treated patients. All-cause mortality was similar. In the data set in which all subjects were prescribed ICS at baseline, there were seven asthma-related deaths (0.32 per 1,000 person-yrs) among 46,003 formoterol-randomised patients and one (0.14 per 1,000 person-yrs) among 13,905 patients not randomised to formoterol, which was also nonsignificant.

There were few asthma-related or cardiac-related deaths among patients randomised to formoterol, and all differences were nonsignificant compared with non-long-acting β2-agonist-randomised patients. However, despite data on >68,000 patients, the power was insufficient to conclude that there was no increased mortality with formoterol. Cardiac-related serious adverse events were not increased, and asthma-related serious adverse events were significantly reduced with formoterol.


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