The paper is a combination of two identical randomised controlled trials involving a total of 912 patients. Participants were randomly assigned to treatments with placebo or tiotropium (5 micrograms daily) via a soft mist inhaler. The study ran for 48 weeks with 456 patients receiving treatment in each group. The average age of the participants was 53 years old and approximately 76% had never smoked.
The trial demonstrated a statistically significant improvement in lung function as assessed by FEV1 with an 84ml improvement (+/-34ml; p=0.01) in trial 1 and a 154ml improvement (+/-32ml; p<0.001) in trial 2. The active treatment also increased the time to first exacerbation from 226 days to 282 days with a significant reduction in the number of severe exacerbations (hazard ratio 0.79; 95% CI 0.62-1.00; P=0.03). Side effect rates were similar and no deaths occurred during the study.
The authors conclude that, "in patients with poorly controlled asthma despite treatment with inhaled glucocorticoids and LABAs, adding tiotropium significantly reduced the risk of episodes of the worsening of asthma and asthma exacerbations requiring treatment with systemic glucocorticoids".
An accompanying editorial highlights some limitations in the study. Firstly, compliance with non-trial medication such as inhaled steroids and LABAs was not assessed. It is therefore possible that under-treatment has played a part. Secondly, this study recruited patients with persistent airflow obstruction as one of the inclusion criteria was and FEV1 to forced vital capacity (FVC) of less than 0.7. The results may not generalise to other patients without the same airflow obstruction.
Finally, it is worth noting that these trials used the soft mist inhaler and this drug and device combination has been linked with an increased risk of cardiovascular events and all-cause mortality.
Action: This trial shows early promise but tiotropium is currently unlicensed in asthma and therefore more safety and efficacy data are necessary before use in asthma can be recommended.
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