Long-acting beta-agonists (LABAs), such as salmeterol, are currently the primary add-on therapy for patients with persistent asthma. However, the comparative efficacy of long-acting muscarinic antagonists (LAMAs), such as tiotropium bromide, is less clear.
To explore, researchers carried out a systematic review and meta-analysis of 15 randomised trials comparing a LAMA with placebo or a LABA, as add-on therapy to inhaled corticosteroids (ICS) in 7,122 patients with persistent asthma
The data show that LAMAs reduced the risk of exacerbations requiring systemic corticosteroids by 33% and asthma worsening by 19%, compared with placebo, but there was no significant improvement compared with LABA therapy. The researchers also discovered that triple therapy (ICS+LABA+LAMA) provided no additional benefit over ICS+LABA with regards to exacerbation risk.
Reporting in JAMA (online, 19 March 2018), the researchers said the current evidence does not suggest a significant difference between LABAs and LAMAs in preventing exacerbations but further studies are needed to determine if either is superior.
 Sobieraj D, Baker W, Nyugen E et al. Association of inhaled corticosteroids and long-acting muscarinic antagonists with asthma control in patients with uncontrolled, persistent asthma. JAMA 2018;319(14):1473–1484. doi: 10.1001/jama.2018.2757