Long-acting anticholinergic agents in patients with uncontrolled asthma: a systematic review and meta-analysis

SETTING: A novel effective treatment is necessary for severe asthma. OBJECTIVE: To review clinical trials examining the role of tiotropium in patients with poorly controlled asthma despite inhaled corticosteroid use with or without long-acting beta(2)-agonists. DESIGN: A computerised search of electronic databases (Medline, EMBASE and Cochrane Central Register) was performed. Randomised controlled trials of at least a 4-week treatment duration with findings published in English were included. RESULTS: Five studies involving 1635 patients were analysed. Compared with a placebo or a double dose of inhaled corticosteroids, the addition of tiotropium increased mean trough and peak forced expiratory volume in 1 second by 97 ml (95%Cl 71-122) and 103 ml (95%CI 42-163), respectively. The mean differences in morning peak expiratory flow were 19.2 I/min (95%CI 11.8-26.6). Tiotropium also reduced the risk of severe acute exacerbation (OR 0.73, 95%CI 0.56-0.96) and improved Asthma Quality-of-Life Questionnaire score significantly by 0.10 (95 %Cl 0.04-0.16). There were no differences in serious adverse events. CONCLUSION: The addition of tiotropium may be beneficial for patients with poorly controlled asthma, although exacerbation or safety issues should be clarified in long-term trials before its wide use in asthma.