Tiotropium versus placebo for inadequately controlled asthma: a meta-analysis

Objective: This meta-analysis was performed to evaluate the efficacy and safety of the addition of tiotropium to standard treatment regimens for inadequately controlled asthma.

Methods: A systematic search was made of PubMed, EMBASE, MEDLINE, and CENTRAL databases, and ClinicalTrials.gov, and a hand search of leading respiratory journals. Randomized, double-blind clinical trials on the treatment of inadequately controlled asthma for ≥ 4 weeks with the addition of tiotropium, compared with placebo, were reviewed. Studies were pooled to odds ratio (OR) and weighted mean differences (WMDs), with 95% CI.

Results: Six trials met the inclusion criteria. The addition of tiotropium, compared with placebo, significantly improved all spirometric indices, including morning and evening peak expiratory flow (WMD 20.59 L/min, 95% CI 15.36-25.81 L/min, P < .001; and WMD 24.95 L/min, 95% CI 19.22-30.69 L/min, P < .001, respectively), trough and peak FEV1 (WMD 0.13 L, 95% CI 0.09-0.18 L, P < .001; and WMD 0.10 L, 95% CI 0.06-0.14 L, P < .001, respectively), the area under the curve of the first 3 h of FEV1 (WMD 0.13 L, 95% CI 0.08-0.18 L, P < .001), trough and peak FVC (WMD 0.1 L, 95% CI 0.05-0.15 L, P < .001; and WMD 0.08 L, 95% CI 0.04-0.13 L, P < .001, respectively), the area under the curve of the first 3 h of FVC (WMD 0.11 L, 95% CI 0.06-0.15 L, P < .001). The mean change in the 7-point Asthma Control Questionnaire score (WMD -0.12, 95% CI -0.21 to -0.03, P = .01) was markedly lower in tiotropium group, but not clinically important. There were no significant differences in Asthma Quality of Life Questionnaire score (WMD 0.09, 95% CI -0.01 to 0.20, P = .09), night awakenings (WMD 0.00, 95% CI -0.05 to 0.05, P = .99) or rescue medication use (WMD -0.18, 95% CI -0.36 to 0.00, P = .06). No significant increase was noticed in adverse events in the tiotropium group (OR 0.80, 95% CI 0.62-1.03, P = .08).

Conclusions: The addition of tiotropium to standard treatment regimens has significantly improved lung function without increasing adverse events in patients with inadequately controlled asthma. Long-term trials are required to assess the effects of the addition of tiotropium on asthma exacerbations and mortality.