Comparison of tiotropium and salmeterol for treating COPD: a systematic review and meta-analysis

Introduction: Tiotropium and salmeterol showed some potential in alleviating chronic obstructive pulmonary disease (COPD). But the results remained controversial. We conducted a systematic review and meta-analysis to compare the efficacy and safety of tiotropium and salmeterol in patients with COPD. Methods: PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases were systematically searched. Randomized controlled trials (RCTs) assessing the effect of tiotropium versus salmeterol on COPD were included. Two investigators independently searched articles, extracted data, and assessed the quality of included studies. The primary outcome was exacerbation of the disease. Meta-analysis was performed using the fixed or random-effect model when appropriate. Results: Four RCTs involving 9257 patients were included in the meta-analysis. Overall, compared with salmeterol in patients with COPD, tiotropium could significantly reduce exacerbation (RR = 0.89; 95% CI = 0.86 to 0.92; P<0.001), and improved average FEV1 response over 12 h (mean difference = 56.95; 95% CI = 17.75 to 96.15; P = 0.004), peak FEV1 (mean difference = 64.44; 95% CI = 28.18 to 100.70; P = 0.0005) as well as SGRQ scores improvement at least 4 units (RR = 1.18; 95% CI = 1.05 to 1.34; P = 0.007). In addition, less serious adverse events was found following tiotropium treatment than those of salmeterol (RR = 0.77; 95% CI = 0.66 to 0.89; P = 0.0005). Conclusion: Compared to salmeterol treatment, tiotropium treatment was associated with significantly reduced exacerbation, and improved lung function in patients with COPD.