Efficacy of Tiotropium Inhalation Powder in African-American Patients with Chronic Obstructive Pulmonary Disease

Background: Responsiveness to pharmacologic agents may differ among subpopulations compared with the general population. In patients of African descent, possible differences have been observed for inhaled beta-agonists. However, pharmacologic responsiveness to a long-acting anticholinergic has not been prospectively evaluated. Methods: An 8-week, randomized, placebo-controlled clinical trial was conducted to assess the efficacy of the once-daily, inhaled anticholinergic tiotropium in COPD patients of African descent. African-American COPD patients >= 40 years, FEV1 <= 65% predicted, FEV1/FVC <= 70% were included. Spirometry (pre-study drug, and 0.5, 1, 2 and 3 hours post-dose) and the University of California, San Diego Shortness of Breath Questionnaire (SOBQ) were performed at baseline and at 4 and 8 weeks. Data on use of rescue medication and on adverse events (including COPD exacerbations) were also collected. Results: Randomized patients (n = 166) were (mean +/- SD) 62.5 +/- 9.3 years; baseline mean FEV1 1.02 +/- 0.37 L (41 +/- 13% predicted); 67.5% were male. A total of 160 patients were eligible for efficacy evaluation. At 8 weeks, mean FEV1 AUC(0-3) response was 180 mL greater with tiotropium (n = 78) than with placebo (n = 82), (p < 0.0001). Difference (tiotropium-placebo) for mean peak FEV1 response was 182 mL (p < 0.0001) and 122 mL (p = 0.002) for mean trough FEV1 response. There were no significant differences in SOBQ or use of rescue medication between the groups. No patients in the tiotropium group experienced a COPD exacerbation compared with 12 in patients receiving placebo. Conclusion: Tiotropium significantly improved pulmonary function in African-American COPD patients.