Effect of tiotropium vs. salmeterol on exacerbations: GOLD II and maintenance therapy naïve patients

The objective of this study was to investigate the effect of tiotropium compared with salmeterol on exacerbations in patients with moderate (Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage II) chronic obstructive pulmonary disease (COPD) and those naïve to maintenance respiratory therapy in the 1-year Prevention Of Exacerbations with Tiotropium in COPD (POET-COPD(®)) trial (NCT00563381). Time to first exacerbation (primary endpoint) and rates of exacerbations were analyzed using exploratory Cox and Poisson regression (adjusting for time on treatment). Of 7376 randomized patients, 3614 were GOLD stage II (tiotropium n = 1781; salmeterol n = 1833) and 1343 were maintenance therapy naïve (tiotropium n = 672; salmeterol n = 671). Tiotropium significantly increased time to first exacerbation vs. salmeterol in GOLD stage II patients (hazard ratio [HR], 0.88; 95% confidence interval [CI]: 0.79-0.99; p = 0.028) and maintenance therapy naïve patients (HR, 0.79; 95% CI, 0.65-0.97; p = 0.028). Annual exacerbation rates were also significantly lower with tiotropium in the maintenance naïve subgroup compared with salmeterol (rate ratio [RR], 0.77; 95% CI, 0.63-0.94; p = 0.012). In the GOLD stage II subgroup, the rate of hospitalized exacerbations per year was significantly lower with tiotropium than with salmeterol (RR, 0.70; 95% CI, 0.57-0.85; p < 0.001); tiotropium also significantly prolonged time to first hospitalized exacerbation versus salmeterol in this subgroup (HR, 0.66; 95% CI, 0.48-0.91; p = 0.012). In conclusion, results from this prespecified subgroup analysis support the selection of tiotropium as first-choice maintenance therapy for patients with GOLD stage II COPD.