Summary of acute exacerbations of chronic obstructive pulmonary disease (COPD) after withdrawing tiotropium in early COPD#

PlaceboTiotropiumRelative risk for tiotropium versus placebo (95% CI)p-value
Subjects n126136
Exacerbations per patient-year
 Total0.16±0.030.11±0.020.69 (0.42–1.13)0.14
 Mild0.06±0.020.03±0.010.42 (1.14–1.26)0.12
 Moderate0.06±0.010.06±0.010.98 (0.55–1.77)0.96
 Severe0.04±0.010.02±0.010.65 (0.27–1.58)0.34
 Of moderate or worse severity0.10±0.020.08±0.010.86 (0.54–1.38)0.52

Data are presented as mean±se, unless otherwise stated. #: exacerbation frequency per patient-year was referred to as the number of exacerbations for a single patient per year; : the relative risks in these categories were calculated using of Poisson regression corrected for treatment exposure and overdispersion.