Incidence of serious adverse events was similar between groups ( 167 [ 23 % ] patients on QVA149 , 179 [ 24 % ] on glycopyrronium , and 165 [ 22 % ] on tiotropium ) ; COPD worsening was the most frequent serious adverse event ( 107 [ 15 % ] patients on QVA149 , 116 [ 16 % ] on glycopyrronium , 87 [ 12 % ] on tiotropium ) .