“…The duration of the trials ranged from 4 to 156 weeks, with 18 trials being longer than 52 weeks in duration [ 3 , 15 , 22 – 26 , 28 , 30 , 32 , 33 , 35 , 39 , 42 , 44 , 45 , 47 ]. Most trials enrolled participants with severe COPD, as the mean predicted FEV1 of the participants was >50% in 7 trials [ 15 , 23 , 29 , 33 , 37 , 38 , 47 ] compared to ≤50% in 17 trials [ 3 , 16 , 17 , 22 , 24 , 28 , 30 – 32 , 34 , 36 , 45 , 46 , 48 ], whereas 7 trials did not report the details of FEV1.…”