Mortality ( n = @ ) was compared by treatment allocation during @ months ( interquartile range : @ to @ months ) of follow-up for subjects able ( n = @ ) and unable ( n = @ ) to walk @ m in @ min and with less ( Physical Ability Score -LSB- PAS -RSB- > @ , n = @ ) and more ( PAS @ , n = @ ) limitation by dyspnea or fatigue .