Exercise Capacity
After 4 y, the 6MWD in the management group increased by 16 _ 7 m (mean _ SD), whereas the 6MWD
in the control group decreased by 27 _ 12 m. This difference was statistically significant (difference of 43 m, 95% CI 12–75, P _ .001) (see Table 5). The 6MWD
increased significantly in all management subgroups with the exception of the grade I subgroup; in contrast, the 6MWD decreased significantly in all control subgroups (see Table 6).