Figure 2.

Differences in secondary outcomes across quartiles of exercise capacity (6-min-walk distance [6MWD]), dyspnea (San Diego Shortness of Breath Questionnaire [SOBQ]), and lung function (FEV₁ percent predicted ). BDI-II = Beck Depression Inventory-II. *P < 0.05 for change over quartiles. ^#P < 0.05 for differences between individual quartiles compared with the reference quartile. The vertical bars represent mean values for each outcome. The error bars represent SE. To report post hoc comparisons, we used quartile 4 with the best walk distance, dyspnea, and lung function as the reference quartile.