Improvement in exercise capacity (increase in maximal work > 10 W above the patient's postrehabilitation baseline) at 1, 2, and 3 years postrandomization to lung volume reduction surgery (LVRS) (open columns) or medical therapy (solid columns) for (a) all patients and (b–d) non–high-risk and upper lobe–predominant patient subgroups. Shown below each graph are the numbers of patients evaluated, the odds ratio for improvement (LVRS:Medical), and the Fisher's exact P value for difference in proportion improved. Patients who died or who did not complete the assessment were considered not improved. This is an intention-to-treat analysis. (a) All patients (n = 1,218). (b) Non–high-risk patients (n = 1,078). (c) Upper lobe–predominant and low baseline exercise capacity (n = 290). (d) Upper lobe–predominant and high exercise capacity (n = 419). Reprinted by permission from Reference 18.