Figure 1.

Flow diagram of the patients included in the analyses. For details on each of the studies, see Table E1. *NETT evaluated effectiveness of LVRS and will be analyzed separately in selected analyses. 6MWT = 6-minute-walk distance test; BODE = Body mass index, Obstruction, Dyspnea, and Exercise index; CHS = Cardiovascular Health Study; COPD = chronic obstructive pulmonary disease; ECLIPSE = Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints; GOLD = Global Initiative for Chronic Obstructive Lung Disease; LVRS = lung volume reduction surgery; NETT = National Emphysema Therapy Trial; VATS = video-assisted thoracoscopic surgery.