Figure 2–

The Kaplan–Meier survival curves, adjusted for age, arterial oxygen partial pressure, carbon monoxide transfer factor % pred quartiles, forced vital capacity (FVC) % pred, forced expiratory volume in 1 s to FVC ratio, total lung capacity (TLC) % pred, functional residual capacity % pred, inspiratory capacity to TLC ratio, residual volume % pred, body mass index and arterial carbon dioxide partial pressure for the four population groups, categorised by Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages. Survival only differed significantly between GOLD stage II and IV (p = 0.04).