Estimated cumulative mortality in the study sample split by alveolar volume (V
) as % predicted: V
<80% (red step curve); V
≥80% (blue step curve). Estimates are adjusted for age, NYHA class III-IV, cardiothoracic ratio >0.5, NT-proBNP, persistent atrial fibrillation, DLCO as % predicted, and COPD comorbidity. P-value by log-rank test = 0.032.