Figure 1.
Probability of death as a function of the number of months after randomization (Kaplan-Meier estimates). High-risk patients were defined as having an FEV1 not greater than 20% predicted and either homogeneous emphysema or DLCO (diffusing capacity for carbon monoxide) not exceeding 20% predicted. Low baseline exercise capacity was defined as a maximal workload at or below the sex-specific 40th percentile (25 W for women and 40 W for men); high exercise capacity was defined as a workload above this threshold. P values were derived by Fisher's exact test for e comparison between groups over a mean follow-up period of 29.2 months. (Reprinted by permission from Reference 17.)