TABLE 3.
MORTALITY AMONG ALL PATIENTS AND IN SUBGROUPS
| 90-Day Mortality |
Total Mortality |
||||||||
| Surgery Group | Medical-Therapy Group | Surgery Group |
Medical-Therapy Group |
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| Patients | No. of Deaths/Total No. (% [95% CI]) | No. of Deaths/Total No. (% [95% CI]) | P Value | No. of Deaths/Total No. | No. of Deaths/Person-Year | No. of Deaths/Total No. | No. of Deaths/Person-Year | Risk Ratio | P Value |
| All patients | 48/608 (7.9 [5.9−10.3]) | 8/610 (1.3 [0.6−2.6]) | <0.001 | 157/608 | 0.11 | 160/610 | 0.11 | 1.01 | 0.90 |
| High-risk* | 20/70 (28.6 [18.4−40.6]) | 0/70 (0 [0−5.1]) | <0.001 | 42/70 | 0.33 | 30/70 | 0.18 | 1.82 | 0.06 |
| Other | 28/538 (5.2 [3.5−7.4]) | 8/540 (1.5 [0.6−2.9]) | 0.001 | 115/538 | 0.09 | 130/540 | 0.10 | 0.89 | 0.31 |
| Subgroups† | |||||||||
| Patients with predominantly upper lobe emphysema | |||||||||
| Low exercise capacity | 4/139 (2.9 [0.8−7.2]) | 5/151 (3.3 [1.1−7.6]) | 1.00 | 26/139 | 0.07 | 51/151 | 0.15 | 0.47 | 0.005 |
| High exercise capacity | 6/206 (2.9 [1.1−6.2]) | 2/213 (0.9 [0.1−3.4]) | 0.17 | 34/206 | 0.07 | 39/213 | 0.07 | 0.98 | 0.70 |
| Patients with predominantly non–upper lobe emphysema | |||||||||
| Low exercise capacity | 7/84 (8.3 [3.4−16.4]) | 0/65 (0 [0−5.5]) | 0.02 | 28/84 | 0.15 | 26/65 | 0.18 | 0.81 | 0.49 |
| High exercise capacity | 11/109 (10.1 [5.1−17.3]) | 1/111 (0.9 [0.02−4.9]) | 0.003 | 27/109 | 0.10 | 14/111 | 0.05 | 2.06 | 0.02 |
Definition of abbreviation: CI = confidence interval.
Reprinted by permission from Reference 17.
Mortality was measured from the date of randomization in both treatment groups. Total mortality rates are based on a mean follow-up of 29.2 months. P values were calculated by Fisher's exact test. Risk ratios are for the risk in the surgery group as compared with the risk in the medical-therapy group. A low baseline exercise capacity was defined as a postrehabilitation baseline maximal workload at or below the sex-specific 40th percentile (25 W for women and 40 W for men); a high-exercise capacity was defined as a workload above this threshold.
High-risk patients were defined as those with an FEV1 that was 20% or less of the predicted value and either homogeneous emphysema on computed tomography or a carbon monoxide diffusing capacity that was 20% or less of the predicted value.
High-risk patients were excluded from the subgroup analyses. For total mortality, P for interaction = 0.004; this P value was derived from binary logistic-regression models with terms of treatment, subgroup, and the interaction between the two, with the use of an exact-score test with 3 degrees of freedom. Other factors that were considered as potential variables for the definition of subgroups included the baseline FEV1, carbon monoxide diffusing capacity, partial pressure of arterial carbon dioxide, residual volume to total lung capacity, ratio of expired ventilation in 1 minute to carbon dioxide excretion in 1 minute, distribution of emphysema (heterogeneous vs. homogeneous), perfusion ratio, Health-related Quality of Life score, Quality of Well-Being score, age, race or ethnic group, and sex.