Table 1.
Baseline characteristics and univariate analysis
| Variable | All patients (N=984) |
Alive (N=388) |
Dead (N=596) |
P-value |
|---|---|---|---|---|
| Female, n (%) | 436 (44.3) | 191 (49.2) | 245 (41.1) | 0.013 |
| Age, mean years ± SD | 62.7±12.1 | 58.2±13.3 | 65.6±10.3 | <0.0001 |
| BMI, mean ± SD | 24.2±4.6 | 25.0±4.5 | 23.7±4.6 | <0.0001 |
| FEV1/FVC%, mean ± SD | 46.8±13.4 | 51.8±13.7 | 43.5±12.2 | <0.0001 |
| FEV1 predicted %, mean ± SD | 50.2±25.49 | 57.9±26.79 | 45.1±23.29 | <0.0001 |
| Stage (GOLD) | <0.0001 | |||
| Mild, ≥80% of predicted, n (%) | 162 (16.5) | 106 (27.3) | 56 (9.4) | |
| Moderate, 50%–79% of predicted, n (%) | 265 (26.9) | 107 (27.6) | 158 (26.5) | |
| Severe, 30%–49% of predicted, n (%) | 283 (28.8) | 99 (25.5) | 184 (30.9) | |
| Very severe, <30% of predicted, n (%) | 274 (27.8) | 76 (19.6) | 198 (33.2) | |
| % TLC, mean ± SD | 135.15±11.12 | 133.7±10.17 | 136.1±11.56 | 0.001 |
| % DLCO, mean ± SD | 43.2±17.74 | 49.9±17.59 | 38.8±16.43 | <0.0001 |
| DLCO <22%, n (%) | 126 (12.8) | 21 (5.4) | 105 (17.6) | <0.0001 |
| % IC, mean ± SD | 92.0±27.74 | 98.8±26.79 | 87.7±27.53 | <0.0001 |
| IC ≥80%, n (%) | 632 (64.2) | 295 (76.0) | 337 (56.5) | <0.0001 |
| BMI | <0.0001 | |||
| Low, <20, n (%) | 176 (17.9) | 52 (13.4) | 124 (20.8) | |
| Normal, 20 to <25, n (%) | 407 (41.4) | 144 (37.1) | 263 (44.1) | |
| High ≥25, n (%) | 401 (40.7) | 192 (49.5) | 209 (35.1) | |
| IC/TLC, mean % ± SD | 28.7±9.8 | 32.0±10.2 | 26.6±8.9 | <0.0001 |
| IC/TLC ≤25%, n (%) | 395 (40.1) | 99 (25.5) | 296 (49.7) | <0.0001 |
Notes: Baseline characteristics of survivors and nonsurvivors. Subjects who died were more likely to be male, had greater airflow obstruction, an IC/TLC ≤25%, lower BMI, and were older.
Abbreviations: BMI, body mass index; DLCO, diffusing capacity of the lungs for carbon monoxide; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease; IC, inspiratory capacity; SD, standard deviation; TLC, total lung capacity.