Table 1. Baseline characteristics of the KOCOSS subjects.
| Variables | No. of subjects | No. (%) or observation |
|---|---|---|
| Age (yr, mean ± SD) | 956 | 69.9 ± 7.8 |
| Male, No. (%) | 956 | 872 (91.2) |
| BMI (kg/m2, mean ± SD) | 926 | 22.7 ± 3.4 |
| Smoking, pack/yr, (mean ± SD) | 812 | 43.9 ± 25.1 |
| Current smoker (%) | 938 | 262 (27.9) |
| Former smoker (%) | 596 (63.5) | |
| Non – smoker (%) | 80 (8.5) | |
| Number of acute exacerbation during one year before enroll | 942 | |
| Mean number (mean ± SD) | 0.58 ± 1.6 | |
| 0 (%) | 692 (73.5) | |
| 1 (%) | 145 (15.4) | |
| ≥ 2 (%) | 105 (11.2) | |
| Number of comorbidities (mean ± SD) | 958 | 1.7 ± 1.4 |
| 0 | 208 (21.7) | |
| 1 | 256 (26.7) | |
| 2 | 258 (26.9) | |
| 3 | 145 (15.1) | |
| 4 | 51 (55.3) | |
| 5 | 28 (2.92) | |
| 6 | 7 (0.7) | |
| 7 | 5 (0.5) | |
| Education level | 945 | |
| Middle school and below | 540 (57.1) | |
| High school | 280 (29.6) | |
| College and above | 125 (13.2) | |
| Lung function | ||
| FEV1/FVC (%, mean ± SD) | 916 | 49.0 ± 12.0 |
| Post bronchodilator FEV1 (%, mean ± SD) | 914 | 55.8 ± 16.7 |
| Post bronchodilator FEV1 (L, mean ± SD) | 923 | 1.5 ± 0.58 |
| FVC (L, mean ± SD) | 923 | 3.06 ± 0.79 |
| TLC (L, mean ± SD) | 596 | 5.6 ± 0.8 |
| 6MWD (meters, mean ± SD) | 737 | 365.6 ± 117.3 |
| Subjects requiring oxygen during/after 6MWD | 958 | 2 (0.3) |
| Symptom scores | 958 | |
| CAT (mean ± SD) | 913 | 15.5 ± 7.7 |
| CAT score | 213 (23.3) | |
| CAT score ≥ 10 | 700 (76.7) | |
| mMRC score (mean ± SD) | 951 | 1.6 ± 1.0 |
| mMRC score | 515 (54.2) | |
| mMRC score ≥ 2 | 436 (45.8) | |
| Questionnaire (SGRQ-C) | ||
| Symptom | 947 | 44.2 ± 20.9 |
| Activity | 946 | 46.0± 27.3 |
| Impact | 947 | 25.7 ± 23.3 |
| Total | 944 | 34.8 ± 19.6 |
| GOLD stage (I to IV) | 914 | |
| I | 51 (5.6) | |
| II | 520 (56.9) | |
| III | 291 (31.8) | |
| IV | 52 (5.7) | |
| GOLD (A to D) | 920 | |
| A | 122 (12.8) | |
| B | 399 (42.0) | |
| C | 48 (5.1) | |
| D | 351 (36.9) |
SD, standard deviation; BMI, body mass index; FEV1, forced expiratory volume in one second; FVC, forced vital capacity; TLC, total lung capacity; 6MWD, six minutes walk distance test; CAT, COPD assessment test; mMRC, modified Medical Research Council dyspnea scale; SGRQ-C, St. George’s respiratory questionnaire; GOLD, global initiative for chronic obstructive lung disease.