Table 1. Demographic and clinical characteristics of COPD patients according to the GOLD 2014 and 2017 classification criteria.
| Subjects | Total cohort (N=1,278) | GOLD 2014 | GOLD 2017 | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| A (N=58) | B (N=288) | C (N=28) | D (N=904) | P value | A (N=71) | B (N=573) | C (N=15) | D (N=619) | P value | |||
| Age (years), mean ± SD | 62.4±8.4 | 58.4±7.7 | 62.9±8.6 | 59.9±8.5 | 62.6±8.3 | 0.001 | 59.1±8.1 | 62.2±8.4 | 58.0±7.1 | 63.1±8.4 | <0.001 | |
| Male, n (%) | 1,158 (90.6) | 54 (93.1) | 252 (87.5) | 27 (96.4) | 825 (91.3) | 0.154 | 67 (94.4) | 513 (89.5) | 14 (93.3) | 564 (91.1) | 0.516 | |
| BMI (kg/m2), mean ± SD | 22.3±3.4 | 23.7±3.1 | 23.4±3.4 | 21.6±2.6 | 21.9±3.4 | <0.001 | 23.4±3.2 | 22.7±3.5 | 21.6±2.2 | 21.9±3.4 | <0.001 | |
| Education level, n (%) | 0.053 | 0.001 | ||||||||||
| Primary school or below | 583 (45.6) | 23 (39.7) | 115 (39.9) | 13 (46.4) | 432 (47.8) | 29 (40.8) | 236 (41.2) | 7 (46.7) | 311 (50.2) | |||
| Junior high school | 505 (39.5) | 21 (36.2) | 125 (43.4) | 11 (39.3) | 348 (38.5) | 24 (33.8) | 238 (41.5) | 8 (53.3) | 235 (38.0) | |||
| Senior high school | 147 (11.5) | 10 (17.2) | 37 (12.8) | 3 (10.7) | 97 (10.7) | 13 (18.3) | 74 (12.9) | 0 | 60 (9.7) | |||
| University | 43 (3.4) | 4 (6.9) | 11 (3.8) | 1 (3.6) | 27 (3.0) | 5 (7.0) | 25 (4.4) | 0 | 13 (2.1) | |||
| Smoking history, n (%) | 0.004 | <0.001 | ||||||||||
| Never-smokers | 205 (16.0) | 6 (10.3) | 56 (19.4) | 2 (7.1) | 141 (15.6) | 6 (8.5) | 98 (17.1) | 2 (13.3) | 99 (16.0) | |||
| Former-smokers | 576 (45.1) | 22 (37.9) | 107 (37.2) | 11 (39.3) | 436 (48.2) | 27 (38.0) | 228 (39.8) | 6 (40.0) | 315 (50.9) | |||
| Current smokers | 497 (38.9) | 30 (51.7) | 125 (43.4) | 15 (53.6) | 327 (36.2) | 38 (53.5) | 247 (43.1) | 7 (46.7) | 205 (33.1) | |||
| Smoking pack-years* | 30 (30.0) | 25.5 (20.0) | 35.0 (35.0) | 34.0 (20.0) | 30.0 (30.0) | 0.411 | 30.0 (20.0) | 30.0 (32.5) | 20.0 (25.0) | 30.0 (30.0) | 0.433 | |
| FEV1% predicted, mean ± SD | 50.0±18.3 | 73.3±12.9 | 66.0±11.7 | 47.9±17.1 | 43.5±15.9 | <0.001 | 67.9±16.7 | 51.5±17.9 | 51.6±22.1 | 46.5±17.5 | <0.001 | |
| FEV1/FVC, mean ± SD | 48.1±12.1 | 60.2±7.4 | 56.3±8.7 | 54.0±9.9 | 44.5±11.4 | <0.001 | 58.9±8.2 | 48.5±12.1 | 54.8±10.5 | 46.2±11.7 | <0.001 | |
| GOLD stage, n (%) | <0.001 | <0.001 | ||||||||||
| 1 | 83 (6.5) | 16 (27.6) | 36 (12.5) | 1 (3.6) | 30 (3.3) | 16 (22.5) | 36 (6.3) | 1 (6.7) | 30 (4.8) | |||
| 2 | 510 (39.9) | 42 (72.4) | 252 (87.5) | 7 (25.0) | 209 (23.1) | 42 (59.2) | 252 (44.0) | 7 (46.7) | 209 (33.8) | |||
| 3 | 521 (40.8) | 0 | 0 | 17 (60.7) | 504 (55.8) | 12 (16.9) | 223 (38.9) | 5 (33.3) | 281 (45.4) | |||
| 4 | 164 (12.8) | 0 | 0 | 3 (10.7) | 161 (17.8) | 1 (1.4) | 62 (10.8) | 2 (13.3) | 99 (16.0) | |||
| Number of exacerbations in the past 12 months, n (%) | <0.001 | <0.001 | ||||||||||
| 0 | 475 (37.2) | 50 (86.2) | 211 (73.3) | 9 (32.1) | 205 (22.7) | 59 (83.1) | 416 (72.6) | 0 | 0 | |||
| 1 | 271 (21.1) | 8 (13.8) | 77 (26.7) | 9 (32.1) | 177 (19.6) | 12 (16.9) | 157 (27.4) | 5 (33.3) | 97 (15.7) | |||
| ≥2 | 532 (41.6) | 0 | 0 | 10 (35.7) | 522 (57.7) | 0 | 0 | 10 (66.7) | 522 (84.3) | |||
| Exacerbation rate/patient/year | 2.03 | 0.14 | 0.27 | 1.46 | 2.73 | 0.17 | 0.27 | 2.47 | 3.86 | |||
| Hospitalization rate/patient/year | 0.90 | 0 | 0 | 0.96 | 1.25 | 0 | 0 | 1.80 | 1.82 | |||
| mMRC, n (%) | <0.001 | <0.001 | ||||||||||
| 0 | 74 (5.8) | 24 (41.4) | 22 (7.6) | 3 (10.7) | 25 (2.8) | 26 (36.6) | 31 (5.4) | 1 (6.7) | 16 (2.6) | |||
| 1 | 313 (24.5) | 34 (58.6) | 96 (33.3) | 25 (89.3) | 158 (17.5) | 45 (63.4) | 162 (28.3) | 14 (93.3) | 92 (14.9) | |||
| 2 | 456 (35.7) | 0 | 116 (40.3) | 0 | 340 (37.6) | 0 | 218 (38.0) | 0 | 238 (38.4) | |||
| 3 | 371 (29.0) | 0 | 53 (18.4) | 0 | 318 (35.2) | 0 | 142 (24.8) | 0 | 229 (37.0) | |||
| 4 | 64 (5.0) | 0 | 1 (0.3) | 0 | 63 (7.0) | 0 | 20 (3.5) | 0 | 44 (7.1) | |||
| CAT, n (%) | <0.001 | <0.001 | ||||||||||
| 0–10 | 179 (14.0) | 58 (100.0) | 28 (9.7) | 28 (100.0) | 65 (7.2) | 71 (100.0) | 50 (8.7) | 15 (100.0) | 43 (6.9) | |||
| 11–20 | 805 (63.0) | 0 | 227 (78.8) | 0 | 578 (63.9) | 0 | 423 (73.8) | 0 | 382 (61.7) | |||
| 21–30 | 276 (21.6) | 0 | 33 (11.5) | 0 | 243 (26.9) | 0 | 96 (16.8) | 0 | 180 (29.1) | |||
| 31–40 | 18 (1.4) | 0 | 0 | 0 | 18 (2.0) | 0 | 4 (0.7) | 0 | 14 (2.3) | |||
Groups A–D: COPD patients were stratified into group A to D twice according to the GOLD 2014 and 2017 comprehensive assessments. *, non-normal distribution data were expressed as median (interquartile range). GOLD, Global Initiative for Chronic Obstructive Pulmonary Disease; SD, standard deviation; BMI, body mass index; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; mMRC, modified Medical Research Council; CAT, COPD Assessment Test; COPD, chronic obstructive pulmonary disease.