Table 3.
Stratified comparison of respiratory symptoms, respiratory illnesses, and environmental exposures between countries in GOLD spirometry grade 3 (severe COPD) versus 4 (very severe COPD) (N [%] or mean ± standard deviation)
| FEV1% <30
|
FEV1% ≥30
|
|||||||
|---|---|---|---|---|---|---|---|---|
| Poland (n=161) |
Korea (n=46) |
USA (n=106) |
p-value | Poland (n=155) |
Korea (n=127) |
USA (n=233) |
p-value | |
| Usual cough | 123 (76.4) | 17 (37.0) | 50 (47.2) | <0.0001 | 116 (74.8) | 59 (46.5) | 103 (44.2) | <0.0001 |
| Usual phlegm | 133 (82.6) | 29 (63.0) | 58 (54.7) | <0.0001 | 117 (75.5) | 77 (60.6) | 123 (52.8) | <0.0001 |
| Chronic bronchitis | 86 (53.4) | 11 (23.9) | 41 (38.7) | 0.0007 | 79 (51.0) | 37 (29.1) | 86 (36.9) | 0.0006 |
| Wheezing | 128 (79.5) | 31 (67.4) | 89 (84.0) | 0.07 | 126 (81.3) | 85 (66.9) | 192 (82.4) | 0.002 |
| Attacks of wheezing | 70 (43.5) | 25 (54.4) | 41 (38.7) | 0.2 | 67 (43.2) | 71 (55.9) | 114 (48.9) | 0.1 |
| mMRC dyspnea* | 3.53±0.82 | 3.14±0.95 | 3.08±1.03 | 0.0005 | 3.03±1.07 | 2.23±1.22 | 2.61±1.23 | <0.0001 |
| Pneumonia | 98 (60.9) | 11 (23.9) | 61 (57.6) | <0.0001 | 86 (55.5) | 27 (21.3) | 167 (71.7) | <0.0001 |
| Tuberculosis | 14 (8.7) | 22 (47.8) | 0 (0.0) | <0.0001 | 20 (12.9) | 45 (35.4) | 1 (0.4) | <0.0001 |
| Attacks of bronchitis | 112 (69.6) | 4 (8.7) | 66 (62.3) | <0.0001 | 91 (58.7) | 4 (3.2) | 135 (57.9) | <0.0001 |
| Physician-diagnosed asthma | 2 (1.2) | 22 (47.8) | 25 (23.6) | <0.0001 | 3 (1.9) | 54 (42.5) | 83 (35.6) | <0.0001 |
| Lung trouble before age 16 | 27 (16.8) | 3 (6.5) | 13 (12.3) | 0.2 | 22 (14.2) | 8 (6.3) | 32 (13.7) | 0.07 |
| Pack-years | 45.8±22.3 | 40.0±13.7 | 65.4±37.9 | <0.0001 | 43.1±22.7 | 46.9±26.0 | 60.6±32.3 | <0.0001 |
| Age when started smoking | 18.6±3.6 | 21.1±3.4 | 16.4±4.9 | <0.0001 | 18.7±3.9 | 20.9±6.1 | 16.7±4.9 | <0.0001 |
| Occupational gas/fume exposure | 67 (42.1) | 12 (28.6) | 46 (43.8) | 0.2 | 68 (43.9) | 8 (7.0) | 95 (41.3) | <0.0001 |
Notes:
*
For mMRC dyspnea analysis, n=42 (Korea) and n=88 (USA) in very severe (FEV1 <30%) analyses; and n=110 (Korea) and n=176 (USA) in severe (FEV1 ≥30%) analyses.
Abbreviations: mMRC, modified Medical Research Council; COPD, chronic obstructive pulmonary disease; GOLD, Global initiative for chronic Obstructive Lung Disease; FEV1, forced expiratory volume in 1 second.