Table 3. Risk factors relevant to frequency of COPD exacerbations.
| Clinical characteristics | Frequency of COPD exacerbations | ||
|---|---|---|---|
| 0–1 (n=464) | ≥2 (n=637) | P | |
| Age (year) | 66.1±10.8 | 66.5±11.7 | 0.615 |
| Male | 294 (63.4) | 432 (67.8) | 0.123 |
| Height (cm) | 164.8±8.8 | 165.5±7.8 | 0.145 |
| Weight (kg) | 61.8±12.3 | 61.4±12.0 | 0.597 |
| BMI (kg/m2) | 22.7±3.9 | 22.4±4.0 | 0.137 |
| Smoking status | 0.049 | ||
| Current- | 112 (24.1) | 138 (21.7) | |
| Ex- | 195 (42.0) | 315 (49.5) | |
| Never- | 157 (33.8) | 184 (28.9) | |
| Smoking index (pack·year) | 21.7±24.3 | 23.8±25.8 | 0.173 |
| Chronic bronchitis | 360 (77.6) | 530 (83.2) | 0.019 |
| mMRC dyspnea score | <0.001 | ||
| 0 | 66 (14.2) | 32 (5.0) | |
| 1 | 195 (42.0) | 187 (29.4) | |
| 2 | 117 (25.2) | 229 (35.9) | |
| 3 | 59 (12.7) | 120 (18.8) | |
| 4 | 27 (5.8) | 69 (10.8) | |
| GOLD stage | <0.001 | ||
| I | 24 (5.2) | 36 (5.7) | |
| II | 163 (35.1) | 163 (25.1) | |
| III | 183 (39.4) | 241 (37.8) | |
| IV | 94 (20.3) | 197 (30.9) | |
Data are presented as mean ± SD or number (%). COPD, chronic obstructive pulmonary disease; BMI, body mass index; mMRC, modified Medical Research Council; GOLD, Global Initiative for Chronic Obstructive Lung Disease.