Table 1.
Baseline demographics of study participants (before switching to electronic cigarettes)
| Parameter | COPD controls (n=22) | COPD EC users (n=22) | Baseline p-value between groups |
|---|---|---|---|
| Age¥ | 65.2 (±5.6) | 66.5 (±6.8) | 0.518 |
| Sex | 19 M, 3 F | 18 M, 4 F | – |
| COPD GOLD staging | |||
| Stage 1 | 2 | 2 | – |
| Stage 2 | 5 | 6 | – |
| Stage 3 | 10 | 9 | – |
| Stage 4 | 5 | 5 | – |
| Post-BD FEV1* (L) | 1.47 (1.17, 1.69) | 1.25 (0.97, 1.82) | 0.445 |
| Post-BD FVC* (L) | 2.34 (2.09, 2.63) | 2.49 (2.3, 2.65) | 0.787 |
| %FEV1/FVC¥ | 59.7 (±7.8) | 56.2 (±10.7) | 0.221 |
| Pack-years of smoking¥ | 51.8 (±10.4) | 52.2 (±11.1) | 0.900 |
| Cig/day¥ | 20.8 (±4.6) | 21.9 (±4.5) | 0.221 |
| CAT score* | 20 (17.3, 24.8) | 21.0 (17.3, 25.0) | 0.832 |
| COPD exacerbations¥ | 2.1 (±1.1) | 2.3 (±0.9) | 0.657 |
| 6MWD* (m) | 284.5 (217.5, 365) | 289.5 (186.5, 344.8) | 0.817 |
Notes:
*
Median (interquartile range);
¥
mean (± standard deviation).
Abbreviations: 6MWD, 6-minute walk distance; BD, bronchodilator; CAT, COPD Assessment Tool; Cig, conventional cigarettes; COPD, chronic obstructive pulmonary disease; EC, electronic cigarette; F, female; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease; M, male.