Table 1.
Demographic characteristics of participants
| Variables | Control group (n=30) | Mild COPD (n=29) | Moderate COPD (n=30) | Severe COPD (n=24) | F/χ2-value | P-value |
|---|---|---|---|---|---|---|
| Age (years) | 57.43±8.66 | 59.38±8.27 | 60.90±10.63 | 63.42±9.53 | 1.96 | 0.12a |
| Sex (M/F) | (21/9) | (13/16) | (16/14) | (17/7) | 7.01 | 0.07b |
| Education (years) | 9.20±2.29 | 9.86±2.66 | 9.60±2.06 | 9.25±2.80 | 0.46 | 0.71a |
| BMI (kg/m2) | 23.9±3.02 | 24.20±4.40 | 23.25±4.20 | 22.16±3.41 | 1.48 | 0.22a |
| Smoking history (Y/N) | (19/11) | (12/17) | (15/15) | (16/8) | 4.63 | 0.20b |
| Smoking index (packs/year) | 22.79±6.91 | 21.08±9.06 | 24.27±7.04 | 25.00±5.05 | 0.84 | 0.47a |
| FEV1 (%) | 106.62±22.86 | 85.47±4.17* | 66.23±8.21*,# | 38.18±7.39*,#,+ | 132.87 | 0.001a |
| Blood gas analysisc | ||||||
| PH | 7.40±0.01 | 7.40±0.02 | 7.40±0.01 | 7.40±0.02 | 0.104 | 0.958a |
| PaO2 (mmHg) | 115.65±8.92 | 101.27±8.64* | 76.90±5.79*,# | 66.97±3.75*,#,+ | 163.19 | 0.001a |
| SaO2 (%) | 38.88±2.73 | 38.81±3.99 | 39.19±2.54 | 40.05±4.21+ | 5.15 | 0.003a |
| PaCO2 (mmHg) | 98.22±0.51 | 97.09±0.79* | 94.59±0.97*,# | 92.04±1.38*,#,+ | 120.29 | 0.001a |
Notes: Data are presented as the mean ± standard deviation, except where indicated otherwise.
a
ANOVA;
b
Chi-square test;
c
Control group (n=15), mild COPD (n=16), moderate COPD (n=22), severe COPD (n=17).
*
P<0.05 versus control group;
#
P<0.05 versus mild COPD;
+
P<0.05 versus moderate COPD.
Abbreviations: ANOVA, analysis of variance; BMI, body mass index; F, female; FEV1, forced expiratory volume in 1 second; M, male; N, no; PaCO2, arterial partial pressure of carbon dioxide; PaO2, arterial partial pressure of oxygen; PH, power of hydrogen; SaO2, oxygen saturation; Y, yes.