All study participants | All COPD patients | COPD GOLD stage | Controls | p-value# | p-value¶ | ||||
A | B | C | D | ||||||
Subjects | 129 | 107 | 6 | 52 | 4 | 45 | 22 | ||
Pulmonary function parameters | |||||||||
FEV1 L+ | 1.80±0.93 | 1.57±0.77 | 1.76±0.86 | 2.01±0.74 | 1.16±0.20 | 1.26±0.37 | 3.02±0.75 | <0.001 | <0.001 |
FEV1 % pred+ | 63.7±25.6 | 56.7±21.8 | 70.3±15.0 | 70.6±14.2 | 48.1±2.5 | 45.2±14.1 | 98.2±14.3 | <0.001 | <0.001 |
FVC L | 2.88±1.13 | 2.69±1.01 | 3.11±1.41 | 3.14±1.06 | 2.24±1.00 | 2.75±0.60 | 3.85±1.00 | <0.001 | <0.001 |
FVC % pred | 77.9±21.1 | 73.7±20.2 | 91.5±2.2 | 85.0±16.0 | 67.2±11.9 | 75.5±16.2 | 96.7±11.9 | <0.001 | <0.001 |
FEV1/FVC ratio+ | 62.9±15.9 | 59.7±15.3 | 57.5±10.9 | 65.6±10.4 | 56.9±18.1 | 48.7±13.5 | 79.7±6.9 | <0.001 | <0.001 |
RV L | 3.68±1.57 | 3.92±1.57 | 3.76±1.40 | 2.97±0.87 | 3.58±1.20 | 4.28±1.15 | 2.51±0.91 | <0.001 | <0.001 |
RV % pred | 163.9±68.5 | 174.8±69.2 | 166.1±50.4 | 132.8±40.7 | 141.7±23.5 | 182.7±39.9 | 111.3±34.8 | <0.001 | <0.001 |
RTOT kPa·s·L−1 | 0.43±0.28 | 0.47±0.29 | 0.34±0.14 | 0.34±0.18 | 0.46±0.08 | 0.63±0.33 | 0.23±0.10 | <0.001 | <0.001 |
RTOT % pred | 143.1±95.2 | 156.9±98.2 | 113.9±47.9 | 113.5±60.8 | 153.6±27.3 | 213.3±113.9 | 77.2±32.6 | <0.001 | <0.001 |
DLCO % pred | 55.8±19.6 | 48.5±16.0 | 74.9±8.2 | 53.9±11.4 | 47.7±15.3 | 36.3±15.2 | 77.1±13.4 | <0.001 | <0.001 |
DLCO/VA % pred | 67.8±24.2 | 60.5±22.0 | 88.2±7.1 | 69.4±16.1 | 70.2±18.5 | 47.5±18.2 | 90.7±15.7 | <0.001 | <0.001 |
Capillary blood gas analysis | |||||||||
PO2 mmHg | 68.1±12.3 | 66.2±12.6 | 70.1±5.6 | 64.6±8.5 | 64.0±3.0 | 61.2±8.0 | 77.0±5.7 | 0.001 | <0.001 |
PCO2 mmHg | 36.0±6.5 | 36.2±6.8 | 33.5±6.2 | 34.4±7.3 | 37.4±0.8 | 38.1±4.8 | 35.0±4.6 | 0.16 | 0.42 |
SO2 % | 94.0±2.9 | 93.6±3.0 | 95.7±0.7 | 93.9±3.3 | 94.0±2.0 | 91.8±2.9 | 96.0±1.2 | <0.001 | <0.001 |
Data are presented as n or mean±sd, unless otherwise stated. COPD: chronic obstructive pulmonary disease; GOLD: Global Initiative for Chronic Obstructive Lung Disease; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; RV: residual volume; RTOT: total resistance; DLCO: diffusion capacity of the lung for carbon monoxide; VA: alveolar volume; PO2: oxygen tension; PCO2: carbon dioxide tension; SO2: oxygen saturation. #: intercohortal comparison was performed by defining controls as the COPD GOLD 0 group, p-values refer to data comparison between all five groups (COPD GOLD 0 through D); ¶: p-values refer to data comparison between the entire COPD group and controls; +: based on post-bronchodilator FEV1.