Table 1

Participant characteristics

VariableCOPD, n=50
Age, years66 (59, 70)
Gender, female/male, n23/27
BMI, kg/m223.9 (21.3, 27.0)
Waist–hip ratio
 Females0.89 (0.83, 0.94)
 Males1.0 (0.94, 1.04)
Pulmonary function
FEV1, L0.78 (0.59, 1.0)
FEV1, % predicted28.8 (24.8, 35.1)
FVC, L1.69 (1.19, 2.28)
FVC, % predicted50.1 (41.6, 63.7)
FEV1/FVC, %45.8 (40.8, 53.7)
TLC, L7.7 (7.0, 9.1)
TLC, % predicted137.0 (121.8, 154.8)
FRCpleth, L6.8 (5.9, 7.6)
FRCpleth, % predicted213.6 (182.0, 251.8)
RV, L5.9 (5.0, 7.0)
RV, % predicted269.9 (218.1, 335.6)
RV/TLC, %77.1 (68.6, 82.7)
RV/TLC, % predicted188.5 (172.1, 206.9)
Raw, kPa s L-10.87 (0.63, 1.10)
Raw, % predicted289.6 (209.6, 367.3)
sRaw, kPa s6.0 (4.4, 8.9)
sRaw, % predicted575.8 (397.4, 844.0)
GOLD grade
 III, n23 (46)
 IV, n27 (54)
Blood gases, room air—rest
pH7.41 (7.39, 7.42)
PO2, mm Hg54.7 (51.0, 57.7)
PCO2, mm Hg44.2 (38.2, 47.8)
Exercise capacity
6-minute walk distance, m303.5 (245.0, 371.5)
6-minute walk distance, % predicted48.4 (38.5, 59.5)
Incremental shuttle walk test, m205.0 (130.0, 325.0)
Long-term oxygen therapy
Period of application, months47 (18, 79)
O2-flow rates, L
 Rest1.75 (1.0, 2.9)
 Night2.0 (1.0, 2.9)
  • Data presented as median (interquartile range (IQR)) or number.

  • %, per cent; BMI, body mass index; FEV1, forced expiratory volume in 1 s; FRC, functional residual capacity; FVC, forced vital capacity; kg, kilograms; kg/m2, kilograms per metre squared; L, litre; m, metres; mm Hg, millimetres of mercury; n, number; PCO2, partial pressure of carbon dioxide; pH, potential of hydrogen; PO2, partial pressure of oxygen; Raw, airway resistance; RV, residual volume; sRaw, specific airway resistance; TLC, total lung capacity.