Table 1

Characteristics of the idiopathic pulmonary fibrosis (IPF) patient population and the control group

IPF groupControl group
Demographic characteristics
Number of cases4141
Sex male/female15/2615/26
Age yrs63.5 (38–80)64.0 (45–83)
Smoking yes/no/missing4/35/6
Medical characteristics
Oxygen use yes/no/missing14/27
If yes now often? 24 h a day/sometimes6/8
Steroid use at time of study yes/no28/13
Time since diagnosis yrs5.8±5.4
FEV1 % pred70.1±21.5
TL, CO % pred45.3±14.9
PO2 at rest kPa9.1±1.7
PO2 during exercise kPa7.0±1.2
PO2 difference score kPa2.7±1.5
Cough yes/no35/6
Reduced exercise capacity yes/no34/7
Severity of dyspnoea possible range 0–73.8±2.0
Psychological characteristics
  • Data are expressed in means, (range) or as mean±SD

  • FEV1 forced expiration volume in one second

  • TL,CO transfer factor of the lung for carbon monoxide

  • PO2: arterial oxygen tension

  • BDI: Beck Depression Inventory

  • CDI: Cognitive Depression Index