Mortality (%) according to baseline characteristics, with identification of subgroups with a statistically significant improved survival with continuous long-term oxygen therapy (LTOT) compared with nocturnal oxygen only (Nocturnal Oxygen Treatment Trial [30])

Variable of interestContinuous LTOT (%)Nocturnal oxygen (%)
PaCO2 ≥43mmHg (5.7kPa)19.646.0
pH <7.4016.042.2
FVC <1.89 L20.843.5
Mean room air SaO2 during sleep <85%24.450.0
Haematocrit <47.4%21.741.5
Mean PAP <27mmHg17.537.0
Pulmonary vascular resistance <279 dynes·s·cm−512.833.3

FVC: forced vital capacity; PaCO2: arterial carbon dioxide tension; PAP: pulmonary artery pressure; SaO2: arterial oxygen saturation.