Baseline characteristics of patients included in the study
| Sex males/females | 588 (70)/254 (30) |
| Age yrs | 68.4±12.2 |
| BMI kg·m−2 | 26.9±5.6 |
| Diagnosis | |
| ILD | 77 (9.1) |
| COPD | 628 (74.2) |
| Vascular disease | 43 (5.1) |
| Others | 98 (11.6) |
| pH | 7.41±0.04 |
| Pa,O2mmHg | 58.4±10.0 |
| Pa,CO2 mmHg | 45.3±8.0 |
| Bicarbonate mmol·L−1 | 28.5±3.7 |
| Sa,O2 % | 88.6±5.7 |
| Sp,O2 % | 89.1±5.3 |
Data are presented as n (%) or mean±sd. BMI: body mass index; ILD: interstitial lung disease; COPD: chronic obstructive pulmonary disease; Pa,O2: arterial oxygen tension; Pa,CO2: arterial carbon dioxide tension; Sa,O2: arterial oxygen saturation; Sp,O2: arterial oxygen saturation measured by pulse oximetry.