Comparison of the patients admitted and not admitted to the intensive care unit according to the admission characteristics
| Characteristics | Admitted | Not admitted | p-value |
| Subjects n | 45 | 160 | |
| Age yrs | 63.7±11.0 | 65.2±8.6 | ns |
| Sex female/male | 2/15 | 23/165 | ns |
| Duration of disease yrs | 11.6±9.0 | 9.9±8.2 | ns |
| Time elapsed since first hospitalisation yrs | 5.6±6.1 | 5.2±6.3 | ns |
| Smoking status yes/ex/never | 18/22/5 | 77/61/22 | ns |
| Smoke load pack-yrs | 50.4±27.7 | 48±31.7 | ns |
| Duration hospital stay days | 11.5±6.9 | 11.6±4.9 | ns |
| Albumin g·dL−1 | 3.3±0.6 | 3.4±0.8 | ns |
| FVC % predicted | 57.0±18.8 | 64.5±21.6 | 0.047 |
| FEV1 % predicted | 35.3±11.3 | 39.1±13.6 | ns |
| FEV1/FVC | 51.3±19.7 | 49.8±15.4 | ns |
| Pa,O2 mmHg | 42.0±9.2 | 49.5±13.4 | 0.001 |
| Pa,CO2 mmHg | 52.1±9.8 | 47.9±13.1 | 0.025 |
| Sa,O2 | 74.6±10.7 | 82.0±11.2 | 0.000 |
| pH | 7.40±0.08 | 7.41±0.07 | ns |
| BMI kg·m−2 | 21.5±3.5 | 23.5±5.0 | ns |
| Ppa mmHg | 48.1±8.0 | 49.2±8.1 | ns |
| Long-term oxygen treatment | 15 | 42 | ns |
| Comorbidity index | 1.61±0.9 | 1.58±0.8 | ns |
| Patients with medical insurance % | 96 | 96 | ns |
| Married or living with relatives % | 91 | 94 | ns |
Data presented as mean±sd, n or %, unless otherwise stated. FVC: forced vital capacity; FEV1: forced expiratory volume in one second; Pa,O2: arterial oxygen tension; Pa,CO2: carbon dioxide arterial tension; Sa,O2: arterial oxygen saturation; BMI: body mass index; Ppa: systolic pulmonary artery pressure; ns: not significant. kPa = mmHg×0.133.