Population description and comparison between survivors and those who died inhospital
| Variable | Total population, n=920 | Survived to discharge, n=824 | Died in hospital, n=96 | p Value* |
| Socio-demographic details | ||||
| Age (years) | 73.1 (10.0) | 72.3 (10.0) | 79.2 (8.0) | <0.001 |
| Female, % | 53.9 | 54.2 | 51.0 | 0.59 |
| Smoking burden (cigarette pack years), median (IQR) | 45 (32–60) | 45 (32–60) | 42.5 (30–60) | 0.69 |
| Institutional care, % | 6.5 | 5.2 | 17.7 | <0.001 |
| Living independently, % | 77.1 | 79.9 | 53.1 | <0.001 |
| Housebound, % | 34.2 | 28.9 | 80.2 | <0.001 |
| Markers of disease severity | ||||
| Number of hospital admissions in previous year, median (IQR) | 0 (0–1) | 0 (0–1) | 1 (0–2) | 0.096 |
| Number of AECOPD in previous year, median (IQR) | 3 (1–4) | 3 (1–4) | 3 (2–4) | 0.57 |
| FEV1 (% predicted)‡ | 43.6 (17.2) | 44.0 (17.4) | 39.9 (14.2) | 0.010 |
| FVC (litre)‡ | 2.15 (0.8) | 2.18 (0.8) | 1.86 (0.6) | <0.001 |
| eMRCD, median (IQR) | 4 (4–5a) | 4 (3–5a) | 5a (5a–5b) | <0.001 |
| Long-term oxygen therapy, % | 12.4 | 11.3 | 21.9 | 0.004 |
| Previous admission requiring NIV, % | 10.9 | 10.4 | 14.6 | 0.23 |
| Cor pulmonale, % | 10.0 | 9.8 | 11.5 | 0.72 |
| Long-term prednisolone, % | 9.1 | 8.7 | 12.5 | 0.23 |
| Home nebulised therapy, % | 16.6 | 16.6 | 16.7 | 0.99 |
| Comorbidity | ||||
| Cerebrovascular disease, % | 14.0 | 12.6 | 26.0 | 0.001 |
| Ischaemic heart disease, % | 29.3 | 29.5 | 28.1 | 0.81 |
| Hypertension, % | 39.6 | 39.2 | 42.7 | 0.51 |
| Diabetes, % | 14.8 | 14.7 | 15.6 | 0.88 |
| Atrial fibrillation, % | 12.5 | 10.9 | 26.0 | <0.001 |
| Left ventricular dysfunction, % | 7.3 | 7.4 | 6.3 | 0.84 |
| Chronic kidney disease, % | 6.7 | 5.7 | 15.6 | 0.001 |
| Cognitive impairment, % | 5.4 | 4.6 | 12.5 | 0.003 |
| Admission clinical data† | ||||
| Purulent sputum, % | 51.3 | 52.6 | 39.6 | 0.020 |
| Ineffective cough, % | 11.8 | 9.3 | 33.3 | <0.001 |
| Pedal oedema, % | 27.7 | 26.9 | 34.5 | 0.16 |
| Acute confusion, % | 12.6 | 10.0 | 35.4 | <0.001 |
| Heart rate/min | 102.7 (20.8) | 102.7 (20.5) | 102.7 (23.3) | 0.98 |
| Systolic blood pressure (mm Hg) | 139.3 (28.4) | 139.7 (28.1) | 135.4 (30.6) | 0.16 |
| Diastolic blood pressure (mm Hg) | 76.2 (17.0) | 76.6 (16.7) | 72.8 (19.1) | 0.038 |
| Respiratory rate/min | 26.0 (6.3) | 25.8 (6.1) | 27.8 (7.6) | 0.004 |
| Temperature (°C), median (IQR) | 36.9 (36.4–37.5) | 36.9 (36.4–37.6) | 36.8 (36.2–37.3) | 0.095 |
| Oxygen saturation (%), median (IQR) | 92 (87–96) | 92 (87–96) | 92 (86–96) | 0.99 |
| BMI (kg/m2) | 24.6 (6.3) | 24.8 (6.3) | 22.5 (6.1) | 0.001 |
| Weight loss >5%, % | 24.6 | 22.5 | 42.7 | <0.001 |
| Radiographic consolidation, % | 32.5 | 29.0 | 62.5 | <0.001 |
| Arterial blood gas values† | ||||
| pH, median (IQR) | 7.41 (7.36–7.45) | 7.42 (7.37–7.45) | 7.38 (7.28–7.45) | 0.001 |
| paO2 (kPa), median (IQR) | 8.7 (7.3–10.7) | 8.7 (7.3–10.5) | 8.4 (7.1–12.7) | 0.82 |
| paCO2 (kPa), median (IQR) | 5.9 (4.9–7.5) | 5.8 (4.9–7.3) | 6.4 (5.2–9.2) | 0.004 |
| Bicarbonate (mmol/l) | 29.1 (6.5) | 29.0 (6.3) | 30.0 (8.0) | 0.22 |
| Acidotic exacerbation, %§ | 19.3 | 18.1 | 30.2 | 0.006 |
| Laboratory investigations† | ||||
| Sodium (mmol/l) | 136.3 (4.6) | 136.3 (4.5) | 136.7 (5.0) | 0.39 |
| Potassium (mmol/l) | 4.32 (0.6) | 4.3 (0.5) | 4.5 (0.7) | 0.002 |
| Urea (mmol/l), median (IQR) | 6.5 (4.7–9.3) | 6.3 (4.6–8.8) | 9.5 (6.0–14.2) | <0.001 |
| Creatine (μmol/l), median (IQR) | 93 (77–114) | 92 (77–112) | 100 (75–148) | 0.049 |
| Chloride (mmol/l) | 98.6 (8.8) | 98.7 (9.1) | 97.9 (6.1) | 0.41 |
| Albumin (g/l) | 38.4 (4.8) | 38.7 (4.6) | 35.4 (5.3) | <0.001 |
| Glucose (mmol/l), median (IQR) | 6.9 (6.0–8.1) | 6.9 (6.0–8.0) | 7.4 (6.0–8.9) | 0.030 |
| Haemoglobin (g/dl) | 13.6 (1.9) | 13.6 (1.9) | 13.0 (2.2) | 0.004 |
| White cell count (×109/l), median (IQR) | 12.0 (9.1–15.5) | 11.8 (9.1–15.3) | 12.7 (9.5–17.1) | 0.070 |
| Neutrophil count (×109/l), median (IQR) | 9.2 (6.9–12.8) | 9.1 (6.8–12.6) | 10.5 (7.7–15.2) | 0.007 |
| Eosinophil count (×109/l), median (IQR) | 0.1 (0–0.2) | 0.1 (0–0.2) | 0 (0–0.1) | <0.001 |
| CRP (mg/l), median (IQR) | 42 (11–117) | 36 (10–111) | 89 (30–145) | <0.001 |
All figures quote mean (SD) unless otherwise stated.
↵* Comparison of survivors and those who died in hospital.
↵† At the time of hospital admission.
↵‡ Performed within 2 years of admission; self-reported unintentional weight loss during the preceding 6 months.
↵§ pH <7.35 and paCO2 >6 kPa.
AECOPD, acute exacerbations of chronic obstructive pulmonary disease; BMI, body mass index; CRP, C reactive protein; eMRCD, extended MRC dyspnoea; FEV1, forced expiratory volume in one second; FVC, forced vital capacity; NIV, non-invasive ventilation.