| Characteristic | No (%) patients* |
| Demographics | |
| Mean (SD) age (years) | 65.7 (20.1) |
| Age >50 years | 967 (77.9) |
| Age ⩾65 years | 759 (61.1) |
| Female sex | 481 (38.7) |
| Nursing home resident | 153 (12.3) |
| Comorbid illnesses | |
| Heart failure | 201 (16.2) |
| Cerebrovascular disease | 341 (27.5) |
| Neoplastic disease | 81 (6.5) |
| Renal disease | 131 (10.5) |
| Liver disease | 20 (1.6) |
| Physical examination findings | |
| Altered mental status | 221 (17.8) |
| Pulse ⩾125/min | 174 (14.0) |
| Respiratory rate ⩾30/min | 80 (6.4) |
| Systolic blood pressure <90 mm Hg | 84 (6.8) |
| Diastolic blood pressure ⩽60 mm Hg | 373 (30.0) |
| Temperature <35°C or ⩾40°C | 33 (2.7) |
| Laboratory and radiological findings | |
| BUN ⩾11 mmol/l | 260 (20.9) |
| BUN >7 mmol/l | 482 (38.8) |
| Glucose ⩾14 mmol/l | 112 (9.0) |
| Haematocrit <30% | 150 (12.1) |
| Sodium <130 mmol/l | 181 (14.6) |
| Pao2 <60 mm Hg or Sao2 <90% | 285 (22.9) |
| Arterial pH <7.35 | 92 (7.4) |
| Pleural effusion | 265 (21.3) |
*Data were complete for all patients except the following variables: BUN (0.7% missing), glucose (10.5% missing), sodium (0.6% missing), Pao2 or Sao2 (2.4% missing), arterial pH (73.6% missing).
BUN, blood urea nitrogen; Pao2, arterial oxygen tension; Sao2, oxygen saturation.