Baseline characteristics of patients in derivation and validation cohorts
| Derivation cohort | Validation cohort | p-value | |
| Subjects | 1172 | 290 | |
| Clinical characteristics | |||
| Age years | 63 (47–74) | 66 (57–75) | 0.03 |
| Age >75 years | 265 (23) | 67 (23) | 0.93 |
| Male | 570 (49) | 117 (40) | 0.01 |
| Risk factors for VTE | |||
| Cancer# | 147 (13) | 32 (11) | 0.55 |
| Recent surgery¶ | 108 (9.2) | 23 (7.9) | 0.57 |
| Immobilisation+ | 254 (22) | 20 (6.9) | <0.001 |
| Concomitant medication | |||
| Nonsteroidal anti-inflammatory drugs | 69 (5.9) | 12 (4.1) | 0.31 |
| Antiplatelet agents | 149 (13) | 23 (7.9) | 0.02 |
| Comorbid diseases | |||
| Recent major bleeding¶ | 14 (1.2) | 13 (4.5) | <0.001 |
| COPD | 115 (9.8) | 9 (3.1) | <0.001 |
| Congestive heart failure | 58 (4.9) | 4 (1.4) | <0.01 |
| Clinical symptoms and signs at presentation | |||
| Syncope | 527 (36) | 58 (20) | <0.001 |
| Heart rate ≥110 beats·min−1 | 577 (49) | 79 (27) | <0.001 |
| Arterial oxyhaemoglobin saturation <90% | 365 (31) | 239 (82) | <0.001 |
| SBP <90 mmHg | 261 (22) | 46 (16) | 0.02 |
| Simplified PESI | |||
| Low risk | 244 (21) | 28 (10) | <0.001 |
| High risk | 928 (79) | 262 (90) | <0.001 |
| Laboratory findings | |||
| Anaemia§ | 359 (31) | 94 (32) | 0.57 |
| Platelet count <100×109·L−1 | 34 (2.9) | 25 (8.6) | <0.001 |
| Creatinine >2 mg·dL−1 | 64 (5.5) | 8 (2.8) | 0.07 |
Data are presented as n, median (interquartile range) or n (%), unless otherwise stated. VTE: venous thromboembolism; SBP: systolic blood pressure; PESI: Pulmonary Embolism Severity Index. #: active or receiving treatment in the past year; ¶: in the previous month; +: defined in this analysis as nonsurgical patients who had been immobilised (i.e. total bed rest with bathroom privileges) for ≥4 days in the month prior to pulmonary embolism diagnosis; §: <13 g·dL−1 in males, <12 g·dL−1 in females.