| Hazard ratio (95% CI) | p Value | |
| El Escorial diagnostic category | ||
| Suspect (ref) | 1 (1) | |
| Possible | 0.4 (0.2–0.9) | 0.03 |
| Probable | 0.7 (0.3–1.5) | 0.42 |
| Definite | 0.99 (0.4–1.9) | 0.99 |
| Age at diagnosis (y) | ||
| ⩽45 (ref) | 1 (1) | |
| 45–65 | 4.7 (1.4–15.4) | 0.01 |
| 65–75 | 3.5 (1.04–11.7) | 0.04 |
| >75 | 7.5 (1.9–29.6) | 0.004 |
| Spinal onset of disease (ref) | 1 (1) | |
| Generalised or bulbar onset | 1.8 (1.1–3.0) | 0.01 |
Non-significant covariates were gender, riluzole use, percutaneous endoscopic gastrostomy and non-invasive ventilation insertion, time from onset to diagnosis and predominance of upper motoneuron signs.