| Factor | Odds Ratio (95% CI) | P-value |
| Charlson comorbidity index | 1.95 (1.08, 3.52) | 0.03 |
| APACHE II score(*) | 4.80 (1.48, 15.6) | 0.009 |
| Anaemia at admission No | 1 |
|
| Yes | 12.5 (1.48, 106) | 0.02 |