Clinical characteristics of the patients studied
| Non-survivors | Survivors | p Value | |
|---|---|---|---|
| Age (years) | 72±10 | 69±5 | 0.22 |
| Male/female | 23/9 | 14/5 | 0.91 |
| Smoking history (±) | 23/9 | 15/4 | 0.48 |
| Smoking index (pack-years) | 28±25 | 45±37 | 0.071 |
| Duration of symptoms before admission (days) | 7±4 | 14±9 | 0.0069 |
Comparison between groups was performed by Mann-Whitney's U test (for continuous variables) or the χ2 test (for categorical variables).