Primary and Secondary Pneumothoraces Compared
The table below provides a comparison between primary and secondary pneumothoraces.
| Primary | Secondary | |
| Peak incidence age (years) | 20-30 | 60-70 |
| Male:frmale ratio | 6:1 | 3:1 |
| Aetiology | Ruptured sub-pleural bleb | Various |
| Proportion of all spontaneous pneumothoraces | 80-90% | 10-20% |
| 1 year recurrence rate (without pleurodesis) | 25% | Higher but dependent on underlying condition |