Proportions of causes of non-malignant pleural effusions
| Condition | Patients |
| Pleural infection# | 131 (40.0%) |
| Congestive cardiac failure | 81 (34.8%) |
| Idiopathic pleuritis/undiagnosed | 41 (12.5%) |
| Benign asbestos pleural effusion | 27 (8.3%) |
| Liver cirrhosis | 13 (4.0%) |
| Renal failure | 10 (3.1%) |
| Pulmonary embolism | 6 (1.8%) |
| Post-coronary artery bypass graft | 4 (1.2%) |
| Drug reaction | 3 (0.9%) |
| Rheumatoid effusion | 3 (0.9%) |
| Trapped lung | 2 (0.6%) |
| Pancreatitis | 2 (0.6%) |
| Other¶ | 4 (1.2%) |
#: e.g. parapneumonic effusions, empyema or tuberculous pleural effusions; ¶: e.g. peritoneal dialysis, systemic lupus erythematosus or a result of paint inhalation.