Background Infection of the pleural cavity invariably leads to hospitalisation, and a fatal outcome is not uncommon. Our aim was to study the epidemiology of pleural empyema on a nationwide basis in the whole population and in three subgroups of patients, namely post-lung resection, associated cancer and those with no surgery and no cancer.

Methods Data from patients aged ≥18 years hospitalised with a diagnosis of pleural infection in France between January 2013 and December 2017 were retrieved from the medical-administrative national hospitalisation database and retrospectively analysed. Mortality, length of stay and costs were assessed.

Results There were 25 512 hospitalisations for pleural empyema. The annual rate was 7.15 cases per 100 000 habitants in 2013 and increased to 7.75 cases per 100 000 inhabitants in 2017. The mean age of patients was 62.4±15.6 years and 71.7% were men. Post-lung resection, associated cancer and no surgery–no cancer cases accounted for 9.8%, 30.1% and 60.1% of patients, respectively. These groups were significantly different in terms of clinical characteristics, mortality and risk factors for length of stay, costs and mortality. Mortality was 17.1% in the whole population, 29.5% in the associated cancer group, 17.7% in the post-lung resection group and 10.7% in the no surgery–no cancer group. In the whole population, age, presence of fistula, higher Charlson Comorbidity Index (>3), alcohol abuse, arterial hypertension, hyperlipidaemia, atheroma, atrial fibrillation, performance status >3 and three subgroups of pleural empyema independently predicted mortality.

Conclusions Empyema is increasing in incidence. Factors associated with mortality are recent lung resection and associated diagnosis of cancer.