Risk Stratification in Patients with Complicated Parapneumonic Effusions and Empyema Using the RAPID Score

Complicated parapneumonic effusions and empyema are a leading cause of morbidity in the United States with over 1 million admissions annually and a mortality rate that remains high in spite of recent advances in diagnosis and treatment. The identification of high risk patients is crucial for improved management and the provision of cost-effective care. The RAPID score is a scoring system comprised of the following variables: renal function, age, purulence, infection source, and dietary factors and has been shown to predict outcomes in patients with pleural space infections.

In a single center retrospective study, we evaluated 98 patients with complicated parapneumonic effusions and empyema who had tube thoracostomy (with or without Intrapleural fibrinolytic therapy) and assessed treatment success rates, mortality, length of hospital stay, and direct hospitalization costs stratified by three RAPID score categories: low-risk (0-2), medium risk (3-4), and high-risk (5-7) groups.

Treatment success rate was 71%, and the 90 day mortality rate was 12%. There was a positive-graded association between the low, medium and high RAPID score categories and mortality, (5.3%, 8.3% and 22.6%, respectively), length of hospital stay (10, 21, 19 days, respectively), and direct hospitalization costs ($19,909, $36,317 and $43,384, respectively).

Our findings suggest that the RAPID score is a robust tool which could be used to identify patients with complicated parapneumonic effusions and empyema who may be at an increased risk of mortality, prolonged hospitalization, and who may incur a higher cost of treatment. Randomized controlled trials identifying the most effective initial treatment modality for medium- and high-risk patients are needed.