Retrospective Review on Patients With Culture Negative Empyema

Study Overview
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Brief Summary
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Empyema is associated with a wide range of complication and mortality. It is defined by either a positive pleural fluid culture or grossly pus appearance. However, little is known about the differences in aetiology and outcome between culture-positive empyema (CPE) and culture-negative empyema (CNE). The aim of the current study is to look at the local prevalence of CNE, and compare the clinical outcome between CPE and CNE.

Detailed Description
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Pneumonia is a common disease and it ranked second as the leading cause of death in Hong Kong in 2016. Among patients suffering from acute pneumonia, up to 57% of them would develop parapneumonic effusion. Without proper treatment, parapneumonic effusion would progress into empyema, which is a clinical emergency. Empyema leads to a longer length of hospital stay, a higher rate of complication and mortality than uncomplicated parapneumonic effusion. The mainstay of treatment for empyema is antibiotics and drainage. Therefore, identification of causative microorganism is important in guiding the choice of antibiotics. The common bacterial culprits, for community acquired and hospital acquired, were identified by various local and international studies. However, the aetiological agents were still unknown in up to 40% of cases. In addition, the clinical outcomes between culture negative empyema (CNE) and culture positive empyema (CPE) are largely unknown. Data from one Taiwanese study suggested that patients with CPE had a higher in-hospital mortality than those with CNE. However, the primary objective of this study was not putting on the importance of CNE. Therefore, data on outcome of CNE patients remain largely uncertain, either worldwide and local population. The aim of the current study is to look at the local prevalence of CNE, and compare the clinical outcome between CPE and CNE. Through more understanding of CNE, the clinical management of this patient group may be altered and a better patient outcome is anticipated.

Official Title
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Retrospective Review on Patients With Culture Negative Empyema

Conditions
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Empyema, Pleural

Intervention / Treatment
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* Other: Disease outcome (mortality)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: i. All patients hospitalized for empyema, defined by the presence of purulent pleural fluid or positive culture result from pleural fluid ii. Age greater than 18 years old Exclusion Criteria: i. Inappropriate diagnosis of empyema after evaluation ii. Tuberculous pleuritis, defined by presence of Mycobacterium tuberculosis culture from pleural fluid or granulomatous inflammation on pleural biopsy histology

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Culture positive empyema<br>Patients with empyema confirmed by a positive pleural fluid culture, irrespective of its gross fluid appearance | Other: Disease outcome (mortality)<br>* Mortality rate between the two groups<br>|
| Culture negative empyema<br>Patients with empyema confirmed by a gross pus appearance AND a negative pleural fluid culture | Other: Disease outcome (mortality)<br>* Mortality rate between the two groups<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Compare the mortality rate within same admission between patients with culture-positive empyema (CPE) and culture-negative empyema (CNE) | Compare the mortality rate within same admission between patients with culture-positive empyema (CPE) and culture-negative empyema (CNE) | Within the same episode of hospitalization or 7 days, whichever longer | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prevalence of negative pleural fluid culture in patients with empyema | Prevalence of negative pleural fluid culture in patients with empyema | 6 years | 
| b. Compare other clinical outcomes (length of hospital stay, duration of intravenous antibiotics, number of pleural drainage received, need of surgical treatment, 30-days and 90-days mortality) between patients with CNE and CPE | Compare other clinical outcomes (length of hospital stay, duration of intravenous antibiotics, number of pleural drainage received, need of surgical treatment, 30-days and 90-days mortality) between patients with CNE and CPE | Within the same episode of hospitalization or 90 days, whichever longer | 
| Investigate the risk factors of failure to obtain culture results in patients with CNE | Investigate the risk factors of failure to obtain culture results in patients with CNE | Within the same episode of hospitalization or 7 days, whichever longer | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Culture positive empyema, Culture negative empyema, Parapneumonic effusion, Pleural fluid, Pneumonia