Nosocomial and Community Acquired Legionella Pneumophila Pneumonia.

Study Overview
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Brief Summary
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Legionnaire's disease (LD) is a major cause of both community acquired and nosocomial pneumonia, with Legionella pneumophila serogroup A (Lp1) being the most virulent and the greatest cause of disease. Sample culture of low respiratory tract is considered the gold standard in the diagnosis of LD, however its sensitivity seems to be poor and its performance is technically demanding. The introduction of urinary antigen detection testing (LUA) brought a major advance in LD diagnosis, with upt to 95% of cases in Europe being diagnosed with this method. Despite the high sensitivity of LUA for Lp1, ranging from 80-90%, its negative predictive value is low in other serogroup than Lp1 and therefore, Legionella may be unrecognized as agent of pneumonia. Although underdiagnosed and underreported, LD represents the second most common cause of pneumonia requiring admission in intensive care unit (ICU). Average fatality rate of LD in Europe reaches 10%, but its mortality is considered to be even higher in nosocomial patients. Despite the higher fatality rate in hospitalized LD patients, poor is the knowledge on the risk factors that could induce disease and that increase mortality in the hospitalized population affected by LD. In order to shed more light on this topic a cohort of patients diagnosed with LD in the last 3 years will be retrospectively examined.

Official Title
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Nosocomial and Community Acquired Legionella Pneumophila Pneumonia, a Retrospective Case Series

Conditions
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Legionnaires' Disease

Intervention / Treatment
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* Other: Data extraction from medical files


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All confirmed human cases of Legionnaires' disease diagnosed within the CHU Brugmann hospital within the last 3 years, from 01/01/2016 till 31/12/2018. A similar approach will be followed for the St Pierre and the UZ Brussel Hospitals. Exclusion Criteria: Pregnant women.

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 |
| --- | --- |
| Legionnaires' disease<br>All confirmed human cases of Legionnaires' disease diagnosed within the CHU Brugmann hospital within the last 3 years: from 01/01/2016 till 31/12/2018. A similar approach will be followed for the St Pierre Hospital and the UZ Brussel Hospital. | Other: Data extraction from medical files<br>* Data extraction from medical files<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| All cause mortality | All cause mortality | 3 years | 
| Severity respiratory failure | Arterial pression of oxygen inferior to 600mmHg at diagnosis | 3 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Age | Age at diagnosis | One day | 
| Sex | Sex | One day | 
| Charlson comorbidity index | This is a health tool that assesses the comorbidity risk associated to a series of conditions in order to offer medical specialists an informed decision making process in terms of specific screenings or medical procedures.The index accounts for the patient age and 16 different conditions, and ranges from 0 till 37. | One day | 
| Smoking status | Smoking (yes/no) at diagnosis | One day | 
| Nosocomial disease (yes/no) | Nosocomial cases of Legionnaires' disease are defined in this study as having an onset of symptoms more than 10 days after hospitalization. | One day | 
| C reactive protein | C reactive protein level at diagnosis | One day | 
| White blood cells | White blood cells level at diagnosis | One day | 
| Creatinine | Creatinine level at diagnosis | One day | 
| Urea | Urea level at diagnosis | One day | 
| Chest X Ray | Descriptive analysis of Chest X Ray findings at diagnosis | One day | 
| Method of diagnosis | Name of the method of diagnosis (urinary antigen, seroconversion, cultures). | One day | 
| Intensive care unit hospitalization | Intensive care unit hospitalization (yes/no) | One day | 
| Antibiotics | Name of antibiotics given | One day | 
| Antibiotic treatment duration | Antibiotic treatment duration | up to 40 days |