Accuracy of Lung Injury Biomarkers in the Initial Investigation of Patients With Suspected Pneumonia

Study Overview
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Brief Summary
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The aim of this study is to investigate the diagnostic and prognostic value of surfactant protein D, Krebs von den Lungen (KL-6), and Chitinase-3-like protein 1 (YKL-40) in the initial investigation of patients hospitalized with suspected pneumonia. This to improve the diagnosis of pneumonia, contribute to a more rapid and accurate antibiotic treatment, and assess disease severity to predict short-term and long-term mortality in community-acquired pneumonia patients.

Detailed Description
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Community-acquired pneumonia (CAP) is one of the most common infection diseases in the emergency department (ED). Diagnosis of pneumonia is challenging as symptoms are often weak and nonspecific and the current methods for focal and etiological diagnosis have low sensitivity and specificity and often deliver results after the antibiotic treatment decision has been made. The abundant and restricted expression of surfactant protein D (SP-D) within the lung makes this protein a specific marker for lung disease. Krebs von den Lungen-6 (KL-6) is expressed in the lung and is a diagnostic and prognostic marker of interstitial lung disease. The inflammatory glycoprotein Chitinase-3-like protein 1 commonly known as YKL-40 is associated with severity of interstitial lung disease. The value of these lung injury markers for diagnosing pneumonia needs further investigation. The investigators hypothesize that surfactant protein D, Krebs von den Lungen (KL-6), and Chitinase-3-like protein 1 (YKL-40) have an impact on diagnosing, prognosis, and treatment of patients with verified CAP. The objectives of the study are: To investigate the diagnostic accuracy of surfactant protein D, Krebs von den Lungen (KL-6), and Chitinase-3-like protein 1 (YKL-40) in the diagnosis of CAP To identify the prognostic value surfactant protein D, Krebs von den Lungen (KL-6), and Chitinase-3-like protein 1 (YKL-40) in relation to adverse events in patients with verified CAP

Official Title
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Diagnostic and Prognostic Accuracy of Surfactant Protein D, Krebs Von Den Lungen, and Chitinase-3-like Protein 1 (YKL-40 ) in the Initial Investigation of Patients With Suspected Pneumonia

Conditions
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Community-acquired Pneumonia

Intervention / Treatment
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* Diagnostic Test: Biomarkers for pneumonia


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Suspicion of APN assessed by the receiving physician at the ED Exclusion Criteria: If the attending physician considers that participation will delay a life-saving treatment or patient needs direct transfer to the intensive care unit. Admission within the last 14 days Verified COVID-19 disease within 14 days before admission Pregnant women Severe immunodeficiencies: Primary immunodeficiencies and secondary immunodeficiencies (HIV positive CD4 <200, Patients receiving immunosuppressive treatment (ATC L04A), Corticosteroid treatment (>20 mg/day prednisone or equivalent for >14 days within the last 30 days), Chemotherapy within 30 days)

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 |
| --- | --- |
| Suspected CAP<br>All patients admitted to the emergency department with suspected community-acquired pneumonia (CAP) assessed by the receiving physician | Diagnostic Test: Biomarkers for pneumonia<br>* Blood samples will be collected by a medical laboratory technologist and transferred to the local laboratory for analysis of surfactant protein D, Krebs von den Lungen (KL-6), and YKL-40. Laboratory staff will be blinded to participant diagnosis and outcome. None of the biomarkers will be available to the treating physician. Diagnostic test of surfactant protein D - will be quantified using enzyme-linked immunosorbent assay (ELISA)-based analysis Diagnostic test of KL-6: will be quantified using enzyme-linked immunosorbent assay (ELISA)-based analysis Diagnostic test of YKL-40 - will be quantified using enzyme-linked immunosorbent assay (ELISA)-based analysis<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Verified and non-verified community acquired pneumonia (CAP) | The decision of whether patients admitted with suspicion of CAP actually has a final diagnosis of CAP is based on a combination of all findings during admission. The verification of diagnosis requires human handling, interpretation and judgment. Therefore, in this study, an expert panel will define the reference standard for the diagnosis CAP. The expert panel consists of two independent consultants from the emergency department with significant experience in emergency medicine and acute infections. They will individually determine whether or not the patient admitted suspected with CAP actually had this diagnosis. The final diagnosis will be based on all available relevant information from the patient medical record including HR-CT of lungs. A standardized template will be used. Disagreement will be discussed until a consensus is reached. | 2 months after patient discharge | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Intensive care unit treatment | transfer to ICU during current admission (binary outcome) | within 60 days from admission to the emergency department | 
| Length of stay | days spent in hospital during current admission | within 60 days from current admission to the emergency department | 
| the number of participants who died within 30 days | binary - 30-days mortality | within 30 days from arrival day | 
| The number of participants who died within 90 days | binary - 90-days mortality | within 90 days from arrival day | 
| Readmission | binary | within 30 days from day of discharge | 
| In-hospital mortality | binary | within 60 days from admission to the emergency department | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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surfactant protein D, Krebs von den Lungen, YKL-40 C, pneumonia, lung injury, diagnostic markers, prognostic markers, emergency department