AI-Driven Accurate Diagnosis of Pathogens in Severe Pneumonia

The primary outcome is the accuracy of the constructed artificial intelligence model in diagnosing the etiology of severe pneumonia. Accuracy is defined as the proportion of correct predictions made by the model out of the total number of samples. It is calculated using the formula: Accuracy = (Number of Correct Predictions) / (Total Number of Samples). The AI model will integrate multimodal data including clinical, imaging, and microbiological features. The diagnostic performance of the model will be compared against a gold standard.

The primary outcome is the identification of distinct immune subtypes in patients with severe pneumonia using an artificial intelligence model that integrates multimodal data, including clinical parameters, imaging, and immunomics. The study aims to reveal the dynamic evolution of host immune responses. The model will identify at least 3 potential immune subtypes (such as immune hyperactivation, immunosuppression, and mixed types) with significant differences in clinical outcomes like mortality .

Through the multicenter cohort, the study aims to systematically compare the differences in clinical outcomes, pathogen spectrum, and immune response characteristics between CAP and HAP patients. This comparison will help clarify the distinct clinical features and etiological backgrounds of these two types of pneumonia.

The study aims to explore the triggering conditions for hospital-acquired pneumonia (HAP), specifically identifying key predictive indicators for nosocomial and secondary infections, and to establish a predictive model for HAP. This will involve analyzing clinical, microbiological, and host immune data from the multicenter cohort to identify risk factors and early warning signs.

The study will systematically collect serological tests, microbial culture, PCR, and metagenomic sequencing data to comprehensively characterize the pathogen spectrum of severe pneumonia. By integrating this with host immune indicators (such as lymphocyte subsets, cytokines) and clinical outcomes, the study aims to investigate how different pathogens (e.g., bacteria, viruses, fungi, and mixed infections) specifically drive host immune responses. This outcome seeks to reveal the dynamic association between "pathogen-host immunity-clinical outcome", providing a basis for targeted therapy.

This outcome explores the association between the dynamic evolution trajectory of immune subtypes and patient prognosis. Cox proportional hazards models will be used to analyze the independent relationship between subtypes and prognosis.

The study aims to build an intelligent prognostic prediction model for severe pneumonia by integrating multimodal data, including clinical baseline information, scoring systems (APACHE II, SOFA), imaging features (CT/X-ray), laboratory indicators, and dynamic immune data. This is an exploratory research endpoint to determine if the AI model can predict 28-day all-cause mortality in patients with severe pneumonia.

The study aims to explore and identify specific biomarkers for different immune subtypes of severe pneumonia, particularly viral severe pneumonia (VSP), and evaluate their diagnostic efficacy. This involves using SHAP and other interpretability techniques to screen for key biomarker combinations from complex multi-omics features. The diagnostic performance of these subtype-specific biomarkers will be validated, aiming for an Area Under the Curve (AUC) greater than 0.75. This exploration is part of developing a simplified clinical diagnostic panel based on key immune markers and clinical data.