GBM-LIME Mortality Prediction System for Clinical Interpretability

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Solution Overview

Problem

Traditional risk prediction models in surgery, such as high-risk cardiac surgery, fail to adequately explain the complex interplay of clinical variables and their changing significance, leading to uncertainty in outcome prediction.

Innovation Solution

The use of a system and method that combines gradient boosting machine (GBM) modeling with local interpretable model-agnostic explanations (LIME) to provide patient-specific post-surgery mortality predictions, identifying the most contributing pre-operative factors and their relative impact on mortality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional statistical approaches are used for risk prediction modeling, then the model is simple and interpretable, but the model cannot adequately capture the complex interplay of clinical variables and their changing significance

Engineering Contradiction:
Improveability to capture complex variable interactionsVSAvoidmodel complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system segments the complex prediction task into two distinct components: a gradient boosting machine (GBM) model that captures complex non-linear relationships and variable interactions, and a separate interpretable model (such as LIME or SHAP) that explains the predictions. This segmentation allows each component to specialize - the GBM handles complexity while the interpretable model handles explanation, resolving the contradiction between capturing complex interactions and maintaining interpretability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary layer between the complex GBM model and the final interpretation. This intermediary consists of explanation techniques (LIME/SHAP) that act as mediators, translating the complex internal representations of the GBM into human-understandable explanations. This intermediary allows the system to maintain the predictive power of complex models while providing the interpretability needed for clinical decision-making.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If machine learning models are used to accurately predict mortality, then prediction accuracy is improved, but the model becomes less interpretable and harder to explain to clinicians

Engineering Contradiction:
Improvemortality prediction accuracyVSAvoidinterpretability information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The system separates the prediction function from the explanation function. The GBM model segment handles prediction accuracy by learning complex patterns from data, while the interpretable model segment handles explanation by providing human-understandable insights. This segmentation allows the system to achieve high prediction accuracy without sacrificing interpretability, as each segment specializes in its respective function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local interpretability techniques (LIME/SHAP) that provide explanations specific to individual patient cases rather than global model explanations. This local quality approach allows the system to maintain high overall prediction accuracy while providing tailored, interpretable explanations for each specific prediction, addressing the needs of clinicians for case-by-case understanding.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If traditional linear models are used, then the model is easy to implement and interpret, but the model fails to capture the non-linear relationships and changing significance of clinical variables

Engineering Contradiction:
Improveease of implementationVSAvoidprediction reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The system segments the modeling task into a complex GBM component that captures non-linear relationships and an interpretable component that maintains ease of understanding. The GBM handles the complex pattern recognition while the interpretable model provides straightforward explanations, allowing the system to achieve high reliability through accurate non-linear modeling while maintaining ease of implementation through simple explanation interfaces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces traditional mechanical statistical modeling approaches with machine learning-based GBM models that automatically learn complex relationships from data. This substitution eliminates the need for manual specification of linear relationships and interactions, allowing the model to automatically capture non-linear patterns while the system remains implementable through automated processing pipelines.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20230290515A1Machine learning based patient specific post-surgery mortality prediction system and related methods
Publication Date: 2023.09.14 UNIV OF SOUTH FLORIDA
  • US20230290515A1 patent drawing
  • US20230290515A1 patent drawing
  • US20230290515A1 patent drawing

AI summary

Methods and systems for patient-specific post-surgery mortality prediction are disclosed. The methods and systems include: receiving a plurality of pre-operative factor indications for a patient; obtaining a first trained machine learning model and an interpretable model; applying the plurality of pre-operative factor indications to the first trained machine learning model to obtain a plurality of confidence values corresponding to the plurality of pre-operative factor indications; applying the plurality of confidence values to the interpretable model to obtain a plurality of interpretation indications, the plurality of interpretation indications corresponding to a subset of the plurality of pre-operative factor indications, the plurality of interpretation indications most contributing to mortality of the patient, the plurality of interpretation indications being specific to the patient; and outputting a survival probability of the patient based on the plurality of interpretation indications. Other aspects, embodiments, and features are also claimed and described.