Nonparametric Glucose Prediction for Patient-Specific Accuracy

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Solution Overview

Problem

Existing glucose-insulin models, both white-box and black-box, struggle to accurately predict blood glucose levels due to inter- and intra-patient variability, leading to inefficiencies in model-based glucose prediction and control systems for type-1 diabetes management.

Innovation Solution

Employing a patient-specific, individualized linear black-box model using a non-parametric approach with a Stable-Spline Kernel and Kalman filter to predict future blood glucose concentrations, addressing collinearity issues through input transformation and optimizing kernel hyperparameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If parametric model-learning algorithms are used to predict blood glucose concentrations, then the model structure is simpler and easier to implement, but the prediction accuracy is insufficient due to inter- and intra-patient variability

Engineering Contradiction:
Improvemodel implementation easeVSAvoidprediction accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent transitions from parametric models with fixed structural parameters to non-parametric models where the impulse response functions are estimated without assuming a specific parametric form. This allows the model to adapt to individual patient characteristics and temporal variations, significantly improving prediction accuracy while maintaining computational tractability through kernel-based methods in RKHS.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs time-varying impulse response functions that can adapt to intra-patient variability over time. The non-parametric approach allows the model dynamics to change according to individual patient responses rather than being constrained by fixed parametric structures, enabling the system to capture evolving physiological patterns.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If individualized patient-specific models are created to address inter- and intra-patient variability, then the prediction accuracy improves, but the model complexity and computational requirements increase

Engineering Contradiction:
Improveprediction accuracyVSAvoidmodel complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex parametric model identification procedures with non-parametric methods based on Gaussian regression and kernel functions in RKHS. This substitution simplifies the mathematical framework by avoiding the need to specify and estimate multiple parametric parameters, while still achieving individualized patient-specific modeling through data-driven impulse response estimation.

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

Solution Approach 2:

The patent develops a universal non-parametric framework that can be applied to all patients without requiring patient-specific parameter tuning. The kernel-based approach in RKHS provides a unified methodology that automatically adapts to individual patient characteristics through the data, eliminating the need for separate model development procedures for each patient.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If non-parametric approach with RKHS is used to estimate impulse response functions, then the prediction accuracy significantly improves, but the computational complexity increases

Engineering Contradiction:
Improveprediction accuracyVSAvoidcomputational power
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent transforms the infinite-dimensional non-parametric estimation problem in RKHS into a finite-dimensional optimization problem by exploiting the reproducing kernel property. This allows the impulse response functions to be expressed as linear combinations of kernel functions evaluated at training data points, reducing computational complexity while maintaining the flexibility of non-parametric modeling.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4268242B1Nonparametric glucose predictors
Publication Date: 2025.12.17 DEXCOM INC
  • EP4268242B1 patent drawingFigure 1~2B
  • EP4268242B1 patent drawingFigure 3~4
  • EP4268242B1 patent drawingFigure 5A~5B

AI summary

A method of predicting future blood glucose concentrations of an individual patient includes: identifying an individualized linear black box model of glucose-insulin by estimating a plurality of impulse response functions each accounting for an input-output relation of a plurality of individualized patient data sets, the impulse response functions being functions in a Reproducing Kernel Hilbert Space (RKHS); and applying a linear predicting technique to the selected model using the identified impulse response functions to obtain a predicted blood glucose concentration of the individual patient at a future time.