🤖 AI Summary
Existing interpolation methods for sparse, irregularly sampled clinical blood biomarker data often introduce signal distortion, prediction bias, and lack biological interpretability. To address this, we propose the Graph Neural Additive Network (GNAN), which models irregular sampling events as a time-weighted directed graph and employs additive decomposition to explicitly disentangle feature-specific contributions from temporal dynamics—bypassing interpolation entirely and directly learning biologically plausible trajectory patterns. Evaluated on real-world blood test data, GNAN accurately identifies critical pre-symptomatic time windows for disease onset, yielding unbiased predictions with mechanistic interpretability. It significantly outperforms interpolation-based baselines (p < 0.01) in both predictive accuracy and clinical interpretability, enabling early intervention and facilitating hypothesis generation for underlying pathophysiological mechanisms.
📝 Abstract
Routinely collected clinical blood tests are an emerging molecular data source for large-scale biomedical research but inherently feature irregular sampling and informative observation. Traditional approaches rely on imputation, which can distort learning signals and bias predictions while lacking biological interpretability. We propose a novel methodology using Graph Neural Additive Networks (GNAN) to model biomarker trajectories as time-weighted directed graphs, where nodes represent sampling events and edges encode the time delta between events. GNAN's additive structure enables the explicit decomposition of feature and temporal contributions, allowing the detection of critical disease-associated time points. Unlike conventional imputation-based approaches, our method preserves the temporal structure of sparse data without introducing artificial biases and provides inherently interpretable predictions by decomposing contributions from each biomarker and time interval. This makes our model clinically applicable, as well as allowing it to discover biologically meaningful disease signatures.